05-20-2023-0226 - blowout (crude oil)

From Wikipedia, the free encyclopedia

The Lucas Gusher at Spindletop, Texas (1901)

A blowout is the uncontrolled release of crude oil and/or natural gas from an oil well or gas well after pressure control systems have failed.^[1] Modern wells have blowout preventers intended to prevent such an occurrence. An accidental spark during a blowout can lead to a catastrophic oil or gas fire.

Prior to the advent of pressure control equipment in the 1920s, the uncontrolled release of oil and gas from a well while drilling was common and was known as an oil gusher, gusher or wild well.

History

Gushers were an icon of oil exploration during the late 19th and early 20th centuries. During that era, the simple drilling techniques, such as cable-tool drilling, and the lack of blowout preventers meant that drillers could not control high-pressure reservoirs. When these high-pressure zones were breached, the oil or natural gas would travel up the well at a high rate, forcing out the drill string and creating a gusher. A well which began as a gusher was said to have "blown in": for instance, the Lakeview Gusher blew in in 1910. These uncapped wells could produce large amounts of oil, often shooting 200 feet (61 m) or higher into the air.^[2] A blowout primarily composed of natural gas was known as a gas gusher.

Despite being symbols of new-found wealth, gushers were dangerous and wasteful. They killed workmen involved in drilling, destroyed equipment, and coated the landscape with thousands of barrels of oil; additionally, the explosive concussion released by the well when it pierces an oil/gas reservoir has been responsible for a number of oilmen losing their hearing entirely; standing too near to the drilling rig at the moment it drills into the oil reservoir is extremely hazardous. The impact on wildlife is very hard to quantify, but can only be estimated to be mild in the most optimistic models—realistically, the ecological impact is estimated by scientists across the ideological spectrum to be severe, profound, and lasting.^[3]

To complicate matters further, the free flowing oil was—and is—in danger of igniting.^[4] One dramatic account of a blowout and fire reads,

With a roar like a hundred express trains racing across the countryside, the well blew out, spewing oil in all directions. The derrick simply evaporated. Casings wilted like lettuce out of water, as heavy machinery writhed and twisted into grotesque shapes in the blazing inferno.^[5]

The development of rotary drilling techniques where the density of the drilling fluid is sufficient to overcome the downhole pressure of a newly penetrated zone meant that gushers became avoidable. If however the fluid density was not adequate or fluids were lost to the formation, then there was still a significant risk of a well blowout.

In 1924 the first successful blowout preventer was brought to market.^[6] The BOP valve affixed to the wellhead could be closed in the event of drilling into a high pressure zone, and the well fluids contained. Well control techniques could be used to regain control of the well. As the technology developed, blowout preventers became standard equipment, and gushers became a thing of the past.

In the modern petroleum industry, uncontrollable wells became known as blowouts and are comparatively rare. There has been significant improvement in technology, well control techniques, and personnel training which has helped to prevent their occurring.^[1] From 1976 to 1981, 21 blowout reports are available.^[1]

Notable gushers

• A blowout in 1815 resulted from an attempt to drill for salt rather than for oil. Joseph Eichar and his team were digging west of the town of Wooster, Ohio, US along Killbuck Creek, when they struck oil. In a written retelling by Eichar's daughter, Eleanor, the strike produced "a spontaneous outburst, which shot up high as the tops of the highest trees!"^[7]
• Oil drillers struck a number of gushers near Oil City, Pennsylvania, US in 1861. The most famous was the Little & Merrick well, which began gushing oil on 17 April 1861. The spectacle of the fountain of oil flowing out at about 3,000 barrels (480 m³) per day had drawn about 150 spectators by the time an hour later when the oil gusher burst into flames, raining fire down on the oil-soaked onlookers. Thirty people died. Other early gushers in northwest Pennsylvania were the Phillips #2 (4,000 barrels (640 m³) per day) in September 1861, and the Woodford well (3,000 barrels (480 m³) per day) in December 1861.^[8]
• The Shaw Gusher in Oil Springs, Ontario, was Canada's first oil gusher. On January 16, 1862, it shot oil from over 60 metres (200 ft) below ground to above the treetops at a rate of 3,000 barrels (480 m³) per day, triggering the oil boom in Lambton County.^[9]
• Lucas Gusher at Spindletop in Beaumont, Texas, US in 1901 flowed at 100,000 barrels (16,000 m³) per day at its peak, but soon slowed and was capped within nine days. The well tripled U.S. oil production overnight and marked the start of the Texas oil industry.^[10][11]
• Masjed Soleiman, Iran, in 1908 marked the first major oil strike recorded in the Middle East.^[12]
• Dos Bocas in the State of Veracruz, Mexico, was a famous 1908 Mexican blowout that formed a large crater. It leaked oil from the main reservoir for many years, continuing even after 1938 (when Pemex nationalized the Mexican oil industry).
• Lakeview Gusher on the Midway-Sunset Oil Field in Kern County, California, US of 1910 is believed to be the largest-ever U.S. gusher. At its peak, more than 100,000 barrels (16,000 m³) of oil per day flowed out, reaching as high as 200 feet (61 m) in the air. It remained uncapped for 18 months, spilling over 9 million barrels (1,400,000 m³) of oil, less than half of which was recovered.^[2]
• A short-lived gusher at Alamitos #1 in Signal Hill, California, US in 1921 marked the discovery of the Long Beach Oil Field, one of the most productive oil fields in the world.^[13]
• The Barroso 2 well in Cabimas, Venezuela, in December 1922 flowed at around 100,000 barrels (16,000 m³) per day for nine days, plus a large amount of natural gas.^[14]
• Baba Gurgur near Kirkuk, Iraq, an oilfield known since antiquity, erupted at a rate of 95,000 barrels (15,100 m³) a day in 1927.^[15]
• The Yates #30-A in Pecos County, Texas, US gushing 80 feet through the fifteen-inch casing, produced a world record 204,682 barrels of oil a day from a depth of 1,070 feet on 23 September 1929.^[16]
• The Wild Mary Sudik gusher in Oklahoma City, Oklahoma, US in 1930 flowed at a rate of 72,000 barrels (11,400 m³) per day.^[17]
• The Daisy Bradford gusher in 1930 marked the discovery of the East Texas Oil Field, the largest oilfield in the contiguous United States.^[18]
• The largest known 'wildcat' oil gusher blew near Qom, Iran, on 26 August 1956. The uncontrolled oil gushed to a height of 52 m (171 ft), at a rate of 120,000 barrels (19,000 m³) per day. The gusher was closed after 90 days' work by Bagher Mostofi and Myron Kinley (USA).^[19]
• On October 17, 1982, a sour gas well AMOCO DOME BRAZEAU RIVER 13-12-48-12, being drilled 20 km west of Lodgepole, Alberta blew out. The burning well was finally capped 67 days later by the Texas well-control company, Boots & Coots.
• One of the most troublesome gushers happened on 23 June 1985, at well #37 at the Tengiz field in Atyrau, Kazakh SSR, Soviet Union, where the 4,209-metre deep well blew out and the 200-metre high gusher self-ignited two days later. Oil pressure up to 800 atm and high hydrogen sulfide content had led to the gusher being capped only on 27 July 1986. The total volume of erupted material measured at 4.3 million metric tons of oil and 1.7 billion m³ of natural gas, and the burning gusher resulted in 890 tons of various mercaptans and more than 900,000 tons of soot released into the atmosphere.^[20]
• Deepwater Horizon explosion: The largest underwater blowout in U.S. history occurred on 20 April 2010, in the Gulf of Mexico at the Macondo Prospect oil field. The blowout caused the explosion of the Deepwater Horizon, a mobile offshore drilling platform owned by Transocean and under lease to BP at the time of the blowout. While the exact volume of oil spilled is unknown, as of June 3, 2010, the United States Geological Survey Flow Rate Technical Group has placed the estimate at between 35,000 to 60,000 barrels (5,600 to 9,500 m³) of crude oil per day.^{[21][needs update]}

Cause of blowouts

Reservoir pressure

See also: Petroleum formation

A petroleum trap. An irregularity (the trap) in a layer of impermeable rocks (the seal) retains upward-flowing petroleum, forming a reservoir.

Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights, and other organic compounds, found in geologic formations beneath the Earth's surface. Because most hydrocarbons are lighter than rock or water, they often migrate upward and occasionally laterally through adjacent rock layers until either reaching the surface or becoming trapped within porous rocks (known as reservoirs) by impermeable rocks above. When hydrocarbons are concentrated in a trap, an oil field forms, from which the liquid can be extracted by drilling and pumping. The downhole pressure in the rock structures changes depending upon the depth and the characteristics of the source rock. Natural gas (mostly methane) may be present also, usually above the oil within the reservoir, but sometimes dissolved in the oil at reservoir pressure and temperature. Dissolved gas typically comes out of solution as free gas as the pressure is reduced either under controlled production operations or in a kick, or in an uncontrolled blowout. The hydrocarbon in some reservoirs may be essentially all natural gas.

Formation kick

The downhole fluid pressures are controlled in modern wells through the balancing of the hydrostatic pressure provided by the mud column. Should the balance of the drilling mud pressure be incorrect (i.e., the mud pressure gradient is less than the formation pore pressure gradient), then formation fluids (oil, natural gas, and/or water) can begin to flow into the wellbore and up the annulus (the space between the outside of the drill string and the wall of the open hole or the inside of the casing), and/or inside the drill pipe. This is commonly called a kick. Ideally, mechanical barriers such as blowout preventers (BOPs) can be closed to isolate the well while the hydrostatic balance is regained through circulation of fluids in the well. But if the well is not shut in (common term for the closing of the blow-out preventer), a kick can quickly escalate into a blowout when the formation fluids reach the surface, especially when the influx contains gas that expands rapidly with the reduced pressure as it flows up the wellbore, further decreasing the effective weight of the fluid.

Early warning signs of an impending well kick while drilling are:

• Sudden change in drilling rate;
• Reduction in drillpipe weight;
• Change in pump pressure;
• Change in drilling fluid return rate.

Other warning signs during the drilling operation are:

• Returning mud "cut" by (i.e., contaminated by) gas, oil or water;
• Connection gases, high background gas units, and high bottoms-up gas units detected in the mudlogging unit.^[22]

The primary means of detecting a kick while drilling is a relative change in the circulation rate back up to the surface into the mud pits. The drilling crew or mud engineer keeps track of the level in the mud pits and closely monitors the rate of mud returns versus the rate that is being pumped down the drill pipe. Upon encountering a zone of higher pressure than is being exerted by the hydrostatic head of the drilling mud (including the small additional frictional head while circulating) at the bit, an increase in mud return rate would be noticed as the formation fluid influx blends in with the circulating drilling mud. Conversely, if the rate of returns is slower than expected, it means that a certain amount of the mud is being lost to a thief zone somewhere below the last casing shoe. This does not necessarily result in a kick (and may never become one); however, a drop in the mud level might allow influx of formation fluids from other zones if the hydrostatic head is reduced to less than that of a full column of mud.^{[citation needed]}

Well control

The first response to detecting a kick would be to isolate the wellbore from the surface by activating the blow-out preventers and closing in the well. Then the drilling crew would attempt to circulate in a heavier kill fluid to increase the hydrostatic pressure (sometimes with the assistance of a well control company). In the process, the influx fluids will be slowly circulated out in a controlled manner, taking care not to allow any gas to accelerate up the wellbore too quickly by controlling casing pressure with chokes on a predetermined schedule.

This effect will be minor if the influx fluid is mainly salt water. And with an oil-based drilling fluid it can be masked in the early stages of controlling a kick because gas influx may dissolve into the oil under pressure at depth, only to come out of solution and expand rather rapidly as the influx nears the surface. Once all the contaminant has been circulated out, the shut-in casing pressure should have reached zero.^{[citation needed]}

Capping stacks are used for controlling blowouts. The cap is an open valve that is closed after bolted on.^[23]

Types of blowouts

Ixtoc I oil well blowout

Well blowouts can occur during the drilling phase, during well testing, during well completion, during production, or during workover activities.^[1]

Surface blowouts

Blowouts can eject the drill string out of the well, and the force of the escaping fluid can be strong enough to damage the drilling rig. In addition to oil, the output of a well blowout might include natural gas, water, drilling fluid, mud, sand, rocks, and other substances.

Blowouts will often be ignited from sparks from rocks being ejected, or simply from heat generated by friction. A well control company then will need to extinguish the well fire or cap the well, and replace the casing head and other surface equipment. If the flowing gas contains poisonous hydrogen sulfide, the oil operator might decide to ignite the stream to convert this to less hazardous substances.^{[citation needed]}

Sometimes blowouts can be so forceful that they cannot be directly brought under control from the surface, particularly if there is so much energy in the flowing zone that it does not deplete significantly over time. In such cases, other wells (called relief wells) may be drilled to intersect the well or pocket, in order to allow kill-weight fluids to be introduced at depth. When first drilled in the 1930s relief wells were drilled to inject water into the main drill well hole.^[24] Contrary to what might be inferred from the term, such wells generally are not used to help relieve pressure using multiple outlets from the blowout zone.

Subsea blowouts

Macondo-1 well blowout on the Deepwater Horizon rig, 21 April 2010

The two main causes of a subsea blowout are equipment failures and imbalances with encountered subsurface reservoir pressure.^[25] Subsea wells have pressure control equipment located on the seabed or between the riser pipe and drilling platform. Blowout preventers (BOPs) are the primary safety devices designed to maintain control of geologically driven well pressures. They contain hydraulic-powered cut-off mechanisms to stop the flow of hydrocarbons in the event of a loss of well control.^[26]

Even with blowout prevention equipment and processes in place, operators must be prepared to respond to a blowout should one occur. Before drilling a well, a detailed well construction design plan, an Oil Spill Response Plan as well as a Well Containment Plan must be submitted, reviewed and approved by BSEE and is contingent upon access to adequate well containment resources in accordance to NTL 2010-N10.^[27]

The Deepwater Horizon well blowout in the Gulf of Mexico in April 2010 occurred at a 5,000 feet (1,500 m) water depth.^[28] Current blowout response capabilities in the U.S. Gulf of Mexico meet capture and process rates of 130,000 barrels of fluid per day and a gas handling capacity of 220 million cubic feet per day at depths through 10,000 feet.^[29]

Underground blowouts

An underground blowout is a special situation where fluids from high pressure zones flow uncontrolled to lower pressure zones within the wellbore. Usually this is from deeper higher pressure zones to shallower lower pressure formations. There may be no escaping fluid flow at the wellhead. However, the formation(s) receiving the influx can become overpressured, a possibility that future drilling plans in the vicinity must consider.^{[citation needed]}

Blowout control companies

Myron M. Kinley was a pioneer in fighting oil well fires and blowouts. He developed many patents and designs for the tools and techniques of oil firefighting. His father, Karl T. Kinley, attempted to extinguish an oil well fire with the help of a massive explosion—a method still in common use for fighting oil fires. Myron and Karl Kinley first successfully used explosives to extinguish an oil well fire in 1913.^[30] Kinley would later form the M. M. Kinley Company in 1923.^[30] Asger "Boots" Hansen and Edward Owen "Coots" Matthews also begin their careers under Kinley.

Paul N. "Red" Adair joined the M. M. Kinley Company in 1946, and worked 14 years with Myron Kinley before starting his own company, Red Adair Co., Inc., in 1959.

Red Adair Co. has helped in controlling offshore blowouts, including:

• CATCO fire in the Gulf of Mexico in 1959
• "The Devil's Cigarette Lighter" in 1962 in Gassi Touil, Algeria, in the Sahara Desert
• The Ixtoc I oil spill in Mexico's Bay of Campeche in 1979
• The Piper Alpha disaster in the North Sea in 1988
• The Kuwaiti oil fires following the Gulf War in 1991.^[31]

The 1968 American film, Hellfighters, which starred John Wayne, is about a group of oil well firefighters, based loosely on Adair's life; Adair, Hansen, and Matthews served as technical advisors on the film.

In 1994, Adair retired and sold his company to Global Industries. Management of Adair's company left and created International Well Control (IWC). In 1997, they would buy the company Boots & Coots International Well Control, Inc., which was founded by Hansen and Matthews in 1978.

Methods of quenching blowouts

Subsea Well Containment

Government Accountability Office diagram showing subsea well containment operations

After the Macondo-1 blowout on the Deepwater Horizon, the offshore industry collaborated with government regulators to develop a framework to respond to future subsea incidents. As a result, all energy companies operating in the deep-water U.S. Gulf of Mexico must submit an OPA 90 required Oil Spill Response Plan with the addition of a Regional Containment Demonstration Plan prior to any drilling activity.^[32] In the event of a subsea blowout, these plans are immediately activated, drawing on some of the equipment and processes effectively used to contain the Deepwater Horizon well as others that have been developed in its aftermath.

In order to regain control of a subsea well, the Responsible Party would first secure the safety of all personnel on board the rig and then begin a detailed evaluation of the incident site. Remotely operated underwater vehicles (ROVs) would be dispatched to inspect the condition of the wellhead, Blowout Preventer (BOP) and other subsea well equipment. The debris removal process would begin immediately to provide clear access for a capping stack.

Once lowered and latched on the wellhead, a capping stack uses stored hydraulic pressure to close a hydraulic ram and stop the flow of hydrocarbons.^[33] If shutting in the well could introduce unstable geological conditions in the wellbore, a cap and flow procedure would be used to contain hydrocarbons and safely transport them to a surface vessel.^[34]

The Responsible Party works in collaboration with BSEE and the United States Coast Guard to oversee response efforts, including source control, recovering discharged oil and mitigating environmental impact.^[35]

Several not-for-profit organizations provide a solution to effectively contain a subsea blowout. HWCG LLC and Marine Well Containment Company operate within the U.S. Gulf of Mexico^[36] waters, while cooperatives like Oil Spill Response Limited offer support for international operations.

Use of nuclear explosions

On Sep. 30, 1966, the Soviet Union experienced blowouts on five natural gas wells in Urta-Bulak, an area about 80 kilometers from Bukhara, Uzbekistan. It was claimed in Komsomoloskaya Pravda that after years of burning uncontrollably they were able to stop them entirely.^[37] The Soviets lowered a specially made 30 kiloton nuclear physics package into a 6-kilometre (20,000 ft) borehole drilled 25 to 50 metres (82 to 164 ft) away from the original (rapidly leaking) well. A nuclear explosive was deemed necessary because conventional explosives both lacked the necessary power and would also require a great deal more space underground. When the device was detonated, it crushed the original pipe that was carrying the gas from the deep reservoir to the surface and vitrified the surrounding rock. This caused the leak and fire at the surface to cease within approximately one minute of the explosion, and proved to be a permanent solution. An attempt on a similar well was not as successful. Other tests were for such experiments as oil extraction enhancement (Stavropol, 1969) and the creation of gas storage reservoirs (Orenburg, 1970).^[38]

Notable offshore well blowouts

Data from industry information.^[1][39]

Year	Rig Name	Rig Owner	Type	Damage / details
1955	S-44	Chevron Corporation	Sub Recessed pontoons	Blowout and fire. Returned to service.
1959	C. T. Thornton	Reading & Bates	Jackup	Blowout and fire damage.
1964	C. P. Baker	Reading & Bates	Drill barge	Blowout in Gulf of Mexico, vessel capsized, 22 killed.
1965	Trion	Royal Dutch Shell	Jackup	Destroyed by blowout.
1965	Paguro	SNAM	Jackup	Destroyed by blowout and fire.
1968	Little Bob	Coral	Jackup	Blowout and fire, killed 7.
1969	Wodeco III	Floor drilling	Drilling barge	Blowout
1969	Sedco 135G	Sedco Inc	Semi-submersible	Blowout damage
1969	Rimrick Tidelands	ODECO	Submersible	Blowout in Gulf of Mexico
1970	Stormdrill III	Storm Drilling	Jackup	Blowout and fire damage.
1970	Discoverer III	Offshore Co.	Drillship	Blowout (S. China Seas)
1971	Big John	Atwood Oceanics	Drill barge	Blowout and fire.
1971	Wodeco II	Floor Drilling	Drill barge	Blowout and fire off Peru, 7 killed.[citation needed]
1972	J. Storm II	Marine Drilling Co.	Jackup	Blowout in Gulf of Mexico
1972	M. G. Hulme	Reading & Bates	Jackup	Blowout and capsize in Java Sea.
1972	Rig 20	Transworld Drilling	Jackup	Blowout in Gulf of Martaban.
1973	Mariner I	Santa Fe Drilling	Semi-sub	Blowout off Trinidad, 3 killed.
1975	Mariner II	Santa Fe Drilling	Semi-submersible	Lost BOP during blowout.
1975	J. Storm II	Marine Drilling Co.	Jackup	Blowout in Gulf of Mexico.[citation needed]
1976	Petrobras III	Petrobras	Jackup	No info.
1976	W. D. Kent	Reading & Bates	Jackup	Damage while drilling relief well.[citation needed]
1977	Maersk Explorer	Maersk Drilling	Jackup	Blowout and fire in North Sea[citation needed]
1977	Ekofisk Bravo	Phillips Petroleum	Platform	Blowout during well workover.[40]
1978	Scan Bay	Scan Drilling	Jackup	Blowout and fire in the Persion Gulf.[citation needed]
1979	Salenergy II	Salen Offshore	Jackup	Blowout in Gulf of Mexico
1979	Sedco 135	Sedco Drilling	Semi-submersible	Blowout and fire in Bay of Campeche Ixtoc I well.[41]
1980	Sedco 135C	Sedco Drilling	Semi-submersible	Blowout and fire of Nigeria.
1980	Discoverer 534	Offshore Co.	Drillship	Gas escape caught fire.[citation needed]
1980	Ron Tappmeyer	Reading & Bates	Jackup	Blowout in Persian Gulf, 5 killed.[citation needed]
1980	Nanhai II	People's Republic of China	Jackup	Blowout of Hainan Island.[citation needed]
1980	Maersk Endurer	Maersk Drilling	Jackup	Blowout in Red Sea, 2 killed.[citation needed]
1980	Ocean King	ODECO	Jackup	Blowout and fire in Gulf of Mexico, 5 killed.[42]
1980	Marlin 14	Marlin Drilling	Jackup	Blowout in Gulf of Mexico[citation needed]
1981	Penrod 50	Penrod Drilling	Submersible	Blowout and fire in Gulf of Mexico.[citation needed]
1984	Plataforma Central de Enchova	Petrobras	fixed platform	Blowout and fire in Campos Basin, Rio de Janeiro, Brazil, 37 fatalities.
1985	West Vanguard	Smedvig	Semi-submersible	Shallow gas blowout and fire in Norwegian sea, 1 fatality.
1981	Petromar V	Petromar	Drillship	Gas blowout and capsize in S. China seas.[citation needed]
1983	Bull Run	Atwood Oceanics	Tender	Oil and gas blowout Dubai, 3 fatalities.
1988	Ocean Odyssey	Diamond Offshore Drilling	Semi-submersible	Gas blowout at BOP and fire in the UK North Sea, 1 killed.
1988	Plataforma Central de Enchova	Petrobras	fixed platform	Blowout and fire in Campos Basin, Rio de Janeiro, Brazil, no fatality, platform entirely destroyed.
1989	Al Baz	Santa Fe	Jackup	Shallow gas blowout and fire in Nigeria, 5 killed.[43]
1993	M. Naqib Khalid	Naqib Co.	Naqib Drilling	fire and explosion. Returned to service.
1993	Actinia	Transocean	Semi-submersible	Sub-sea blowout in Vietnam.[44]
2001	Ensco 51	Ensco	Jackup	Gas blowout and fire, Gulf of Mexico, no casualties[45]
2002	Arabdrill 19	Arabian Drilling Co.	Jackup	Structural collapse, blowout, fire and sinking.[46]
2004	Adriatic IV	Global Santa Fe	Jackup	Blowout and fire at Temsah platform, Mediterranean Sea[47]
2007	Usumacinta	PEMEX	Jackup	Storm forced rig to move, causing well blowout on Kab 101 platform, 22 killed.[48]
2009	West Atlas / Montara	Seadrill	Jackup / Platform	Blowout and fire on rig and platform in Australia.[49]
2010	Deepwater Horizon	Transocean	Semi-submersible	Blowout and fire on the rig, subsea well blowout, killed 11 in explosion.
2010	Vermilion Block 380	Mariner Energy	Platform	Blowout and fire, 13 survivors, 1 injured.[50][51]
2012	KS Endeavour	KS Energy Services	Jack-Up	Blowout and fire on the rig, collapsed, killed 2 in explosion.
2012	Elgin platform	Total	Platform	Blowout and prolonged sour gas release, no injuries.

See also

• Drilling fluid
• Drilling rig
• List of oil spills
• Oil platform
• Oil well
• Oil well control
• Oil well fire
• Petroleum geology
• Underbalanced drilling

References

1. 
   

'All About Blowout', R. Westergaard, Norwegian Oil Review, 1987 ISBN 82-991533-0-1

"www.sjgs.com". www.sjgs.com. Archived from the original on 2006-10-19. Retrieved 2016-01-30.

Walsh, Bryan (2010-05-19). "Gulf Oil Spill: Scientists Escalate Environmental Warnings". Time. Archived from the original on June 29, 2010. Retrieved June 30, 2010.

"Hughes McKie Oil Well Explosion". Rootsweb.com. 1923-05-08. Archived from the original on 2008-02-25. Retrieved 2016-01-30.

"Ending Oil Gushers – BOP |". Aoghs.org. Archived from the original on 2016-01-31. Retrieved 2016-01-30.

"Engineering History". Asme.org. 1905-03-10. Archived from the original on 2010-12-26. Retrieved 2016-01-30.

Douglass, Ben (1878). "Chapter XVI". History of Wayne County, Ohio, from the Days of the First Settlers to the Present Time. Indianapolis, Ind.: Robert Douglass, publisher. pp. 233–235. OCLC 4721800. Retrieved 2013-07-16. One of the greatest obstacles they met with when boring was the striking a strong vein of oil, a spontaneous outburst, which shot up high as the tops of the highest trees!

The Derrick's Hand-Book of Petroleum (Oil City, Penn.: Derrick Publishing, 1898) 20–24.

"The Shaw Gusher". The Village of Oil Springs. Archived from the original on 2009-12-06. Retrieved 2011-02-23.

"www.sjgs.com". www.sjgs.com. Archived from the original on 2016-02-02. Retrieved 2016-01-30.

Wooster, Robert; Sanders, Christine Moor: Spindletop Oilfield from the Handbook of Texas Online. Retrieved October 18, 2009., Texas State Historical Association

Ian Ellis. "May 26 – Today in Science History – Scientists born on May 26th, died, and events". Todayinsci.com. Archived from the original on 2015-05-29. Retrieved 2016-01-30.

"The City of Signal Hill -- Official Web Site -- Signal Hill, California". Archived from the original on 2007-09-29. Retrieved 2010-05-18.

http://www.propuestas.reacciun.ve/Servidor_Tematico_Petroleo/documentos_articulos6.html#petroleo7^{[permanent dead link]}

"Paragraphs". Archived from the original on 2009-05-24. Retrieved 2010-05-18.

Rundell, Walter.p (1982). Oil in West Texas and New Mexico : a pictorial history of the Permian Basin (1st ed.). College Station: Published for the Permian Basin Petroleum Museum Library, and Hall of Fame, Midland, Texas, by Texas A & M University Press. p. 89. ISBN 0-89096-125-5. OCLC 8110608.

Whipple, Tom (2005-03-15). "Full steam ahead for BC offshore oil drilling". Energybulletin.net. Archived from the original on 2008-01-20. Retrieved 2016-01-30.

"East Texas Oil Museum at Kilgore College – History". Easttexasoilmuseum.com. 1930-10-03. Archived from the original on 2016-02-08. Retrieved 2016-01-30.

Norris Mcwhirter; Donald McFarlan (1989). the Guinness Book of Records 1990. Guinness Publishing Ltd. ISBN 978-0-85112-341-7. Archived from the original on 2018-05-03.

Christopher Pala (2001-10-23). "Kazakhstan Field's Riches Come With a Price". Vol. 82, no. 715. The St. Petersburg Times. Archived from the original on 2013-12-28. Retrieved 2009-10-12.

"Oil estimate raised to 35,000–60,000 barrels a day". CNN. 2010-06-15. Archived from the original on 2010-06-16. Retrieved 2010-06-15.

Grace, R: Blowout and Well Control Handbook, page 42. Gulf Professional Publishing, 2003

"Blowout Control, Part 10 – Surface Intervention Methods". Jwco.com. Archived from the original on 2016-02-03. Retrieved 2016-01-30.

"Wild Oil Well Tamed by Scientific Trick" Popular Mechanics, July 1934 Archived 2018-05-03 at the Wayback Machine

"How Does Subsea Well Containment and Incident Response Work?". Rigzone. Archived from the original on 2015-04-18.

"Drilling Blowout Preventers". United States Department of Labor. Archived from the original on 2015-06-30.

"NTL No. 2010-N10". BSEE.gov. US Department of the Interior Bureau of Ocean Energy Management, Regulation and Enforcement. Archived from the original on 2015-09-30.

"Macondo Prospect, Gulf of Mexico, United States of America". Offshore Technology. Archived from the original on 2012-04-26.

"HWCG Expands Capabilities to Minimize Potential Impact of a Deepwater Incident". HWCG.org. Archived from the original on 2016-03-04. Retrieved 2015-09-09.

Boots & Coots History Page : "Boots & Coots International Well Control, Inc". Archived from the original on 2010-05-26. Retrieved 2010-05-21.

"redadair.com". www.redadair.com. Archived from the original on 17 July 2008. Retrieved 3 May 2018.

"Guidance to Owners and Operators of Offshore Facilities Seaward of the Coast Line Concerning Regional Oil Spill Response Plans (NTL No. 2012-N06)" (PDF). BSEE.gov. Bureau of Safety and Environmental Enforcement. Archived from the original (PDF) on 2016-03-05.

Madrid, Mauricio; Matson, Anthony (2014). "How Offshore Capping Stacks Work" (PDF). Society of Petroleum Engineers: The Way Ahead. 10 (1). Archived (PDF) from the original on 2015-11-29.

"How Does Subsea Well Containment and Incident Response Work?". Rigzone.com. Rigzone. Archived from the original on 2015-09-09.

"Memoranda of Agreement Between the Bureau of Safety and Environmental Enforcement and U.S. Coast Guard (MOA: OCS-03)". BSEE/USCG. Archived from the original on 2015-04-25.

"Deepwater Horizon Spurs Development of Spill Prevention Systems". Rigzone. April 20, 2011. Archived from the original on September 8, 2015.

"Google Translate". Komsomoloskaya Pravda. 3 May 2010. Retrieved 3 May 2018.

CineGraphic (4 July 2009). "An Atomic Bomb will stop the Gulf Oil Leak, LOOK!". Archived from the original on 7 November 2017. Retrieved 3 May 2018 – via YouTube.

Rig disaster Website : "Worst Offshore Blowouts - Oil Rig Disasters - Offshore Drilling Accidents". Archived from the original on 2014-12-28. Retrieved 2013-04-05.

Oil Rig Disasters Website : "IXTOC I Blowout and Sedco 135F - Oil Rig Disasters - Offshore Drilling Accidents". Archived from the original on 2010-12-03. Retrieved 2010-05-23.

"Matter of Sedco, Inc., 543 F. Supp. 561 (S.D. Tex. 1982)". justia.com. Archived from the original on 7 October 2017. Retrieved 3 May 2018.

"813 F2d 679 Incident Aboard D/b Ocean King on August Cities Service Company v. Ocean Drilling & Exploration Co Getty Oil Co". OpenJurist. 1987-04-01. p. 679. Archived from the original on 2016-03-03. Retrieved 2016-01-30.

Rig Disaster Website : "Santa Fe al Baz Blowout - Oil Rig Disasters - Offshore Drilling Accidents". Archived from the original on 2010-12-04. Retrieved 2010-05-23.

"Actinia Blowout – Oil Rig Disasters – Offshore Drilling Accidents". Home.versatel.nl. Archived from the original on 2016-03-03. Retrieved 2016-01-30.

Oil Rig Disasters website : "Ensco 51 Blowout - Oil Rig Disasters - Offshore Drilling Accidents". Archived from the original on 2010-06-19. Retrieved 2010-05-29.

Oil Rig Disasters Website : "Arabdrill 19 AD19 - Oil Rig Disasters - Offshore Drilling Accidents". Archived from the original on 2010-12-04. Retrieved 2010-09-21.

Oil Rig Disasters Website : "GSF Adriatic IV - Oil Rig Disasters - Offshore Drilling Accidents". Archived from the original on 2010-12-04. Retrieved 2010-05-23.

Usumacinta website : "Usumacinta and Kab 101 Blowout - Oil Rig Disasters - Offshore Drilling Accidents". Archived from the original on 2014-10-11. Retrieved 2014-10-11.

ABC

September 2 oil rig explosion Archived 2010-09-03 at the Wayback Machine, CNN

51. New oil rig explosion in Gulf of Mexico Archived 2010-09-05 at the Wayback Machine WFRV

External links

• San Joaquin Geological Society article on famous Californian gushers
• "Blowout Control, Part 10 – Surface Intervention Methods". Retrieved 2010-06-19.

v t e Petroleum industry
Petroleum Primary energy
Benchmarks	Argus Sour Bonny Light Brent Dubai Indian Basket Indonesian Isthmus-34 Light Japan Cocktail OPEC Reference Basket Tapis Urals West Texas Intermediate Western Canadian Select
Data	Natural gas Consumption Production Reserves Imports Exports Price Petroleum Consumption Production Reserves Imports Exports Price of gasoline and diesel Posted price
Exploration	Core sampling Geophysics Integrated asset modelling Petroleum engineering Reservoir simulation Seismic to simulation Petroleum geology Petrophysics Reflection seismology Seismic inversion Seismic source
Drilling	Blowout Completion Squeeze job Differential sticking Directional drilling Geosteering Drilling engineering Drilling fluid invasion Drill stem test Lost circulation Measurement Tracers Shale oil extraction Ljungström method Underbalanced drilling Well logging
Production	Petroleum fiscal regime Concessions Production sharing agreements Artificial lift Pumpjack Submersible pump (ESP) Gas lift Downstream Enhanced oil recovery (EOR) Steam injection Gas reinjection Midstream Petroleum product Pipeline transport Refining Upstream Water injection Well intervention XT
History	1967 Oil Embargo 1973 oil crisis 1979 energy crisis 1980s oil glut 1990 oil price shock 2000s energy crisis 2010s oil glut 2020 oil price war Founders History of the petroleum industry Nationalization OPEC GECF Seven Sisters Standard Oil Oil market timelines Petroleum industry in Iraq
Provinces and fields	List of natural gas fields List of oil fields Caspian Sea East Midlands Oil Province East Texas Gulf of Mexico Niger Delta North Sea Permian Basin Persian Gulf Prudhoe Bay Russia Venezuela Western Canadian Sedimentary Basin
Other topics	Acronyms Abandoned or orphan wells Oil shale gas Peak oil mitigation timing People Petrocurrency Petrodollar recycling Petrofiction Shale band Shale gas Swing producer Unconventional oil heavy crude oil sands oil shale tight oil Classification sweet oil sour oil
Companies and organisations	Major petroleum companies Supermajors BP Chevron Eni ExxonMobil Shell TotalEnergies National oil companies ADNOC ANCAP Bharat Petroleum CNOOC CNPC Ecopetrol Equinor Gazprom Hindustan Petroleum Iraq National Oil Company Indian Oil Corporation KazMunayGas Kuwait Petroleum Corporation Lotos Naftogaz Nigerian National Petroleum Corporation NIOC NISOC OGDCL ONGC PDVSA PKN Orlen Pemex Pertamina Petrobangla Petrobras PetroChina Petronas Petrovietnam PTT QatarEnergy Rosneft Saudi Aramco Sinopec SOCAR Sonangol Sonatrach TPAO YPF Energy trading Enron Glencore Gunvor Mercuria Naftiran Intertrade Trafigura Vitol Others APA Cenovus Energy Compañía Española de Petróleos ConocoPhillips Devon Eneos Holdings Galp Energia Hess Husky Energy Imperial Oil Lukoil Marathon Oil Marathon Petroleum Occidental Petroleum OMV Phillips 66 Port Harcourt Refining Company Reliance Industries Repsol Suncor Energy Sunoco Surgutneftegas TechnipFMC TNK-BP Tullow Oil Tüpraş Valero Energy Major services companies Amec Foster Wheeler Baker Hughes Cameron CGG CH2M Hill Chicago Bridge & Iron Company China Oilfield Services Enbridge GE Power Halliburton Nabors Industries Naftiran Intertrade NOV Petrofac Saipem Schlumberger Snam Subsea 7 TC Energy Transocean Valaris Weatherford John Wood Group Others American Petroleum Institute Canadian Petroleum Companies International Association of Oil & Gas Producers International Energy Agency International Petroleum Exchange OPEC Society of Petroleum Engineers World Petroleum Council
Category Commons

Categories:

• Oil spills
• Petroleum geology
• Oil wells

https://en.wikipedia.org/wiki/Blowout_(well_drilling)

https://en.wikipedia.org/wiki/Blowout_(well_drilling)

https://en.wikipedia.org/wiki/Reflection_seismology

https://en.wikipedia.org/wiki/Reservoir_modeling#Seismic_to_simulation

https://en.wikipedia.org/wiki/Predicting_the_timing_of_peak_oil

https://en.wikipedia.org/wiki/Oil_shale_gas

https://en.wikipedia.org/wiki/Orphan_wells

https://en.wikipedia.org/wiki/Shale_gas

https://en.wikipedia.org/wiki/Unconventional_(oil_%26_gas)_reservoir

https://en.wikipedia.org/wiki/Oil_reserves_in_Russia

https://en.wikipedia.org/wiki/Niger_Delta#Nigerian_oil

https://en.wikipedia.org/wiki/Caspian_Sea

https://en.wikipedia.org/wiki/1973_oil_crisis

https://en.wikipedia.org/wiki/1967_Oil_Embargo

https://en.wikipedia.org/wiki/Well_logging

https://en.wikipedia.org/wiki/Underbalanced_drilling

https://en.wikipedia.org/wiki/Differential_sticking

https://en.wikipedia.org/wiki/Drilling_fluid_invasion

https://en.wikipedia.org/wiki/Dust_Bowl

https://en.wikipedia.org/wiki/Pedioplanis_lineoocellata

https://en.wikipedia.org/wiki/Rock_Sand

https://en.wikipedia.org/wiki/Utabaenetes

https://en.wikipedia.org/wiki/Phlebotomus

https://en.wikipedia.org/wiki/Great_cormorant

https://en.wikipedia.org/wiki/Sea_glass#Antique_black_sea_glass

https://en.wikipedia.org/wiki/Podalonia_hirsuta

https://en.wikipedia.org/wiki/Schwarzwaldhochstra%C3%9Fe

Long sand racer
Subadult Psammophis longifrons

https://en.wikipedia.org/wiki/Psammophis_longifrons

https://en.wikipedia.org/wiki/Phaethontis_quadrangle

From Wikipedia, the free encyclopedia

(Redirected from Sand crepe)

For other uses, see Crepe (disambiguation).

Woman's mourning bonnet in hard crape, c. 1880

Crêpe, also spelled crepe or crape (from the French crêpe)^[1] is a silk, wool, or synthetic fiber fabric with a distinctively crisp and crimped appearance. The term "crape" typically refers to a form of the fabric associated specifically with mourning.^[2] Crêpe was also historically called "crespe" or "crisp".^[3]

It is woven of hard-spun yarn, originally silk "in the gum" (silk from which the sericin had not been removed). There traditionally have been two distinct varieties of the crêpe: soft, Canton or Oriental crêpe, and hard or crisped crêpe.^[4] 

https://en.wikipedia.org/wiki/Cr%C3%AApe_(textile)

 

https://en.wikipedia.org/wiki/List_of_medically_significant_spider_bites#Six-eyed_sand_spiders

https://en.wikipedia.org/wiki/Lophius

https://en.wikipedia.org/wiki/Silver_(color)#Silver_sand

https://en.wikipedia.org/wiki/Crazy_Horse

https://en.wikipedia.org/wiki/Dark-shouldered_snake_eel

https://en.wikipedia.org/wiki/Film_noir

https://en.wikipedia.org/wiki/Black_saw-wing

https://en.wikipedia.org/wiki/Sandhill_crane

https://en.wikipedia.org/wiki/Rub%27_al_Khali

https://en.wikipedia.org/wiki/Hyoscyamus_niger

https://en.wikipedia.org/wiki/Wycliffe%27s_Bible

https://en.wikipedia.org/wiki/Black-necked_stork

https://en.wikipedia.org/wiki/Visceral_leishmaniasis

https://en.wikipedia.org/wiki/Glass_casting#Sand_casting

https://en.wikipedia.org/wiki/Austrosimulium_australense

https://en.wikipedia.org/wiki/Ribbon_eel

 https://en.wikipedia.org/wiki/Flathead_grey_mullet

https://en.wikipedia.org/wiki/Dutch_oven

https://en.wikipedia.org/wiki/Steatoda_capensis

https://en.wikipedia.org/wiki/Platycephalus_fuscus

https://en.wikipedia.org/wiki/Merlangius

https://en.wikipedia.org/wiki/Spindletop

https://en.wikipedia.org/wiki/Sodium_silicate#Sand_casting

https://en.wikipedia.org/wiki/Blackfoot_Confederacy

Proportion of Jewish population in Africa

https://en.wikipedia.org/wiki/History_of_the_Jews_in_Africa

 

https://en.wikipedia.org/wiki/Sagebrush

For other uses, see Alfalfa (disambiguation).

Alfalfa
Medicago sativa[1]
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Rosids
Order:	Fabales
Family:	Fabaceae
Subfamily:	Faboideae
Genus:	Medicago
Section:	M. sect. Medicago
Species:	M. sativa
Binomial name
Medicago sativa L.[2]
Subspecies
M. sativa subsp. ambigua (Trautv.) Tutin M. sativa subsp. microcarpa Urban M. sativa subsp. sativa M. sativa subsp. varia (T. Martyn) Arcang.
Synonyms[3]

List

A close up of alfalfa sprouts, which are commonly used as a garnish on soups or as a filling in sandwiches and salads.

Alfalfa (/ælˈfælfə/) (Medicago sativa), also called lucerne, is a perennial flowering plant in the legume family Fabaceae. It is cultivated as an important forage crop in many countries around the world. It is used for grazing, hay, and silage, as well as a green manure and cover crop. The name alfalfa is used in North America. The name lucerne is the more commonly used name in the United Kingdom, South Africa, Australia, and New Zealand. The plant superficially resembles clover (a cousin in the same family), especially while young, when trifoliate leaves comprising round leaflets predominate. Later in maturity, leaflets are elongated. It has clusters of small purple flowers followed by fruits spiralled in 2 to 3 turns containing 10–20 seeds. Alfalfa is native to warmer temperate climates. It has been cultivated as livestock fodder since at least the era of the ancient Greeks and Romans. 

https://en.wikipedia.org/wiki/Alfalfa

Walterinnesia
Walterinnesia aegyptia
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Elapidae
Genus:	Walterinnesia Lataste, 1887
Species
Walterinnesia aegyptia Lataste, 1887 Walterinnesia morgani (Mocquard, 1905)

Walterinnesia is a genus of venomous snakes in the family Elapidae. The genus contains two species, known commonly as desert black snakes or black desert cobras, which are endemic to the Middle East.^[1] The generic name Walterinnesia honours Walter Francis Innes Bey (1858–1937), who was a physician and zoologist in Egypt.^[2] 

https://en.wikipedia.org/wiki/Walterinnesia

 

https://en.wikipedia.org/wiki/Delta_dimidiatipenne

https://en.wikipedia.org/wiki/Thar_coalfield

https://en.wikipedia.org/wiki/Salak

https://en.wikipedia.org/wiki/Synodus_intermedius

https://en.wikipedia.org/wiki/Black_Forest_National_Park

https://en.wikipedia.org/wiki/Casting

https://en.wikipedia.org/wiki/List_of_ergs

https://en.wikipedia.org/wiki/Indian_skimmer

https://en.wikipedia.org/wiki/Carreras_Cigarette_Factory

https://en.wikipedia.org/wiki/Masonry_oven

https://en.wikipedia.org/wiki/History_of_gunpowder

https://en.wikipedia.org/wiki/Glass

https://en.wikipedia.org/wiki/Citharichthys

 

Milk snake
Red milk snake (Lampropeltis triangulum syspila)
Conservation status
Least Concern (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Colubridae
Genus:	Lampropeltis
Species:	L. triangulum
Binomial name
Lampropeltis triangulum (Lacépède, 1788)[2]
Subspecies
24 subspecies, see text
Synonyms
Coluber triangulum Lacépède, 1788 Pseudoëlaps Y Berthold, 1843 Ablabes triangulum — A.M.C. Duméril & Bibron, 1854 Lampropeltis triangula — Cope, 1860 Coronella triangulum — Boulenger, 1894 Osceola doliata triangula — Cope, 1900

The milk snake or milksnake (Lampropeltis triangulum), is a species of kingsnake; 24 subspecies are currently recognized. Lampropeltis elapsoides, the scarlet kingsnake, was formerly classified as a 25th subspecies (L. t. elapsoides), but is now recognized as a distinct species.^[2] The subspecies have strikingly different appearances, and many of them have their own common names. Some authorities suggest that this species could be split into several separate species.^[2] They are not venomous to humans.^[3][4] 

https://en.wikipedia.org/wiki/Milk_snake

Photomicrograph of a feldspathic wacke (sandstone). Top image is in plane polarized light (PPL); bottom image is in cross polarized light (XPL). Blue epoxy fills pore spaces.

Photomicrograph of a lithic wacke (sandstone). Top image is in plane polarized light (PPL); bottom image is in cross polarized light (XPL). Blue epoxy fills pore spaces.

Greywacke or graywacke (German grauwacke, signifying a grey, earthy rock) is a variety of sandstone generally characterized by its hardness, dark color, and poorly sorted angular grains of quartz, feldspar, and small rock fragments or lithic fragments set in a compact, clay-fine matrix. It is a texturally immature sedimentary rock generally found in Paleozoic strata. The larger grains can be sand- to gravel-sized, and matrix materials generally constitute more than 15% of the rock by volume. The term "greywacke" can be confusing, since it can refer to either the immature (rock fragment) aspect of the rock or its fine-grained (clay) component. 

https://en.wikipedia.org/wiki/Greywacke

Eastern kingsnake
Conservation status
Least Concern (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Colubridae
Genus:	Lampropeltis
Species:	L. getula
Binomial name
Lampropeltis getula (Linnaeus, 1766)
Synonyms[2]
Coluber getulus Linnaeus, 1766 Ophibolus getulus — Baird & Girard, 1853 Coronella Getulus — A.M.C. Duméril, Bibron & A.H.A. Duméril, 1854 Ophibolus getulus — Cope, 1875 Ophilobus [sic] getulus — Cope, 1892 (ex errore) Coronella getula — Boulenger, 1894 Triaeniopholis arenarius F. Werner, 1924 Lampropeltis getula goini Neill & Allen, 1949 Lampropeltis getula — Stebbins, 1985 Lampropeltis getula — Conant & Collins, 1991 Lampropeltis getula — Liner, 1994

Lampropeltis getula, commonly known as the eastern kingsnake,^[3] common kingsnake,^[4] or chain kingsnake,^[5] is a harmless colubrid species endemic to the United States and Mexico. It has long been a favorite among collectors.^[5] Nine subspecies are currently recognized, including the nominate subspecies described here.^[6] 

https://en.wikipedia.org/wiki/Lampropeltis_getula

Astolfo and Caligorante

Astolfo (also Astolpho, Estous, and Estouls) is a fictional character in the Matter of France where he is one of Charlemagne's paladins. He is the son of Otto, the King of England (possibly referring to Charles' contemporary Offa of Mercia), and is a cousin to Orlando and Rinaldo, and a descendant of Charles Martel. While Astolfo's name appeared in the Old French chanson de geste The Four Sons of Aymon, his first major appearance was in the anonymous early fourteenth-century Franco-Venetian epic poem La Prise de Pampelune.^[1] He was subsequently a major character (typically humorous) in Italian Renaissance romance epics, such as Morgante by Luigi Pulci, Orlando Innamorato by Matteo Maria Boiardo, and Orlando Furioso by Ludovico Ariosto. 

https://en.wikipedia.org/wiki/Astolfo

 

Not to be confused with Lost lands, Ghost Island, Vanishing island, Fata Morgana (mirage), Mirage, or Null Island.

Fragment of George Powell's 1822 chart of the South Shetland Islands showing the phantom Middle Island (bottom right) in Bransfield Strait, Antarctica

The Zeno map of 1558 showing Frisland – a phantom island in the North Atlantic

The phantom island of Kianida or Cianeis in the Black Sea on a fragment of the 1467 Nicolaus Germanus edition of Ptolemy's Geography

A phantom island is a purported island which was included on maps for a period of time, but was later found not to exist. They usually originate from the reports of early sailors exploring new regions, and are commonly the result of navigational errors, mistaken observations, unverified misinformation, or deliberate fabrication. Some have remained on maps for centuries before being "un-discovered."

Unlike lost lands, which are claimed (or known) to have once existed but to have been swallowed by the sea or otherwise destroyed, a phantom island is one that is claimed to exist contemporaneously, but later found not to have existed in the first place (or found not to be an island, as with the Island of California). 

https://en.wikipedia.org/wiki/Phantom_island

Chief Saturiwa prepares his men for battle, from Plate XI of Jacques le Moyne des Morgues's engraving of Fort Caroline, Jacques le Moyne and Theodor De Bry.

Black drink is a name for several kinds of ritual beverages brewed by Native Americans in the Southeastern United States. Traditional ceremonial people of the Yuchi,^[1] Caddo,^[2] Chickasaw,^[3] Cherokee, Choctaw, Muscogee and some other Indigenous peoples of the Southeastern Woodlands use the black drink in purification ceremonies. It was occasionally known as white drink because of the association of the color white with peace leaders in some Native cultures in the Southeast.^[4]

The preparation and protocols vary between tribes and ceremonial grounds; a prominent ingredient is the roasted leaves and stems of Ilex vomitoria (commonly known as yaupon holly), a plant native to the Atlantic and Gulf Coasts. Black drink also usually contains emetic herbs.^[5] 

https://en.wikipedia.org/wiki/Black_drink

 

Bullsnake
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Colubridae
Genus:	Pituophis
Species:	P. catenifer
Subspecies:	P. c. sayi
Trinomial name
Pituophis catenifer sayi (Schlegel, 1837)
Synonyms
Coluber sayi Schlegel, 1837 Pityophis sayi sayi — Cope, 1900 Pituophis sayi — Stejneger & Barbour, 1917 Pituophis sayi sayi — Schmidt & Davis, 1941 Pituophis catenifer sayi — Wright & Wright, 1957 Pituophis melanoleucus sayi — Conant, 1975 Pituophis catenifer sayi — Collins, 1997

The bullsnake (Pituophis catenifer sayi) is a large, nonvenomous, colubrid snake. It is a subspecies of the gopher snake (Pituophis catenifer). The bullsnake is one of the largest/longest snakes of North America and the United States, reaching lengths up to 8 ft. 

https://en.wikipedia.org/wiki/Bullsnake

Pneumono­ultra­microscopic­silico­volcano­coniosis (/ˌnjuːmənoʊˌʌltrəˌmaɪkrəˈskɒpɪkˌsɪlɪkoʊvɒlˌkeɪnoʊˌkoʊniˈoʊsɪs/ (listen)^[1][2]) is a 45-letter made-up word coined in 1935 by the then president of the National Puzzlers' League, Everett M. Smith. It has sometimes been used as a synonym for the occupational disease known as silicosis, but it should not be as most silicosis is not related to mining of volcanic dusts, and no evidence of silicosis has been found in populations exposed to crystalline silica in volcanic ash. It is the longest word in the English language published in a popular dictionary, Oxford Dictionaries, which defines it as "an artificial long word said to mean a lung disease caused by inhaling very fine ash and sand dust".^[3]

Clinical and toxicological research conducted on volcanic crystalline silica has found little to no evidence of its ability to cause silicosis/pneumo­coniosis-like diseases and geochemical analyses have shown that there are inherent factors in the crystalline structure which may render volcanic crystalline silica much less pathogenic than some other forms of crystalline silica.^[4][5]

Silicosis is a form of occupational lung disease caused by inhalation of crystalline silica dust, and is marked by inflammation and scarring in the form of nodular lesions in the upper lobes of the lungs. It is a type of pneumoconiosis and is known in the United Kingdom as the “black lung”. 

https://en.wikipedia.org/wiki/Pneumonoultramicroscopicsilicovolcanoconiosis

 

Conioscinella elegans
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Diptera
Family:	Chloropidae
Subfamily:	Oscinellinae
Genus:	Conioscinella
Species:	C. elegans
Binomial name
Conioscinella elegans Becker, 1910
Synonyms
Oscinella elegans (Becker, 1910)

Conioscinella elegans is a species of eye flies in the genus of Conioscinella. It is found in Europe. 

https://en.wikipedia.org/wiki/Conioscinella_elegans

Arthropoda Temporal range: 538.8 –0 Ma PreꞒ Ꞓ O S D C P T J K Pg N Earliest Cambrian (Fortunian)–Recent
Scientific classification
Kingdom:	Animalia
Subkingdom:	Eumetazoa
Clade:	ParaHoxozoa
Clade:	Bilateria
Clade:	Nephrozoa
(unranked):	Protostomia
Superphylum:	Ecdysozoa
(unranked):	Panarthropoda
(unranked):	Tactopoda
Phylum:	Arthropoda Gravenhorst, 1843[1]
Subgroups

Subphyla, unplaced genera, and classes

Arthropods (/ˈɑːrθrəpɒd/, from Ancient Greek ἄρθρον (arthron) 'joint', and πούς (pous) 'foot' (gen. ποδός)) are invertebrate animals in the phylum Arthropoda. They possess an exoskeleton with a cuticle made of chitin, often mineralised with calcium carbonate, a segmented body, and paired jointed appendages. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. They are an extremely diverse group, with up to 10 million species. 

https://en.wikipedia.org/wiki/Arthropod

Chloropidae
Chlorops sp.
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Diptera
(unranked):	Eremoneura
(unranked):	Cyclorrhapha
Section:	Schizophora
Subsection:	Acalyptratae
Superfamily:	Carnoidea
Family:	Chloropidae Rondani, 1856
Subfamilies
Chloropinae Oscinellinae Rhodesiellinae Siphonellopsinae
Diversity
More than 160 genera
Synonyms
Mindidae

The Chloropidae are a family of flies commonly known as frit flies or grass flies.^[1] About 2000 described species are in over 160 genera distributed worldwide. These are usually very small flies, yellow or black and appearing shiny due to the virtual absence of any hairs. The majority of the larvae are phytophagous, mainly on grasses, and can be major pests of cereals. However, parasitic and predatory species are known. A few species are kleptoparasites. Some species in the genera Hippelates and Siphunculina (S. funicola being quite well known in Asia) are called eye gnats or eye flies for their habit of being attracted to eyes. They feed on lachrymal secretions and other body fluids of various animals, including humans, and are of medical significance.^[2][3]

There are scant records of chloropids from amber deposits, mostly from the Eocene and Oligocene periods although some material may suggest the family dates back to the Cretaceous or earlier. 

https://en.wikipedia.org/wiki/Chloropidae

Siphunculina
Siphunculina funicola
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Diptera
Family:	Chloropidae
Subfamily:	Oscinellinae
Genus:	Siphunculina Rondani, 1856
Species
see text

Siphunculina is a genus of small flies known as tropical eye flies. They are known for their habit of visiting the eyes of humans and other vertebrates to feed on fluids and in doing so cause annoyance, spread bacterial or viral diseases or cause injury to the eye.^[1][2] They have a habit of resting in large numbers on suspended strings, ropes and cobwebs.^[3]

Several species are known from the Old World, including Asia, Europe and Africa.^{[4][5][6] [7][8][9]} 

https://en.wikipedia.org/wiki/Siphunculina

 

Schizophora Temporal range: Paleogene–Recent PreꞒ Ꞓ O S D C P T J K Pg N
Marsh fly (Sciomyzidae)
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Diptera
(unranked):	Cyclorrhapha
Section:	Schizophora Becher, 1882
Subsections
Acalyptratae Calyptratae

The Schizophora are a section of true flies containing 78 families, which are collectively referred to as muscoids, although technically the term "muscoid" should be limited to flies in the superfamily Muscoidea; this is an example of informal, historical usage persisting in the vernacular. The section is divided into two subsections, the Acalyptratae and Calyptratae, which are commonly referred to as acalyptrate muscoids and calyptrate muscoids, respectively. 

https://en.wikipedia.org/wiki/Schizophora

The defining feature of the Schizophora is the presence of a special structure used to help the emerging adult fly break free of the puparium; this structure is an inflatable membranous sac called the ptilinum that protrudes from the face, above the antennae. The inflation of the ptilinum (using fluid hemolymph rather than air) creates pressure along the line of weakness in the puparium, which then bursts open along the seam to allow the adult to escape. When the adult emerges, the fluid is withdrawn, the ptilinum collapses, and the membrane retracts entirely back inside the head. The large, inverted, "U"-shaped suture in the face through which it came, however, is still quite visible, and the name "Schizophora" ("split-bearers") is derived from this ptilinal or frontal suture. The term was first used by Eduard Becher. 

https://en.wikipedia.org/wiki/Schizophora

Muscoidea
Anthomyia pluvialis
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Diptera
(unranked):	Eremoneura
(unranked):	Cyclorrhapha
Section:	Schizophora
Subsection:	Calyptratae
Superfamily:	Muscoidea
Families
Anthomyiidae — cabbage flies Fanniidae — little house flies Muscidae — house flies Scathophagidae — dung flies

Muscoidea is a superfamily of flies in the subsection Calyptratae. Muscoidea, with approximately 7000 described species, is nearly 5% of the known species level diversity of the Diptera, the true flies. Most muscoid flies are saprophagous, coprophagous or necrophagous as larvae, but some species are parasitic, predatory, or phytophagous.^[1] In September 2008, a study was done on the superfamily using both nucleic and mitochondrial DNA and the conclusion suggested that Muscoidea may actually be paraphyletic.^[2] 

https://en.wikipedia.org/wiki/Muscoidea

For the entertainment company, see Chorion (company).

Chorion
Diagram showing the chorion of a chicken egg
Human fetus, enclosed in the amnion
Details
Identifiers
Latin	chorion
MeSH	D002823
TE	E5.11.3.1.1.0.3
Anatomical terminology [edit on Wikidata]

The chorion is the outermost fetal membrane around the embryo in mammals, birds and reptiles (amniotes). It develops from an outer fold on the surface of the yolk sac, which lies outside the zona pellucida (in mammals), known as the vitelline membrane in other animals. In insects it is developed by the follicle cells while the egg is in the ovary.^[1]

^{https://en.wikipedia.org/wiki/Chorion}

 

Monotremes[1] Temporal range: Early Cretaceous (Barremian) – Present PreꞒ Ꞓ O S D C P T J K Pg N
Four of the five extant monotreme species: platypus (top-left), short-beaked echidna (top-right), western long-beaked echidna (bottom-left), and replica eastern long-beaked echidna (bottom-right)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Monotremata C.L. Bonaparte, 1837[2]
Subgroups
†Kryoryctes? †Patagorhynchus †Stirtodon †Sundrius? †Steropodontidae †Teinolophidae †Kollikodontidae Ornithorhynchidae Tachyglossidae

Monotremes (/ˈmɒnətriːmz/) are mammals of the order Monotremata. They are one of the three groups of living mammals, along with placentals (Eutheria), and marsupials (Metatheria). Monotremes are typified by structural differences in their brains, jaws, digestive tract, reproductive tract, and other body parts, compared to the more common mammalian types. In addition, they lay eggs rather than bearing live young, but, like all mammals, the female monotremes nurse their young with milk.

Monotremes have been considered members of Australosphenida, a clade that contains extinct mammals from the Jurassic and Cretaceous of Madagascar, South America, and Australia, though this is disputed.

The only surviving examples of monotremes are all indigenous to Australia and New Guinea, although they were also present in the Late Cretaceous and Paleocene of southern South America, indicating that they were also present in Antarctica, though remains have not been found there. The extant monotreme species are the platypus and four species of echidnas. There is currently some debate regarding monotreme taxonomy.

The name monotreme derives from the Greek words μονός (monós 'single') and τρῆμα (trêma 'hole'), referring to the cloaca. 

https://en.wikipedia.org/wiki/Monotreme

Patagorhynchus Temporal range: Early Maastrichtian
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Monotremata
Genus:	†Patagorhynchus
Species:	†P. pascuali
Binomial name
Patagorhynchus pascuali

Patagorhynchus is a genus of prehistoric monotreme mammal from the Late Cretaceous Early Maastrichtian age of Santa Cruz province, Argentina. It is known from a single species: Patagorhynchus pascuali.^[1] The holotype, MPM-PV-23087, consists of a lower right molar attached to a fragment of dentary. It was collected in the Chorillo Formation of Rio Gallegos, Santa Cruz, Argentina in 2022 and is housed in the Museo Padre Molina.^[1] 

https://en.wikipedia.org/wiki/Patagorhynchus

Maastrichtian
72.1 ± 0.2 – 66.0 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Opening of the western Indian Ocean in the Maastrichtian
Chronology
−140 — – −130 — – −120 — – −110 — – −100 — – −90 — – −80 — – −70 — – M e s o z o i c C Z J C r e t a c e o u s P g L J E a r l y L a t e P C Tithonian Berriasian Valanginian Hauterivian Barremian Aptian Albian Cenoman. Turonian Coniacian Santonian Campanian Maastricht. Danian       ← K-Pg mass extinction Subdivision of the Cretaceous according to the ICS, as of 2022.[1] Vertical axis scale: millions of years ago.
Etymology
Name formality	Formal
Usage information
Celestial body	Earth
Regional usage	Global (ICS)
Time scale(s) used	ICS Time Scale
Definition
Chronological unit	Age
Stratigraphic unit	Stage
Time span formality	Formal
Lower boundary definition	Mean of 12 biostratigraphic criteria
Lower boundary GSSP	Grande Carrière quarry, Landes, France 43.6795°N 1.1133°W
Lower GSSP ratified	February 2001[2]
Upper boundary definition	Iridium enriched layer associated with a major meteorite impact and subsequent K-Pg extinction event.
Upper boundary GSSP	El Kef Section, El Kef, Tunisia 36.1537°N 8.6486°E
Upper GSSP ratified	1991

The Maastrichtian ( /mɑːˈstrɪktiən/) is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from 72.1 to 66 million years ago. The Maastrichtian was preceded by the Campanian and succeeded by the Danian (part of the Paleogene and Paleocene).^[3]

The Cretaceous–Paleogene extinction event (formerly known as the Cretaceous–Tertiary extinction event)^[a] occurred at the end of this age.^[3] In this mass extinction, many commonly recognized groups such as non-avian dinosaurs, plesiosaurs and mosasaurs, as well as many other lesser-known groups, died out. The cause of the extinction is most commonly linked to an asteroid about 10 to 15 kilometres (6.2 to 9.3 mi) wide^[4][5] colliding with Earth, ending the Cretaceous. 

https://en.wikipedia.org/wiki/Maastrichtian

 

Series are subdivisions of rock layers based on the age of the rock and formally defined by international conventions of the geological timescale. A series is therefore a sequence of strata defining a chronostratigraphic unit. Series are subdivisions of systems and are themselves divided into stages.

Series is a term defining a unit of rock layers formed during a certain interval of time (a chronostratigraphic unit); it is equivalent (but not synonymous) to the term geological epoch (see epoch criteria) which defines the interval of time itself, although the two words are sometimes confused in informal literature. 

https://en.wikipedia.org/wiki/Series_(stratigraphy)

Units in geochronology and stratigraphy^[1]

Segments of rock (strata) in chronostratigraphy	Time spans in geochronology	Notes to geochronological units
Eonothem	Eon	4 total, half a billion years or more
Erathem	Era	10 defined, several hundred million years
System	Period	22 defined, tens to ~one hundred million years
Series	Epoch	34 defined, tens of millions of years
Stage	Age	99 defined, millions of years
Chronozone	Chron	subdivision of an age, not used by the ICS timescale

https://en.wikipedia.org/wiki/Series_(stratigraphy)

 

From Wikipedia, the free encyclopedia

Chronostratigraphy is the branch of stratigraphy that studies the ages of rock strata in relation to time.

The ultimate aim of chronostratigraphy is to arrange the sequence of deposition and the time of deposition of all rocks within a geological region, and eventually, the entire geologic record of the Earth.

The standard stratigraphic nomenclature is a chronostratigraphic system based on palaeontological intervals of time defined by recognised fossil assemblages (biostratigraphy). The aim of chronostratigraphy is to give a meaningful age date to these fossil assemblage intervals and interfaces.^[1]

Methodology

Chronostratigraphy relies heavily upon isotope geology and geochronology to derive hard dating of known and well defined rock units which contain the specific fossil assemblages defined by the stratigraphic system. In practice, as it is very difficult to isotopically date most fossils and sedimentary rocks directly, inferences must be made in order to arrive at an age date which reflects the beginning of the interval.

The methodology used is derived from the law of superposition and the principles of cross-cutting relationships. 

https://en.wikipedia.org/wiki/Chronostratigraphy

The methodology used is derived from the law of superposition and the principles of cross-cutting relationships.

Because igneous rocks occur at specific intervals in time and are essentially instantaneous on a geologic time scale, and because they contain mineral assemblages which may be dated more accurately and precisely by isotopic methods, the construction of a chronostratigraphic column relies heavily upon intrusive and extrusive igneous rocks.

Metamorphism, often associated with faulting, may also be used to bracket depositional intervals in a chronostratigraphic column. Metamorphic rocks can occasionally be dated, and this may give some limits to the age at which a bed could have been laid down. For example, if a bed containing graptolites overlies crystalline basement at some point, dating the crystalline basement will give a maximum age of that fossil assemblage.

This process requires a considerable degree of effort and checking of field relationships and age dates. For instance, there may be many millions of years between a bed being laid down and an intrusive rock cutting it; the estimate of age must necessarily be between the oldest cross-cutting intrusive rock in the fossil assemblage and the youngest rock upon which the fossil assemblage rests. 

https://en.wikipedia.org/wiki/Chronostratigraphy

Units

Chronostratigraphic units, with examples:^[2]

• eonothem – Phanerozoic
• erathem – Paleozoic
• system – Ordovician
• series – Upper Ordovician
• stage – Ashgill

Differences from geochronology

It is important not to confuse geochronologic and chronostratigraphic units.^[3][4] Chronostratigraphic units are geological material, so it is correct to say that fossils of the species Tyrannosaurus rex have been found in the Upper Cretaceous Series.^[5] Geochronological units are periods of time and take the same name as standard stratigraphic units but replacing the terms upper/lower with late/early. Thus it is also correct to say that Tyrannosaurus rex lived during the Late Cretaceous Epoch.^[6]

Chronostratigraphy is an important branch of stratigraphy because the age correlations derived are crucial in drawing accurate cross sections of the spatial organization of rocks and in preparing accurate paleogeographic reconstructions.

See also

• Biostratigraphy
• Chronozone
• Geochronology
• Geologic record
• Geologic time scale
• List of geochronologic names
• Tectonostratigraphy

https://en.wikipedia.org/wiki/Chronostratigraphy

 

Category:Geochronological dating methods

• Category
• Talk

• Read
• Edit
• View history

Tools

• 
  
• 
  
• 
  
• 
  
• 
  
• 
  
• 
  

• 
  
• 
  

Help

From Wikipedia, the free encyclopedia

For more information, see Geochronometry.

• Geology portal

Subcategories

This category has the following 4 subcategories, out of 4 total.

I

• 
  

• Incremental dating‎ (14 P)

L

• 
  

• Lithostratigraphy‎ (1 C, 5 P)

P

• 
  

• Paleomagnetism‎ (1 C, 10 P)

R

• 
  

• Radiometric dating‎ (2 C, 29 P)

Pages in category "Geochronological dating methods"

The following 17 pages are in this category, out of 17 total. This list may not reflect recent changes.

A

• Amino acid dating
• Astrochronology

B

• Biochronology

C

• Chronostratigraphy
• Comminution dating

D

• Detrital zircon geochronology

E

• Electron spin resonance dating

G

• Geochronometry

I

• Isotope geochemistry

L

• Lithostratigraphy
• Luminescence dating

M

• Monazite geochronology

O

• Oxygen isotope ratio cycle

P

• Paleomagnetism

R

• Reduced chi-squared statistic

S

• Sensitive high-resolution ion microprobe
• Surface exposure dating

Categories:

• Geochronology
• Dating methods

 https://en.wikipedia.org/wiki/Category:Geochronological_dating_methods

From Wikipedia, the free encyclopedia

Commissural fiber
Coronal cross-section of brain showing the corpus callosum at top and the anterior commissure below
Details
Identifiers
Latin	fibra commissuralis, fibrae commissurales telencephali
NeuroNames	1220
TA98	A14.1.00.017 A14.1.09.569
TA2	5603
FMA	75249
Anatomical terms of neuroanatomy [edit on Wikidata]

The commissural fibers or transverse fibers are axons that connect the two hemispheres of the brain. In contrast to commissural fibers, association fibers connect regions within the same hemisphere of the brain, and projection fibers connect each region to other parts of the brain or to the spinal cord.^[1]

 https://en.wikipedia.org/wiki/Commissural_fiber

General characteristics

Like other mammals, monotremes are endothermic with a high metabolic rate (though not as high as other mammals; see below); have hair on their bodies; produce milk through mammary glands to feed their young; have a single bone in their lower jaw; and have three middle-ear bones.

In common with reptiles and marsupials, monotremes lack the connective structure (corpus callosum) which in placental mammals is the primary communication route between the right and left brain hemispheres.^[3] The anterior commissure does provide an alternate communication route between the two hemispheres, though, and in monotremes and marsupials it carries all the commissural fibers arising from the neocortex, whereas in placental mammals the anterior commissure carries only some of these fibers.^[4]

Platypus

Long-beaked echidna

Diagram of a monotreme egg. (1) Shell; (2) Yolk; (3) Yolk Sac; (4) Allantois; (5) Embryo; (6) Amniotic Fluid; (7) Amniotic Membrane; and (8) Membrane

Extant monotremes lack teeth as adults. Fossil forms and modern platypus young have a "tribosphenic" form of molars (with the occlusal surface formed by three cusps arranged in a triangle), which is one of the hallmarks of extant mammals. Some recent work suggests that monotremes acquired this form of molar independently of placental mammals and marsupials,^[5] although this hypothesis remains disputed.^[6] Tooth loss in modern monotremes might be related to their development of electrolocation.^[7]

Monotreme jaws are constructed somewhat differently from those of other mammals, and the jaw opening muscle is different. As in all true mammals, the tiny bones that conduct sound to the inner ear are fully incorporated into the skull, rather than lying in the jaw as in non-mammal cynodonts and other premammalian synapsids; this feature, too, is now claimed to have evolved independently in monotremes and therians,^[8] although, as with the analogous evolution of the tribosphenic molar, this hypothesis is disputed.^[9][10] Nonetheless, findings on the extinct species Teinolophos confirm that suspended ear bones evolved independently among monotremes and therians.^[11] The external opening of the ear still lies at the base of the jaw.

The sequencing of the platypus genome has also provided insight into the evolution of a number of monotreme traits, such as venom and electroreception, as well as showing some new unique features, such as monotremes possessing 5 pairs of sex chromosomes and that one of the X chromosomes resembles the Z chromosome of birds,^[12] suggesting that the two sex chromosomes of marsupial and placental mammals evolved after the split from the monotreme lineage.^[13] Additional reconstruction through shared genes in sex chromosomes supports this hypothesis of independent evolution.^[14] This feature, along with some other genetic similarities with birds, such as shared genes related to egg-laying, is thought to provide some insight into the most recent common ancestor of the synapsid lineage leading to mammals and the sauropsid lineage leading to birds and modern reptiles, which are believed to have split about 315 million years ago during the Carboniferous.^[15][16] The presence of vitellogenin genes (a protein necessary for egg shell formation) is shared with birds; the presence of this symplesiomorphy suggests that the common ancestor of monotremes, marsupials, and placental mammals was oviparous, and that this trait was retained in monotremes but lost in all other extant mammal groups. DNA analyses suggest that although this trait is shared and is synapomorphic with birds, platypuses are still mammals and that the common ancestor of extant mammals lactated.^[17]

The monotremes also have extra bones in the shoulder girdle, including an interclavicle and coracoid, which are not found in other mammals. Monotremes retain a reptile-like gait, with legs on the sides of, rather than underneath, their bodies. The monotreme leg bears a spur in the ankle region; the spur is not functional in echidnas, but contains a powerful venom in the male platypus. This venom is derived from β-defensins, proteins that are present in mammals that create holes in viral and bacterial pathogens. Some reptile venom is also composed of different types of β-defensins, another trait shared with reptiles.^[15] It is thought to be an ancient mammalian characteristic, as many non-monotreme archaic mammal groups also possess venomous spurs.^[18]

Reproductive system

This section may be expanded with text translated from the corresponding article in French. (August 2014) Click [show] for important translation instructions.

Further information: Echidna § Reproduction, and Platypus § Reproduction

The key anatomical difference between monotremes and other mammals gives them their name; monotreme means “single opening” in Greek, referring to the single duct (the cloaca) for their urinary, defecatory, and reproductive systems. Like reptiles, monotremes have a single cloaca. Marsupials have a separate genital tract, whereas most placental mammalian females have separate openings for reproduction (the vagina), urination (the urethra), and defecation (the anus). In monotremes, only semen passes through the penis while urine is excreted through the male's cloaca.^[19] The monotreme penis is similar to that of turtles and is covered by a preputial sac.^[20][21]

Monotreme eggs are retained for some time within the mother and receive nutrients directly from her, generally hatching within 10 days after being laid — much shorter than the incubation period of sauropsid eggs.^[22][23] Much like newborn marsupials (and perhaps all non-placental mammals^[24]), newborn monotremes, called "puggles,"^[25] are larval- and fetus-like and have relatively well-developed forelimbs that enable them to crawl around. In fact, because monotremes lack nipples, puggles crawl about more frequently than marsupial joeys in search of milk, this difference raising questions about the supposed developmental restrictions on marsupial forelimbs.^{[clarification needed][26]}

Rather than through nipples, monotremes lactate from their mammary glands via openings in their skin. All five extant species show prolonged parental care of their young, with low rates of reproduction and relatively long life-spans.

Monotremes are also noteworthy in their zygotic development: Most mammalian zygotes go through holoblastic cleavage, where the ovum splits into multiple, divisible daughter cells. Contrastingly, monotreme zygotes, like those of birds and reptiles, undergo meroblastic (partial) division. This means the cells at the yolk's edge have cytoplasm continuous with that of the egg, allowing the yolk and embryo to exchange waste and nutrients with the surrounding cytoplasm.^[15]

Physiology

Monotreme female reproductive organs

Male platypus reproductive system. 1. Testes, 2. Epididymis, 3. Bladder, 4. Rectum, 5. Ureter, 6. Vas Deferens, 7. Genito-urinary sinus, 8. Penis enclosed in a fibrous sheath, 9. Cloaca, 10. Opening in the ventral wall of the cloaca for the penis.

Monotremes' metabolic rate is remarkably low by mammalian standards. The platypus has an average body temperature of about 31 °C (88 °F) rather than the averages of 35 °C (95 °F) for marsupials and 37 °C (99 °F) for placental mammals.^[27][28] Research suggests this has been a gradual adaptation to the harsh, marginal environmental niches in which the few extant monotreme species have managed to survive, rather than a general characteristic of extinct monotremes.^[29][30]

Monotremes may have less developed thermoregulation than other mammals, but recent research shows that they easily maintain a constant body temperature in a variety of circumstances, such as the platypus in icy mountain streams. Early researchers were misled by two factors: firstly, monotremes maintain a lower average temperature than most mammals; secondly, the short-beaked echidna, much easier to study than the reclusive platypus, maintains normal temperature only when active; during cold weather, it conserves energy by "switching off" its temperature regulation. Understanding of this mechanism came when reduced thermal regulation was observed in the hyraxes, which are placental mammals.

The echidna was originally thought to experience no rapid eye movement sleep.^[31] However, a more recent study showed that REM sleep accounted for about 15% of sleep time observed on subjects at an environmental temperature of 25 °C (77 °F). Surveying a range of environmental temperatures, the study observed very little REM at reduced temperatures of 15 °C (59 °F) and 20 °C (68 °F), and also a substantial reduction at the elevated temperature of 28 °C (82 °F).^[32]

Monotreme milk contains a highly expressed antibacterial protein not found in other mammals, perhaps to compensate for the more septic manner of milk intake associated with the absence of nipples.^[33]

During the course of evolution the monotremes have lost the gastric glands normally found in mammalian stomachs as an adaptation to their diet.^[34] Monotremes synthesize L-ascorbic acid only in the kidneys.^[35]

Both the platypus and echidna species have spurs on their hind limbs. The echidna spurs are vestigial and have no known function, while the platypus spurs contain venom.^[36] Molecular data show that the main component of platypus venom emerged before the divergence of platypus and echidnas, suggesting that the most recent common ancestor of these taxa was also possibly a venomous monotreme.^[37]

Taxonomy

The traditional "theria hypothesis" states that the divergence of the monotreme lineage from the Metatheria (marsupial) and Eutheria (placental mammal) lineages happened prior to the divergence between marsupials and placental mammals, and this explains why monotremes retain a number of primitive traits presumed to have been present in the synapsid ancestors of later mammals, such as egg-laying.^[38][39][40] Most morphological evidence supports the theria hypothesis, but one possible exception is a similar pattern of tooth replacement seen in monotremes and marsupials, which originally provided the basis for the competing "Marsupionta" hypothesis in which the divergence between monotremes and marsupials happened later than the divergence between these lineages and the placental mammals. Van Rheede (2005) concluded that the genetic evidence favors the theria hypothesis,^[41] and this hypothesis continues to be the more widely accepted one.^[42]

Monotremes are conventionally treated as comprising a single order Monotremata. The entire grouping is also traditionally placed into a subclass Prototheria, which was extended to include several fossil orders, but these are no longer seen as constituting a group allied to monotreme ancestry. A controversial hypothesis now relates the monotremes to a different assemblage of fossil mammals in a clade termed Australosphenida, a group of mammals from the Jurassic and Cretaceous of Madagascar, South America and Australia, that share tribosphenic molars.^[5][43] However in a 2022 review of monotreme evolution, it was noted that Teinolophos, the oldest (Barremian ~ 125 million years ago) and the most primitive monotreme differed substantially from non-monotreme australosphenidans in having five molars as opposed to the three present in non-monotreme australosphenidians. Aptian and Cenomanian monotremes of the family Kollikodontidae (113-96.6 ma) have four molars. This suggests that the monotremes are likely to be unrelated to the australosphenidan tribosphenids.^[44]

The time when the monotreme line diverged from other mammalian lines is uncertain, but one survey of genetic studies gives an estimate of about 220 million years ago,^[45] while others have posited younger estimates of 163 to 186 million years ago. Teinolophos like modern monotremes displays adaptations to elongation and increased sensory perception in the jaws, related to mechanoreception or electroreception.^[44]

A fossil jaw fragment attributed to a platypus from Cenomanian deposits (100-96.6 ma) from the Griman Creek Formation in Lightning Ridge, New South Wales, is the oldest platypus-like fossil.^[44] The durophagous Kollikodon, the pseudotribosphenic Steropodon, and Stirtodon occur in the same Cenomanian deposits. Oligo-Miocene fossils of the toothed platypus Obdurodon have also been recovered from Australia, and fossils of a 63 million-year old platypus occur in southern Argentina (Monotrematum), see fossil monotremes below. The platypus genus Ornithorhynchus in known from Pliocene deposits, and the oldest fossil tachyglossids are Pleistocene (1.7 ma) in age.^[44]

Molecular clock and fossil dating give a wide range of dates for the split between echidnas and platypuses, with one survey putting the split at 19–48 million years ago,^[46] but another putting it at 17–89 million years ago.^[47] It has been suggested that both the short-beaked and long-beaked echidna species are derived from a platypus-like ancestor.^[44]

The precise relationships among extinct groups of mammals and modern groups such as monotremes are uncertain, but cladistic analyses usually put the last common ancestor (LCA) of placentals and monotremes close to the LCA of placentals and multituberculates, whereas some suggest that the LCA of placentals and multituberculates was more recent than the LCA of placentals and monotremes.^[48][49]

0:44

An echidna excavating a defensive burrow on French Island

• ORDER MONOTREMATA
  • Family Ornithorhynchidae: platypus
    • Genus Ornithorhynchus
      • Platypus, O. anatinus
  • Family Tachyglossidae: echidnas
    • Genus Tachyglossus
      • Short-beaked echidna, T. aculeatus
        • T. a. aculeatus (Common short-beaked echidna)
        • T. a. acanthion (Northern short-beaked echidna)
        • T. a. lawesii (New Guinea short-beaked echidna)
        • T. a. multiaculeatus (Kangaroo Island short-beaked echidna)
        • T. a. setosus (Tasmanian short-beaked echidna)
    • Genus Zaglossus
      • Sir David's long-beaked echidna, Z. attenboroughi
      • Eastern long-beaked echidna, Z. bartoni
        • Z. b. bartoni
        • Z. b. clunius
        • Z. b. diamondi
        • Z. b. smeenki
      • Western long-beaked echidna, Z. bruijni

Fossil monotremes

See also: Evolution of mammals

A model of the extinct platypod Steropodon at the Australian Museum.

The first Mesozoic monotreme to be discovered was the Cenomanian (100-96.6 ma) Steropodon galmani from Lightning Ridge, New South Wales.^[50] Biochemical and anatomical evidence suggests that the monotremes diverged from the mammalian lineage before the marsupials and placental mammals arose. The only Mesozoic monotremes are Teinolophos (Barremian, 126 ma), Sundrius and Kryoryctes (Albian, 113-108 ma), Steropodon, Stirtodon, Kollikodon, and an unnamed ornithorhynchid (all Cenomanian) from Australian deposits in the Cretaceous, indicating that monotremes were diversifiying by the early Late Cretaceous.^[51] Monotremes have been found in the latest Cretaceous and Paleocene of southern South America, so one hypothesis is that monotremes arose in Australia in the Late Jurassic or Early Cretaceous, and that some migrated across Antarctica to South America, both of which were still united with Australia at that time.^[52][53]

Fossil species

A 100 million-year-old Steropodon jaw on display at the American Museum of Natural History, New York City, USA

1:16

Platypuses swimming at Sydney Aquarium

Excepting Ornithorhynchus anatinus, all the animals listed in this section are known only from fossils.

• Family Incertae sedis
  • Genus Kryoryctes
    • Species Kryoryctes cadburyi
  • Genus Patagorhynchus
    • Species Patagorhynchus pascuali - Maastrichtian, earliest known South American monotreme^[53]
• Family Steropodontidae – paraphyletic assemblage
  • Genus Steropodon
    • Species Steropodon galmani
  • Genus Teinolophos
    • Species Teinolophos trusleri – 123 million years old, oldest monotreme specimen
• Family Ornithorhynchidae
  • Genus Ornithorhynchus – oldest Ornithorhynchus specimen 9 million years old
    • Species Ornithorhynchus anatinus (platypus) – oldest specimen 10,000 years old
  • Genus Obdurodon – includes a number of Miocene (5–24 million years ago) Riversleigh platypuses)
    • Species Obdurodon dicksoni
    • Species Obdurodon insignis
    • Species Obdurodon tharalkooschild – Middle Miocene and Upper Miocene (15–5 mya)
  • Genus Monotrematum
    • Species Monotrematum sudamericanum – 61 million years old, southern South America
• Family Tachyglossidae
  • Genus Zaglossus – Upper Pleistocene (0.1–1.8 million years ago)
    • Species Zaglossus robustus
  • Genus Murrayglossus
    • Species Murrayglossus hacketti
  • Genus Megalibgwilia
    • Species Megalibgwilia ramsayi – Late Pleistocene
    • Species Megalibgwilia robusta – Miocene

References

1. 
   

Groves, C. P. (2005). Wilson, D. E.; Reeder, D. M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. pp. 1–2. ISBN 0-801-88221-4. OCLC 62265494.

Bonaparte, C.L. (1837). "A New Systematic Arrangement of Vertebrated Animals". Transactions of the Linnean Society of London. 18 (3): 258. doi:10.1111/j.1095-8339.1838.tb00177.x.

"Order Monotremata". Animal Bytes. Archived from the original on 23 December 2010. Retrieved 6 September 2009.

Butler, Ann B.; Hodos, William (2005). Comparative Vertebrate Neuroanatomy: Evolution and Adaptation. Wiley. p. 361. ISBN 978-0-471-73383-6.

Luo, Z.-X.; Cifelli, R.L.; Kielan-Jaworowska, Z. (2001). "Dual origin of tribosphenic mammals". Nature. 409 (6816): 53–57. Bibcode:2001Natur.409...53L. doi:10.1038/35051023. PMID 11343108. S2CID 4342585.

Weil, A. (4 January 2001). "Mammalian evolution: Relationships to chew over". Nature. 409 (6816): 28–31. Bibcode:2001Natur.409...28W. doi:10.1038/35051199. PMID 11343097. S2CID 37912232.

Masakazu Asahara; Masahiro Koizumi; Macrini, Thomas E.; Hand, Suzanne J.; Archer, Michael (2016). "Comparative cranial morphology in living and extinct platypuses: Feeding behavior, electroreception, and loss of teeth". Science Advances. 2 (10): e1601329. Bibcode:2016SciA....2E1329A. doi:10.1126/sciadv.1601329. PMC 5061491. PMID 27757425.

Rich, T.H.; Hopson, J.A.; Musser, A.M.; Flannery, T.F.; Vickers-Rich, P. (2005). "Independent origins of middle ear bones in monotremes and therians (I)". Science. 307 (5711): 910–914. Bibcode:2005Sci...307..910R. doi:10.1126/science.1105717. PMID 15705848. S2CID 3048437.

Bever, G.S.; Rowe, T.; Ekdale, E.G.; MacRini, T.E.; Colbert, M.W.; Balanoff, A.M. (2005). "Comment on "Independent Origins of Middle Ear Bones in Monotremes and Therians" (I)". Science. 309 (5740): 1492a. doi:10.1126/science.1112248. PMID 16141050.

Rougier, G.W. (2005). "Comment on "Independent Origins of Middle Ear Bones in Monotremes and Therians" (II)". Science. 309 (5740): 1492b. doi:10.1126/science.1111294. PMID 16141051.

Rich, Thomas H.; Hopson, James A.; Gill, Pamela G.; Trusler, Peter; Rogers-Davidson, Sally; Morton, Steve; et al. (2016). "The mandible and dentition of the Early Cretaceous monotreme Teinolophos trusleri". Alcheringa: An Australasian Journal of Palaeontology. 40 (4): 475–501. doi:10.1080/03115518.2016.1180034. S2CID 89034974.

"Platypus genome explains animal's peculiar features; holds clues to evolution of mammals". Sciencedaily.com. 7 May 2008. Retrieved 9 June 2011.

Veyrunes; et al. (June 2008). "Bird-like sex chromosomes of platypus imply recent origin of mammal sex chromosomes". Genome Res. 18 (6): 965–973. doi:10.1101/gr.7101908. PMC 2413164. PMID 18463302.

Cortez, Diego; Marin, Ray; Toledo-Flores, Deborah; Froidevaux, Laure; Liechti, Angélica; Waters, Paul D.; Grützner, Frank; Kaessmann, Henrik (24 April 2014). "Origins and functional evolution of Y chromosomes across mammals". Nature. 508 (7497): 488–493. Bibcode:2014Natur.508..488C. doi:10.1038/nature13151. PMID 24759410. S2CID 4462870.

Myers, PZ (2008). "Interpreting Shared Characteristics: The Platypus Genome". Nature Education. 1 (1): 46.

Warren, W. C.; Hillier, L. W.; Marshall Graves, J. A.; Birney, E.; Ponting, C. P.; Grützner, F.; et al. (2008). "Genome analysis of the platypus reveals unique signatures of evolution". Nature. 453 (7192): 175–183. Bibcode:2008Natur.453..175W. doi:10.1038/nature06936. PMC 2803040. PMID 18464734.

Brawand D, Wahli W, Kaessmann H (2008). "Loss of egg yolk genes in mammals and the origin of lactation and placentation". PLOS Biol. 6 (3): e63. doi:10.1371/journal.pbio.0060063. PMC 2267819. PMID 18351802.

Hurum, Jørn H.; Zhe-Xi Luo; Kielan-Jaworowska, Zofia (2006). "Were mammals originally venomous?". Acta Palaeontologica Polonica. 51 (1): 1–11.

Griffiths, Mervyn (2 December 2012). The Biology of the Monotremes. Elsevier Science. ISBN 978-0-323-15331-7.

Grützner, F.; Nixon, B.; Jones, R.C. (2008). "Reproductive biology in egg-laying mammals". Sexual Development. 2 (3): 115–127. doi:10.1159/000143429. PMID 18769071. S2CID 536033.

Lombardi, Julian (6 December 2012). Comparative Vertebrate Reproduction. Springer Science & Business Media. ISBN 978-1-4615-4937-6.

Cromer, Erica (14 April 2004). Monotreme Reproductive Biology and Behavior (Report). Iowa State University.^{[full citation needed]}

"Short-beaked echidna (Tachyglossus aculeatus)". Arkive.org. Archived from the original on 13 August 2009. Retrieved 5 July 2016.

Power, Michael L.; Schulkin, Jay (2012). The Evolution of the Human Placenta. Johns Hopkins University Press. pp. 68ff. ISBN 978-1-4214-0870-5.

Ashwell, K. W.; Shulruf, B.; Gurovich, Y. (2019). "Quantitative analysis of the timing of development of the cerebellum and precerebellar nuclei in monotremes, metatherians, rodents, and humans". The Anatomical Record. 303 (7): 1998–2013. doi:10.1002/ar.24295. PMID 31633884. S2CID 204815010.

Schneider, Nanette Y. (2011). "The development of the olfactory organs in newly hatched monotremes and neonate marsupials". J. Anat. 219 (2): 229–42. doi:10.1111/j.1469-7580.2011.01393.x. PMC 3162242. PMID 21592102.

White (1999). "Thermal Biology of the Platypus". Davidson College. Archived from the original on 6 March 2012. Retrieved 14 September 2006.

"Control Systems Part 2" (PDF). Retrieved 6 July 2016.

Watson, J.M.; Graves, J.A.M. (1988). "Monotreme Cell-Cycles and the Evolution of Homeothermy". Australian Journal of Zoology. 36 (5): 573–584. doi:10.1071/ZO9880573.

Dawson, T.J.; Grant, T.R.; Fanning, D. (1979). "Standard Metabolism of Monotremes and the Evolution of Homeothermy". Australian Journal of Zoology. 27 (4): 511–515. doi:10.1071/ZO9790511.

Siegel, J.M.; Manger, P.R.; Nienhuis, R.; Fahringer, H.M.; Pettigrew, J.D. (1998). "Monotremes and the evolution of rapid eye movement sleep". Philosophical Transactions of the Royal Society B: Biological Sciences. 353 (1372): 1147–1157. doi:10.1098/rstb.1998.0272. PMC 1692309. PMID 9720111.

Nicol, S.C.; Andersen, N.A.; Phillips, N.H.; Berger, R.J. (2000). "The echidna manifests typical characteristics of rapid eye movement sleep". Neuroscience Letters. 283 (1): 49–52. doi:10.1016/S0304-3940(00)00922-8. PMID 10729631. S2CID 40439226.

Bisana, S.; Kumar, S.; Rismiller, P.; Nicol, S.C.; Lefèvre, C.; Nicholas, K.R.; Sharp, J.A. (9 January 2013). "Identification and functional characterization of a novel monotreme-specific antibacterial protein expressed during lactation". PLOS ONE. 8 (1): e53686. Bibcode:2013PLoSO...853686B. doi:10.1371/journal.pone.0053686. PMC 3541144. PMID 23326486.

Ordoñez, G.R.; Hillier, L.W.; et al. (May 2008). "Loss of genes implicated in gastric function during platypus evolution". Genome Biology. 9 (5): R81. doi:10.1186/gb-2008-9-5-r81. PMID 18482448. S2CID 2653017.

"Ascorbic acid biosynthesis in the mammalian kidney". ScienceScape.org. Archived from the original on 17 December 2014. Retrieved 14 November 2014.

Whittington, Camilla M.; Belov, Katherine (April 2014). "Tracing Monotreme Venom Evolution in the Genomics Era". Toxins. 6 (4): 1260–1273. doi:10.3390/toxins6041260. PMC 4014732. PMID 24699339.

Whittington, Camilla M.; Belov, Katherine (April 2014). "Tracing Monotreme Venom Evolution in the Genomics Era". Toxins. 6 (4): 1260–1273. doi:10.3390/toxins6041260. PMC 4014732. PMID 24699339.

Vaughan, Terry A.; Ryan, James M.; Czaplewski, Nicholas J. (2011). Mammalogy (5th ed.). Jones & Bartlett Learning. p. 80. ISBN 978-0-7637-6299-5.

"Introduction to the Monotremata". Ucmp.berkeley.edu. Retrieved 9 June 2011.

Jacks. "Lecture 3" (PDF). Moscow, ID: University of Idaho.

van Rheede, Teun (2005). "The platypus is in its place: Nuclear genes and indels confirm the sister group relation of monotremes and therians". Molecular Biology and Evolution. 23 (3): 587–597. doi:10.1093/molbev/msj064. PMID 16291999.

Janke, A.; Xu, X.; Arnason, U. (1997). "Monotremes". Proceedings of the National Academy of Sciences. 94 (4): 1276–1281. doi:10.1073/pnas.94.4.1276. PMC 19781. PMID 9037043. Retrieved 9 June 2011.

Luo, Z.-X.; Cifelli, R.L.; Kielan-Jaworowska, Z. (2002). "In quest for a phylogeny of Mesozoic mammals". Acta Palaeontologica Polonica. 47: 1–78.

Flannery, Timothy F.; Rich, Thomas H.; Vickers-Rich, Patricia; Ziegler, Tim; Veatch, E. Grace; Helgen, Kristofer M. (2022-01-02). "A review of monotreme (Monotremata) evolution". Alcheringa: An Australasian Journal of Palaeontology. 46 (1): 3–20. doi:10.1080/03115518.2022.2025900. ISSN 0311-5518. S2CID 247542433.

Madsen, Ole (2009). "chapter 68 – Mammals (Mamalia)". In Hedges, S. Blair; Kumar, Sudhir (eds.). The Timetree of Life. timetree.org. Oxford University Press. pp. 459–461. ISBN 978-0-19-953503-3.

Phillips, M.J.; Bennett, T.H.; Lee, M.S. (2009). "Molecules, morphology, and ecology indicate a recent, amphibious ancestry for echidnas". Proc. Natl. Acad. Sci. U.S.A. 106 (40): 17089–17094. Bibcode:2009PNAS..10617089P. doi:10.1073/pnas.0904649106. PMC 2761324. PMID 19805098.

Springer, Mark S.; Krajewski, Carey W. (2009). "chapter 69 – Monotremes (Prototheria)" (PDF). In Hedges, S. Blair; Kumar, Sudhir (eds.). The Timetree of Life. timetree.org. Oxford University Press. pp. 462–465.

Benton, Michael J. (2004). Vertebrate Palaeontology. Wiley. p. 300. ISBN 978-0-632-05637-8.

Carrano, Matthew T.; Blob, Richard W.; Gaudin, Timothy J.; Wible, John R. (2006). Amniote Paleobiology: Perspectives on the Evolution of Mammals, Birds, and Reptiles. University of Chicago Press. p. 358. ISBN 978-0-226-09478-6.

Ashwell, K., ed. (2013). Neurobiology of Monotremes. Melbourne: CSIRO Publishing. ISBN 9780643103115.

"Fossil Record of the Monotremata". Ucmp.berkeley.edu. Retrieved 9 June 2011.

Benton, Michael J. (1997). Vertebrate Palaeontology (2nd ed.). Wiley. pp. 303–304. ISBN 978-0-632-05614-9.

53. Chimento, N.R.; Agnolín, F.L.; et al. (16 February 2023). "First monotreme from the Late Cretaceous of South America". Communications Biology. 6: 146. doi:10.1038/s42003-023-04498-7.

Further reading

• Nowak, Ronald M. (1999). Walker's Mammals of the World (6th ed.). Baltimore, MD: Johns Hopkins University Press. ISBN 978-0-8018-5789-8. LCCN 98023686.

External links

Wikimedia Commons has media related to Monotremata.

The Wikibook Dichotomous Key has a page on the topic of: Monotremata

Wikispecies has information related to Monotremata.

• "Introduction to Monotremes". U.C. Museum of Peleontology. University of California – Berkeley.

v t e Extant Monotremata species by family
Kingdom Animalia Phylum Chordata Class Mammalia (unranked) Australosphenida
Tachyglossidae (Echidnas)	Tachyglossus Short-beaked echidna (T. aculeatus) Zaglossus (Long-beaked echidnas) Sir David's long-beaked echidna (Z. attenboroughi) Eastern long-beaked echidna (Z. bartoni) Western long-beaked echidna (Z. bruijni)
Ornithorhynchidae	Ornithorhynchus Platypus (O. anatinus)
Category

v t e Mammalia

v t e Extant mammal orders

v t e Eggs

Taxon identifiers	Wikidata: Q21790 Wikispecies: Monotremata ADW: Monotremata AFD: Monotremata BOLD: 358 CoL: 3L5 EoL: 1679 EPPO: 1MNTRO Fossilworks: 39737 GBIF: 791 iNaturalist: 43233 IRMNG: 10436 ITIS: 179915 MSW: 10300001 NCBI: 9255

Authority control: National	France BnF data Israel United States Japan Czech Republic

Categories:

• Monotremes
• Extant Late Triassic first appearances
• Taxa named by Charles Lucien Bonaparte

 

https://en.wikipedia.org/monotreme

 

The Cretaceous (IPA: /krɪˈteɪʃəs/ krih-TAY-shəs)^[2] is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin creta, "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation Kreide.

The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth by the end of the Cretaceous, coincident with the decline and extinction of previously widespread gymnosperm groups.

The Cretaceous (along with the Mesozoic) ended with the Cretaceous–Paleogene extinction event, a large mass extinction in which many groups, including non-avian dinosaurs, pterosaurs, and large marine reptiles, died out. The end of the Cretaceous is defined by the abrupt Cretaceous–Paleogene boundary (K–Pg boundary), a geologic signature associated with the mass extinction that lies between the Mesozoic and Cenozoic Eras. 

Cretaceous
~145.0 – 66.0 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Chronology
−140 — – −130 — – −120 — – −110 — – −100 — – −90 — – −80 — – −70 — – M e s o z o i c C Z Jurassic C r e t a c e o u s Paleogene E a r l y L a t e Berriasian Valanginian Hauterivian Barremian Aptian Albian Cenoman. Turonian Coniacian Santonian Campanian Maastricht.       ← K-Pg mass extinction Subdivision of the Cretaceous according to the ICS, as of 2022.[1] Vertical axis scale: millions of years ago.
Etymology
Name formality	Formal
Usage information
Celestial body	Earth
Regional usage	Global (ICS)
Time scale(s) used	ICS Time Scale
Definition
Chronological unit	Period
Stratigraphic unit	System
Time span formality	Formal
Lower boundary definition	Not formally defined
Lower boundary definition candidates	Magnetic—base of Chron M18r Base of Calpionellid zone B FAD of Ammonite Berriasella jacobi
Lower boundary GSSP candidate section(s)	None
Upper boundary definition	Iridium-enriched layer associated with a major meteorite impact and subsequent K-Pg extinction event
Upper boundary GSSP	El Kef Section, El Kef, Tunisia 36.1537°N 8.6486°E
Upper GSSP ratified	1991

 

https://en.wikipedia.org/wiki/Cretaceous 

From Wikipedia, the free encyclopedia

In geology, Neocomian was a name given to the lowest stage of the Cretaceous system. It is generally considered to encompass the interval now covered by the Berriasian, Valanginian and Hauterivian, from approximately 145 to 130 Ma.^[1] It was introduced by Jules Thurmann in 1835 on account of the development of these rocks at Neuchâtel (Neocomum), Switzerland. It has been employed in more than one sense. In the type area the rocks have been divided into two sub-stages, a lower, Valanginian (from Valengin, Pierre Jean Édouard Desor, 1854) and an upper, Hauterivian (from Hauterive, Eugène Renevier, 1874); there is also another local sub-stage, the infra-Valanginian or Berriasian (from Berrias, Henri Coquand, 1876). These three sub-stages constitute the Neocomian in its restricted sense. Adolf von Koenen and other German geologists extend the use of the term to include the whole of the Lower Cretaceous up to the top of the Gault or Albian. Eugène Renevier divided the Lower Cretaceous into the Neocomian division, embracing the three sub-stages mentioned above, and an Urgonian division, including the Barremian, Rhodanian and Aptian sub-stages. Sir A. Geikie (Text Book of Geology, 4th ed., 1903) regards Neocomian as synonymous with Lower Cretaceous, and he, like Renevier, closes this portion of the system at the top of the Lower Greensand (Aptian). Other British geologists (A. J. Jukes-Browne, &c.) restrict the Neocomian to the marine beds of Speeton and Tealby, and their estuarine equivalents, the Weald Clay and Hastings Sands (Wealden). Much confusion would be avoided by dropping the term Neocomian entirely and employing instead, for the type area, the sub-divisions given above. This becomes the more obvious when it is pointed out that the Berriasian type is limited to Dauphine; the Valanginian has not a much wider range; and the Hauterivian does not extend north of the Paris basin.

Characteristic fossils of the Berriasian are Hoplites euthymi, H. occitanicus; of the Valanginian, Natica leviathan, Belémnites pistilliformis and B. dilatatus, Oxynoticeras Gevrili; of the Hauterivian, Hoplites radiatus, Crioceras capricornu, Exogyra Couloni and Toxaster complanatus. The marine equivalents of these rocks in England are the lower Speeton Clays of Yorkshire and the Tealby beds of Lincolnshire. The Wealden beds of southern England represent approximately an estuarine phase of deposit of the same age. The Hils clay of Germany and Wealden of Hanover; the limestones and shales of Teschen; the Aptychus and Pygope diphyoides marls of Spain, and the Petchorian formation of Russia are equivalents of the Neocomian in its narrower sense.

References

1. 
   

1. "Neocomian". A Dictionary of Earth Sciences. n.d. Retrieved 2022-05-01 – via Oxford Reference.

•  This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Neocomian". Encyclopædia Britannica (11th ed.). Cambridge University Press.

Categories:

• Cretaceous geochronology
• Stratigraphy

https://en.wikipedia.org/wiki/Neocomian

The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared.  

https://en.wikipedia.org/wiki/Cretaceous

From Wikipedia, the free encyclopedia

"Extinction of dinosaurs" redirects here. For other uses, see Extinction event.

Clockwise from top left:

• Artist's rendering of an asteroid a few kilometers across colliding with the Earth. Such an impact can release the equivalent energy of several million nuclear weapons detonating simultaneously;
• Bali Khila, an eroded hill from the Deccan Traps, which are another hypothesized cause of the K-Pg extinction event;
• Badlands near Drumheller, Alberta, where erosion has exposed the K–Pg boundary;
• Complex Cretaceous–Paleogene clay layer (gray) in the Geulhemmergroeve tunnels near Geulhem, The Netherlands (finger is below the actual Cretaceous–Paleogene boundary);
• Wyoming rock with an intermediate claystone layer that contains 1,000 times more iridium than the upper and lower layers. Picture taken at the San Diego Natural History Museum.

The Cretaceous–Paleogene (K–Pg) extinction event,^[a] also known as the Cretaceous–Tertiary (K–T) extinction,^[b] was a sudden mass extinction of three-quarters of the plant and animal species on Earth,^[2][3] approximately 66 million years ago. The event caused the extinction of all non-avian dinosaurs. Most other tetrapods weighing more than 25 kilograms (55 pounds) also became extinct, with the exception of some ectothermic species such as sea turtles and crocodilians.^[4] It marked the end of the Cretaceous Period, and with it the Mesozoic era, while heralding the beginning of the Cenozoic era, which continues to this day.

In the geologic record, the K–Pg event is marked by a thin layer of sediment called the K–Pg boundary, which can be found throughout the world in marine and terrestrial rocks. The boundary clay shows unusually high levels of the metal iridium,^[5][6][7] which is more common in asteroids than in the Earth's crust.^[8]

As originally proposed in 1980^[9] by a team of scientists led by Luis Alvarez and his son Walter, it is now generally thought that the K–Pg extinction was caused by the impact of a massive asteroid 10 to 15 km (6 to 9 mi) wide,^[10][11] 66 million years ago, which devastated the global environment, mainly through a lingering impact winter which halted photosynthesis in plants and plankton.^[12][13] The impact hypothesis, also known as the Alvarez hypothesis, was bolstered by the discovery of the 180 km (112 mi) Chicxulub crater in the Gulf of Mexico's Yucatán Peninsula in the early 1990s,^[14] which provided conclusive evidence that the K–Pg boundary clay represented debris from an asteroid impact.^[8] The fact that the extinctions occurred simultaneously provides strong evidence that they were caused by the asteroid.^[8] A 2016 drilling project into the Chicxulub peak ring confirmed that the peak ring comprised granite ejected within minutes from deep in the earth, but contained hardly any gypsum, the usual sulfate-containing sea floor rock in the region: the gypsum would have vaporized and dispersed as an aerosol into the atmosphere, causing longer-term effects on the climate and food chain. In October 2019, researchers reported that the event rapidly acidified the oceans, producing ecological collapse and, in this way as well, produced long-lasting effects on the climate, and accordingly was a key reason for the mass extinction at the end of the Cretaceous.^[15][16]

Other causal or contributing factors to the extinction may have been the Deccan Traps and other volcanic eruptions,^[17][18] climate change, and sea level change. However, in January 2020, scientists reported that climate-modeling of the extinction event favored the asteroid impact and not volcanism.^[19][20][21]

A wide range of terrestrial species perished in the K–Pg extinction, the best-known being the non-avian dinosaurs, along with many mammals, birds,^[22] lizards,^[23] insects,^[24][25] plants, and all the pterosaurs.^[26] In the oceans, the K–Pg extinction killed off plesiosaurs and mosasaurs and devastated teleost fish,^[27] sharks, mollusks (especially ammonites, which became extinct), and many species of plankton. It is estimated that 75% or more of all species on Earth vanished.^[28] However, the extinction also provided evolutionary opportunities: in its wake, many groups underwent remarkable adaptive radiation—sudden and prolific divergence into new forms and species within the disrupted and emptied ecological niches. Mammals in particular diversified in the Paleogene,^[29] evolving new forms such as horses, whales, bats, and primates. The surviving group of dinosaurs were avians, a few species of ground and water fowl, which radiated into all modern species of birds.^[30] Among other groups, teleost fish^[31] and perhaps lizards^[23] also radiated. 

https://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_extinction_event

From Wikipedia, the free encyclopedia

Badlands near Drumheller, Alberta, Canada, where glacial and post-glacial erosion have exposed the K–Pg boundary along with much other sedimentation (the exact boundary is a thin line not obviously visible).

Complex Cretaceous-Paleogene clay layer (gray) in the Geulhemmergroeve tunnels near Geulhem, the Netherlands. Finger is on the actual K–Pg boundary.

The Cretaceous–Paleogene (K–Pg) boundary, formerly known as the Cretaceous–Tertiary (K–T) boundary,^[a] is a geological signature, usually a thin band of rock containing much more iridium than other bands. The K–Pg boundary marks the end of the Cretaceous Period, the last period of the Mesozoic Era, and marks the beginning of the Paleogene Period, the first period of the Cenozoic Era. Its age is usually estimated at around 66 million years,^[2] with radiometric dating yielding a more precise age of 66.043 ± 0.011 Ma.^[3]

The K–Pg boundary is associated with the Cretaceous–Paleogene extinction event, a mass extinction which destroyed a majority of the world's Mesozoic species, including all dinosaurs except for birds.^[4]

Strong evidence exists that the extinction coincided with a large meteorite impact at the Chicxulub crater and the generally accepted scientific theory is that this impact triggered the extinction event.

The word "Cretaceous" is derived from the Latin "creta" (chalk). It is abbreviated K (as in "K–Pg boundary") for its German translation "Kreide" (chalk).^[5]

Proposed causes

Chicxulub crater

Chicxulub crater
Chicxulub impact structure
Imaging from NASA's Shuttle Radar Topography Mission STS-99 reveals part of the 180 km (110 mi) diameter ring of the crater. The numerous sinkholes clustered around the trough of the crater suggest a prehistoric oceanic basin in the depression left by the impact.[6]
Impact crater/structure
Confidence	Confirmed
Diameter	150 km (93 mi)
Depth	20 km (12 mi)
Impactor diameter	10–15 km (6.2–9.3 mi)
Age	66.043 ± 0.011 Ma Cretaceous–Paleogene boundary[7]
Exposed	No
Drilled	Yes
Bolide type	Carbonaceous chondrite
Location
Coordinates	21°24′0″N 89°31′0″W
Country	Mexico
State	Yucatán
Chicxulub crater Location of Chicxulub crater

Main article: Chicxulub crater

Luis (left) and his son Walter Alvarez (right) at the K-T Boundary in Gubbio, Italy, 1981

In 1980, a team of researchers led by Nobel prize-winning physicist Luis Alvarez, his son, geologist Walter Alvarez, and chemists Frank Asaro and Helen Vaughn Michel discovered that sedimentary layers found all over the world at the Cretaceous–Paleogene boundary contain a concentration of iridium hundreds of times greater than normal. They suggested that this layer was evidence of an impact event that triggered worldwide climate disruption and caused the Cretaceous–Paleogene extinction event, a mass extinction in which 75% of plant and animal species on Earth suddenly became extinct, including all non-avian dinosaurs.^[8]

When it was originally proposed, one issue with the "Alvarez hypothesis" (as it came to be known) was that no documented crater matched the event. This was not a lethal blow to the theory; while the crater resulting from the impact would have been larger than 250 km (160 mi) in diameter, Earth's geological processes hide or destroy craters over time.^[9]

The Chicxulub crater is an impact crater buried underneath the Yucatán Peninsula in Mexico.^[10] Its center is located near the town of Chicxulub, after which the crater is named.^[11] It was formed by a large asteroid or comet about 10–15 km (6.2–9.3 mi) in diameter,^[12][13] the Chicxulub impactor, striking the Earth. The date of the impact coincides precisely with the Cretaceous–Paleogene boundary (K–Pg boundary), slightly more than 66 million years ago.^[7]

The crater is estimated to be over 150 km (93 mi) in diameter^[10] and 20 km (12 mi) in depth, well into the continental crust of the region of about 10–30 km (6.2–18.6 mi) depth. It makes the feature the second of the largest confirmed impact structures on Earth, and the only one whose peak ring is intact and directly accessible for scientific research.^[14]

The crater was discovered by Antonio Camargo and Glen Penfield, geophysicists who had been looking for petroleum in the Yucatán during the late 1970s. Penfield was initially unable to obtain evidence that the geological feature was a crater and gave up his search. Later, through contact with Alan Hildebrand in 1990, Penfield obtained samples that suggested it was an impact feature. Evidence for the impact origin of the crater includes shocked quartz,^[15] a gravity anomaly, and tektites in surrounding areas.

In 2016, a scientific drilling project drilled deep into the peak ring of the impact crater, hundreds of meters below the current sea floor, to obtain rock core samples from the impact itself. The discoveries were widely seen as confirming current theories related to both the crater impact and its effects.

The shape and location of the crater indicate further causes of devastation in addition to the dust cloud. The asteroid landed right on the coast and would have caused gigantic tsunamis, for which evidence has been found all around the coast of the Caribbean and eastern United States—marine sand in locations which were then inland, and vegetation debris and terrestrial rocks in marine sediments dated to the time of the impact.^[16][17]

The asteroid landed in a bed of anhydrite (CaSO
₄) or gypsum (CaSO₄·2(H₂O)), which would have ejected large quantities of sulfur trioxide SO
₃ that combined with water to produce a sulfuric acid aerosol. This would have further reduced the sunlight reaching the Earth's surface and then over several days, precipitated planet-wide as acid rain, killing vegetation, plankton and organisms which build shells from calcium carbonate (coccolithophorids and molluscs).^[18][19]

Deccan Traps

Main article: Deccan Traps

Before 2000, arguments that the Deccan Traps flood basalts caused the extinction were usually linked to the view that the extinction was gradual, as the flood basalt events were thought to have started around 68 Ma and lasted for over 2 million years. However, there is evidence that two thirds of the Deccan Traps were created within 1 million years about 65.5 Ma, so these eruptions would have caused a fairly rapid extinction, possibly a period of thousands of years, but still a longer period than what would be expected from a single impact event.^[20][21]

The Deccan Traps could have caused extinction through several mechanisms, including the release of dust and sulfuric aerosols into the air which might have blocked sunlight and thereby reduced photosynthesis in plants. In addition, Deccan Trap volcanism might have resulted in carbon dioxide emissions which would have increased the greenhouse effect when the dust and aerosols cleared from the atmosphere.^[21]

In the years when the Deccan Traps theory was linked to a slower extinction, Luis Alvarez (who died in 1988) replied that paleontologists were being misled by sparse data. While his assertion was not initially well-received, later intensive field studies of fossil beds lent weight to his claim. Eventually, most paleontologists began to accept the idea that the mass extinctions at the end of the Cretaceous were largely or at least partly due to a massive Earth impact. However, even Walter Alvarez has acknowledged that there were other major changes on Earth even before the impact, such as a drop in sea level and massive volcanic eruptions that produced the Indian Deccan Traps, and these may have contributed to the extinctions.^[22]

Multiple impact event

Several other craters also appear to have been formed about the time of the K–Pg boundary. This suggests the possibility of nearly simultaneous multiple impacts, perhaps from a fragmented asteroidal object, similar to the Shoemaker–Levy 9 cometary impact with Jupiter. Among these are the Boltysh crater, a 24 km (15 mi) diameter impact crater in Ukraine (65.17 ± 0.64 Ma); and the Silverpit crater, a 20 km (12 mi) diameter impact crater in the North Sea (60–65 Ma). Any other craters that might have formed in the Tethys Ocean would have been obscured by erosion and tectonic events such as the relentless northward drift of Africa and India.^[23][24][25]

A very large structure in the sea floor off the west coast of India was interpreted in 2006 as a crater by three researchers.^[26] The potential Shiva crater, 450–600 km (280–370 mi) in diameter, would substantially exceed Chicxulub in size and has been estimated to be about 66 mya, an age consistent with the K–Pg boundary. An impact at this site could have been the triggering event for the nearby Deccan Traps.^[27] However, this feature has not yet been accepted by the geologic community as an impact crater and may just be a sinkhole depression caused by salt withdrawal.^[25]

Maastrichtian marine regression

Clear evidence exists that sea levels fell in the final stage of the Cretaceous by more than at any other time in the Mesozoic era. In some Maastrichtian stage rock layers from various parts of the world, the later ones are terrestrial; earlier ones represent shorelines and the earliest represent seabeds. These layers do not show the tilting and distortion associated with mountain building; therefore, the likeliest explanation is a regression, that is, a buildout of sediment, but not necessarily a drop in sea level. No direct evidence exists for the cause of the regression, but the explanation which is currently accepted as the most likely is that the mid-ocean ridges became less active and therefore sank under their own weight as sediment from uplifted orogenic belts filled in structural basins.^[28][29]

A severe regression would have greatly reduced the continental shelf area, which is the most species-rich part of the sea, and therefore could have been enough to cause a marine mass extinction. However, research concludes that this change would have been insufficient to cause the observed level of ammonite extinction. The regression would also have caused climate changes, partly by disrupting winds and ocean currents and partly by reducing the Earth's albedo and therefore increasing global temperatures.^[30]

Marine regression also resulted in the reduction in area of epeiric seas, such as the Western Interior Seaway of North America. The reduction of these seas greatly altered habitats, removing coastal plains that ten million years before had been host to diverse communities such as are found in rocks of the Dinosaur Park Formation. Another consequence was an expansion of freshwater environments, since continental runoff now had longer distances to travel before reaching oceans. While this change was favorable to freshwater vertebrates, those that prefer marine environments, such as sharks, suffered.^[31]

Supernova hypothesis

Another discredited cause for the K–Pg extinction event is cosmic radiation from a nearby supernova explosion. An iridium anomaly at the boundary is consistent with this hypothesis. However, analysis of the boundary layer sediments failed to find ²⁴⁴
Pu,^[32] a supernova byproduct^{[clarification needed]} which is the longest-lived plutonium isotope, with a half-life of 81 million years.

Verneshot

An attempt to link volcanism - like the Deccan Traps - and impact events causally in the other direction compared to the proposed Shiva crater is the so-called Verneshot hypothesis (named for Jules Verne), which proposes that volcanism might have gotten so intense as to "shoot up" material into a ballistic trajectory into space before it fell down as an impactor. Due to the spectacular nature of this proposed mechanism, the scientific community has largely reacted with skepticism to this hypothesis.

Multiple causes

It is possible that more than one of these hypotheses may be a partial solution to the mystery, and that more than one of these events may have occurred. Both the Deccan Traps and the Chicxulub impact may have been important contributors. For example, the most recent dating of the Deccan Traps supports the idea that rapid eruption rates in the Deccan Traps may have been triggered by large seismic waves radiated by the impact.^[33][34]

See also

• Climate across Cretaceous-Paleogene boundary
• Sub-Paleogene surface
• Tanis (fossil site)

References and notes

Explanatory notes

1. 
   

1. This former designation has as a part of it a term, 'Tertiary' (abbreviated as T), that is now discouraged as a formal geochronological unit by the International Commission on Stratigraphy.^[1]

References

1. 
   

Gradstein, Felix M.; Ogg, James G.; Smith, Alan G., eds. (2004). A geologic time scale 2004. Cambridge, UK: Cambridge University Press. ISBN 978-0-521-78142-8.

"International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. 2012. Archived from the original (PDF) on 2013-07-17. Retrieved 2013-12-18.

Renne; et al. (2013). "Time Scales of Critical Events Around the Cretaceous-Paleogene Boundary". Science. 339 (6120): 684–7. Bibcode:2013Sci...339..684R. doi:10.1126/science.1230492. PMID 23393261. S2CID 6112274.

Fortey, R (1999). Life: A Natural History of the First Four Billion Years of Life on Earth. Vintage. pp. 238–260. ISBN 978-0-375-70261-7.

"Cretaceous Period". 15 April 2014.

"PIA03379: Shaded Relief with Height as Color, Yucatan Peninsula, Mexico". Shuttle Radar Topography Mission. NASA. Retrieved October 28, 2010.

Renne, P. R.; Deino, A. L.; Hilgen, F. J.; Kuiper, K. F.; Mark, D. F.; Mitchell, W. S.; Morgan, L. E.; Mundil, R.; Smit, J. (2013). "Time Scales of Critical Events Around the Cretaceous-Paleogene Boundary" (PDF). Science. 339 (6120): 684–687. Bibcode:2013Sci...339..684R. doi:10.1126/science.1230492. ISSN 0036-8075. PMID 23393261. S2CID 6112274.

Alvarez, L.W.; Alvarez, W.; Asaro, F.; Michel, H. V. (1980). "Extraterrestrial cause for the Cretaceous–Tertiary extinction". Science. 208 (4448): 1095–1108. Bibcode:1980Sci...208.1095A. CiteSeerX 10.1.1.126.8496. doi:10.1126/science.208.4448.1095. PMID 17783054. S2CID 16017767.

Keller G, Adatte T, Stinnesbeck W, Rebolledo-Vieyra, Fucugauchi JU, Kramar U, Stüben D (2004). "Chicxulub impact predates the K-T boundary mass extinction". PNAS. 101 (11): 3753–3758. Bibcode:2004PNAS..101.3753K. doi:10.1073/pnas.0400396101. PMC 374316. PMID 15004276.

"Chicxulub". Earth Impact Database. Planetary and Space Science Centre University of New Brunswick Fredericton. Retrieved December 30, 2008.

Penfield, Glen. Interview: The Dinosaurs: Death of the Dinosaur. 1992, WHYY.

Schulte, P.; Alegret, L.; Arenillas, I.; et al. (2010). "The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundary" (PDF). Science. 327 (5970): 1214–18. Bibcode:2010Sci...327.1214S. doi:10.1126/science.1177265. ISSN 0036-8075. PMID 20203042. S2CID 2659741. Archived from the original (PDF) on December 9, 2011. Retrieved 9 December 2016.

Amos, Jonathan (May 15, 2017). "Dinosaur asteroid hit 'worst possible place'". BBC News.

St. Fleur, Nicholas (17 November 2016). "Drilling Into the Chicxulub Crater, Ground Zero of the Dinosaur Extinction". The New York Times. Retrieved 4 November 2017.

Becker, Luann (2002). "Repeated Blows" (PDF). Scientific American. 286 (3): 76–83. Bibcode:2002SciAm.286c..76B. doi:10.1038/scientificamerican0302-76. PMID 11857903. Retrieved January 28, 2016.

Smit, J.; Roep, T.B.; Alvarez, W.; Montanari, A.; Claeys, P.; Grajales-Nishimura, J.M.; Bermudez, J. (1996). "Coarse-grained, clastic sandstone complex at the K/T boundary around the Gulf of Mexico: Deposition by tsunami waves induced by the Chicxulub impact?" (PDF). Geological Society of America Special Papers. 307: 151–182. Retrieved 19 August 2021.

Schulte, Peter; Smit, Jan; Deutsch, Alexander; Salge, Tobias; Friese, Andrea; Beichel, Kilian (April 2012). "Tsunami backwash deposits with Chicxulub impact ejecta and dinosaur remains from the Cretaceous-Palaeogene boundary in the La Popa Basin, Mexico: Cretaceous-Palaeogene event deposit, La Popa Basin, Mexico". Sedimentology. 59 (3): 737–765. doi:10.1111/j.1365-3091.2011.01274.x. S2CID 131038473.

Dinosaur-Killing Asteroid Triggered Lethal Acid Rain, Livescience, March 09, 2014

Ohno, Sohsuke; Kadono, Toshihiko; Kurosawa, Kosuke; Hamura, Taiga; Sakaiya, Tatsuhiro; Shigemori, Keisuke; Hironaka, Yoichiro; Sano, Takayoshi; Watari, Takeshi; Otani, Kazuto; Matsui, Takafumi; Sugita, Seiji (April 2014). "Production of sulphate-rich vapour during the Chicxulub impact and implications for ocean acidification". Nature Geoscience. 7 (4): 279–282. Bibcode:2014NatGe...7..279O. doi:10.1038/ngeo2095.

Hofman C, Féraud G, Courtillot V (2000). "40Ar/39Ar dating of mineral separates and whole rocks from the Western Ghats lava pile: further constraints on duration and age of the Deccan traps". Earth and Planetary Science Letters. 180 (1–2): 13–27. Bibcode:2000E&PSL.180...13H. doi:10.1016/S0012-821X(00)00159-X.

Duncan, RA; Pyle, DG (1988). "Rapid eruption of the Deccan flood basalts at the Cretaceous/Tertiary boundary". Nature. 333 (6176): 841–843. Bibcode:1988Natur.333..841D. doi:10.1038/333841a0. S2CID 4351454.

Alvarez, W (1997). T. rex and the Crater of Doom. Princeton University Press. pp. 130–146. ISBN 978-0-691-01630-6.

Mullen, L (October 13, 2004). "Debating the Dinosaur Extinction". Astrobiology Magazine. Archived from the original on 2011-06-03. Retrieved 2007-07-11.

Mullen, L (October 20, 2004). "Multiple impacts". Astrobiology Magazine. Archived from the original on 2008-07-09. Retrieved 2007-07-11.

Mullen, L (November 3, 2004). "Shiva: Another K–T impact?". Astrobiology Magazine. Archived from the original on 2011-08-04. Retrieved 2007-07-11.

Chatterjee, S; Guven, N; Yoshinobu, A & Donofrio, R (2006). "Shiva structure: a possible K-Pg boundary impact crater on the western shelf of India" (PDF). Special Publications of the Museum of Texas Tech University (50). Retrieved 2007-06-15.

Chatterjee, S; Guven, N; Yoshinobu, A & Donofrio, R (2003). "The Shiva Crater: Implications for Deccan Volcanism, India-Seychelles rifting, dinosaur extinction, and petroleum entrapment at the KT Boundary". Geological Society of America Abstracts with Programs. 35 (6): 168. Retrieved 2007-08-02.

MacLeod, N.; Rawson, P.F.; et al. (1997). "The Cretaceous–Tertiary biotic transition". Journal of the Geological Society. 154 (2): 265–292. Bibcode:1997JGSoc.154..265M. doi:10.1144/gsjgs.154.2.0265. ISSN 0016-7649. S2CID 129654916.

Liangquan, Li; Keller, Gerta (1998). "Abrupt deep-sea warming at the end of the Cretaceous". Geology. 26 (11): 995–8. Bibcode:1998Geo....26..995L. doi:10.1130/0091-7613(1998)026<0995:ADSWAT>2.3.CO;2.

Marshall, C. R.; Ward, P.D. (1996). "Sudden and Gradual Molluscan Extinctions in the Latest Cretaceous of Western European Tethys". Science. 274 (5291): 1360–1363. Bibcode:1996Sci...274.1360M. doi:10.1126/science.274.5291.1360. PMID 8910273. S2CID 1837900.

Archibald, J. David; Fastovsky, David E. (2004). "Dinosaur Extinction". In Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (eds.). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 672–684. ISBN 978-0-520-24209-8.

Ellis, J; Schramm, DN (1995). "Could a Nearby Supernova Explosion have Caused a Mass Extinction?". Proceedings of the National Academy of Sciences. 92 (1): 235–238. arXiv:hep-ph/9303206. Bibcode:1995PNAS...92..235E. doi:10.1073/pnas.92.1.235. PMC 42852. PMID 11607506.

Richards, Mark A.; Alvarez, Walter; Self, Stephen; Karlstrom, Leif; Renne, Paul R.; Manga, Michael; Sprain, Courtney J.; Smit, Jan; Vanderkluysen, Loÿc; Gibson, Sally A. (November 2015). "Triggering of the largest Deccan eruptions by the Chicxulub impact". Geological Society of America Bulletin. 127 (11–12): 1507–1520. Bibcode:2015GSAB..127.1507R. doi:10.1130/B31167.1. S2CID 3463018.

34. Renne, Paul R.; Sprain, Courtney J.; Richards, Mark A.; Self, Stephen; Vanderkluysen, Loÿc; Pande, Kanchan (2 October 2015). "State shift in Deccan volcanism at the Cretaceous-Paleogene boundary, possibly induced by impact". Science. 350 (6256): 76–78. Bibcode:2015Sci...350...76R. doi:10.1126/science.aac7549. PMID 26430116. S2CID 30612906.

External links

• The KT Boundary on In Our Time at the BBC

• Sanders, Robert (29 March 2019). "66 million-year-old deathbed linked to dinosaur-killing meteor". Berkeley News.
• Preston, Douglas (29 March 2019). "The day the dinosaurs died". New Yorker.

v t e Cretaceous–Paleogene extinction event

v t e Impact cratering on Earth

Categories:

• Earth Impact Database
• Cretaceous–Paleogene boundary
• Cretaceous geology
• Events that forced the climate
• Extinction events
• Impact geology
• Paleogene geology
• Volcanism

 https://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_boundary

 

• Article
• Talk

• Read
• Edit
• View history

Tools

• 
  
• 
  
• 
  
• 
  
• 
  
• 
  
• 
  
• 
  

• 
  
• 
  

• 
  

From Wikipedia, the free encyclopedia

This article is about the sedimentary rock. For other uses, see Chalk (disambiguation).

Chalk

Sedimentary rock
Beachy Head is a part of the extensive Southern England Chalk Formation.
Composition
Calcite (calcium carbonate)

Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor. Chalk is common throughout Western Europe, where deposits underlie parts of France, and steep cliffs are often seen where they meet the sea in places such as the Dover cliffs on the Kent coast of the English Channel.

Chalk is mined for use in industry, such as for quicklime, bricks and builder's putty, and in agriculture, for raising pH in soils with high acidity. It is also used for "blackboard chalk" for writing and drawing on various types of surfaces, although these can also be manufactured from other carbonate-based minerals, or gypsum. 

https://en.wikipedia.org/wiki/Chalk

Coccolith

• Article
• Talk

• Read
• Edit
• View history

Tools

• 
  
• 
  
• 
  
• 
  
• 
  
• 
  
• 
  
• 
  

• 
  
• 
  

• 
  

From Wikipedia, the free encyclopedia

(Redirected from Coccoliths)

Scanning electron micrograph of Coccolithus pelagicus, plated with coccoliths

Coccoliths are individual plates or scales of calcium carbonate formed by coccolithophores (single-celled phytoplankton such as Emiliania huxleyi) and cover the cell surface arranged in the form of a spherical shell, called a coccosphere.

Overview

Coccolithophores are spherical cells about 5–100 micrometres across, enclosed by calcareous plates called coccoliths, which are about 2–25 micrometres across.^[1] Coccolithophores are an important group of about 200 marine phytoplankton species ^[2] which cover themselves with a calcium carbonate shell called a "coccosphere". They are ecologically and biogeochemically important but the reason why they calcify remains elusive. One key function may be that the coccosphere offers protection against microzooplankton predation, which is one of the main causes of phytoplankton death in the ocean.^[3]

• 

  Partial cross section of a coccolithophore with coccolith layer ^[4]

• 

  Coccolithophore cell surrounded by its shield of coccoliths. The coccolith-bearing cell is called the coccosphere.^[5][6]

Coccolithophores have been an integral part of marine plankton communities since the Jurassic.^[7][8] Today, coccolithophores contribute ~1–10% to primary production in the surface ocean ^[9] and ~50% to pelagic CaCO₃ sediments.^[10] Their calcareous shell increases the sinking velocity of photosynthetically fixed CO₂ into the deep ocean by ballasting organic matter.^[11][12] At the same time, the biogenic precipitation of calcium carbonate during coccolith formation reduces the total alkalinity of seawater and releases CO₂.^[13][14] Thus, coccolithophores play an important role in the marine carbon cycle by influencing the efficiency of the biological carbon pump and the oceanic uptake of atmospheric CO₂.^[3]

As of 2021, it is not known why coccolithophores calcify and how their ability to produce coccoliths is associated with their ecological success.^{[15][16][17][18][19]} The most plausible benefit of having a coccosphere seems to be a protection against predators or viruses.^[20][18] Viral infection is an important cause of phytoplankton death in the oceans,^[21] and it has recently been shown that calcification can influence the interaction between a coccolithophore and its virus.^[22][23] The major predators of marine phytoplankton are microzooplankton like ciliates and dinoflagellates. These are estimated to consume about two-thirds of the primary production in the ocean ^[24] and microzooplankton can exert a strong grazing pressure on coccolithophore populations.^[25] Although calcification does not prevent predation, it has been argued that the coccosphere reduces the grazing efficiency by making it more difficult for the predator to utilise the organic content of coccolithophores.^[26] Heterotrophic protists are able to selectively choose prey on the basis of its size or shape and through chemical signals ^[27][28] and may thus favor other prey that is available and not protected by coccoliths.^[3]

Formation and composition

Part of a series related to
Biomineralization

General

Exoskeletons (shells)

Endoskeletons (bones)

Teeth, scales, tusks etc

Calcification

Silicification

Other forms

Related

Category

v t e

Coccoliths are formed within the cell in vesicles derived from the golgi body. When the coccolith is complete these vesicles fuse with the cell wall and the coccolith is exocytosed and incorporated in the coccosphere. The coccoliths are either dispersed following death and breakup of the coccosphere, or are shed continually by some species. They sink through the water column to form an important part of the deep-sea sediments (depending on the water depth). Thomas Huxley was the first person to observe these forms in modern marine sediments and he gave them the name 'coccoliths' in a report published in 1858.^[29][30] Coccoliths are composed of calcium carbonate as the mineral calcite and are the main constituent of chalk deposits such as the white cliffs of Dover (deposited in Cretaceous times), in which they were first described by Henry Clifton Sorby in 1861.^[31]

• 

  Collapsed coccosphere of Pleurochrysis carterae

Types

There are two main types of coccoliths, heterococcoliths and holococcoliths. Heterococcoliths are formed of a radial array of elaborately shaped crystal units. Holococcoliths are formed of minute (~0.1 micrometre) calcite rhombohedra, arranged in continuous arrays. The two coccolith types were originally thought to be produced by different families of coccolithophores. Now, however, it is known through a mix of observations on field samples and laboratory cultures, that the two coccolith types are produced by the same species but at different life cycle phases. Heterococcoliths are produced in the diploid life-cycle phase and holococcoliths in the haploid phase. Both in field samples and laboratory cultures, there is the possibility of observing a cell covered by a combination of heterococcoliths and holococcoliths. This indicates the transition from the diploid to the haploid phase of the species. Such combination of coccoliths has been observed in field samples, with many of them coming from the Mediterranean.^[32][33]

Types of cocoliths

Shape

Coccoliths are also classified depending on shape. Common shapes include:^[34][35]

• Calyptrolith – basket-shaped with openings near the base
• Caneolith – disc- or bowl-shaped
• Ceratolith – horseshoe or wishbone shaped
• Cribrilith – disc-shaped, with numerous perforations in the central area
• Cyrtolith – convex disc shaped, may with a projecting central process
• Discolith – ellipsoidal with a raised rim, in some cases the high rim forms a vase or cup-like structure
• Helicolith – a placolith with a spiral margin
• Lopadolith – basket or cup-shaped with a high rim, opening distally
• Pentalith – pentagonal shape composed of five four-sided crystals
• Placolith – rim composed of two plates stacked on top of one another
• Prismatolith – polygonal, may have perforations
• Rhabdolith – a single plate with a club-shaped central process
• Scapholith – rhombohedral, with parallel lines in center

Helicoliths of Helicosphaera carteri

Coccosphere of Emiliania huxleyi consisting of overlapping placoliths

• 

  Coccolith structures of representative Noelaerhabdaceae.^[36]
  Each morphospecies is associated with a SEM image in the next diagram

• 

  SEM images correspond to coccolith drawings in the previous diagram
  (A) Gephyrocapsa ericsonii RCC4032 (B) Gephyrocapsa muellerae (C) Gephyrocapsa oceanica (D) Reticulofenestra parvular RCC4033; (E) Reticulofenestra parvular RCC4034; (F) Reticulofenestra parvular RCC4035; (G) Reticulofenestra parvular RCC4036; (H) Emiliania huxleyi morphotype R; (I) Emiliania huxleyi morphotype A; (J) Emiliania huxleyi morphotype B.

Function

Although coccoliths are remarkably elaborate structures whose formation is a complex product of cellular processes, their function is unclear. Hypotheses include defence against grazing by zooplankton or infection by bacteria or viruses; maintenance of buoyancy; release of carbon dioxide for photosynthesis; to filter out harmful UV light; or in deep-dwelling species, to concentrate light for photosynthesis.

Fossil record

Because coccoliths are formed of low-Mg calcite, the most stable form of calcium carbonate, they are readily fossilised. They are found in sediments together with similar microfossils of uncertain affinities (nanoliths) from the Upper Triassic to recent. They are widely used as biostratigraphic markers and as paleoclimatic proxies. Coccoliths and related fossils are referred to as calcareous nanofossils or calcareous nannoplankton (nanoplankton).

References

1. 
   

Moheimani, N.R.; Webb, J.P.; Borowitzka, M.A. (2012), "Bioremediation and other potential applications of coccolithophorid algae: A review. . Bioremediation and other potential applications of coccolithophorid algae: A review", Algal Research, 1 (2): 120–133, doi:10.1016/j.algal.2012.06.002

Young, J. R.; Geisen, M.; Probert, I. (2005). "A review of selected aspects of coccolithophore biology with implications for paleobiodiversity estimation" (PDF). Micropaleontology. 51 (4): 267–288. doi:10.2113/gsmicropal.51.4.267.

Haunost, Mathias; Riebesell, Ulf; D'Amore, Francesco; Kelting, Ole; Bach, Lennart T. (30 June 2021). "Influence of the Calcium Carbonate Shell of Coccolithophores on Ingestion and Growth of a Dinoflagellate Predator". Frontiers in Marine Science. Frontiers Media SA. 8. doi:10.3389/fmars.2021.664269. ISSN 2296-7745. Material was copied from this source, which is available under a Creative Commons Attribution 4.0 International License.

Irie, Takahiro; Bessho, Kazuhiro; Findlay, Helen S.; Calosi, Piero (2010-10-15). "Increasing Costs Due to Ocean Acidification Drives Phytoplankton to Be More Heavily Calcified: Optimal Growth Strategy of Coccolithophores". PLoS ONE. Public Library of Science (PLoS). 5 (10): e13436. doi:10.1371/journal.pone.0013436. ISSN 1932-6203. Modified material was copied from this source, which is available under a Creative Commons Attribution 4.0 International License.

Aloisi, G. (6 August 2015). "Covariation of metabolic rates and cell size in coccolithophores". Biogeosciences. Copernicus GmbH. 12 (15): 4665–4692. Bibcode:2015BGeo...12.4665A. doi:10.5194/bg-12-4665-2015. ISSN 1726-4189. S2CID 6227548.

Henderiks, Jorijntje (2008). "Coccolithophore size rules — Reconstructing ancient cell geometry and cellular calcite quota from fossil coccoliths". Marine Micropaleontology. Elsevier BV. 67 (1–2): 143–154. Bibcode:2008MarMP..67..143H. doi:10.1016/j.marmicro.2008.01.005. ISSN 0377-8398.

Bown, Paul R.; Lees, Jackie A.; Young, Jeremy R. (2004). "Calcareous nannoplankton evolution and diversity through time". Coccolithophores. pp. 481–508. doi:10.1007/978-3-662-06278-4_18. ISBN 978-3-642-06016-8.

Hay, William W. (2004). "Carbonate fluxes and calcareous nannoplankton". Coccolithophores. pp. 509–528. doi:10.1007/978-3-662-06278-4_19. ISBN 978-3-642-06016-8.

Poulton, Alex J.; Adey, Tim R.; Balch, William M.; Holligan, Patrick M. (2007). "Relating coccolithophore calcification rates to phytoplankton community dynamics: Regional differences and implications for carbon export". Deep Sea Research Part II: Topical Studies in Oceanography. 54 (5–7): 538–557. Bibcode:2007DSRII..54..538P. doi:10.1016/j.dsr2.2006.12.003.

Broecker, Wallace; Clark, Elizabeth (2009). "Ratio of coccolith CaCO3to foraminifera CaCO3in late Holocene deep sea sediments". Paleoceanography. 24 (3). Bibcode:2009PalOc..24.3205B. doi:10.1029/2009PA001731.

Klaas, Christine; Archer, David E. (2002). "Association of sinking organic matter with various types of mineral ballast in the deep sea: Implications for the rain ratio". Global Biogeochemical Cycles. 16 (4): 1116. Bibcode:2002GBioC..16.1116K. doi:10.1029/2001GB001765. S2CID 34159028.

Honjo, Susumu; Manganini, Steven J.; Krishfield, Richard A.; Francois, Roger (2008). "Particulate organic carbon fluxes to the ocean interior and factors controlling the biological pump: A synthesis of global sediment trap programs since 1983". Progress in Oceanography. 76 (3): 217–285. Bibcode:2008PrOce..76..217H. doi:10.1016/j.pocean.2007.11.003.

Frankignoulle, Michel; Canon, Christine; Gattuso, Jean-Pierre (1994). "Marine calcification as a source of carbon dioxide: Positive feedback of increasing atmospheric CO2". Limnology and Oceanography. 39 (2): 458–462. Bibcode:1994LimOc..39..458F. doi:10.4319/lo.1994.39.2.0458. hdl:2268/246251.

Rost, Björn; Riebesell, Ulf (2004). "Coccolithophores and the biological pump: Responses to environmental changes". Coccolithophores. pp. 99–125. doi:10.1007/978-3-662-06278-4_5. ISBN 978-3-642-06016-8.

Young, J. R. (1987). Possible Functional Interpretations of Coccolith Morphology. New York: Springer-Verlag, 305–313.

Young, J. R. (1994). "Functions of coccoliths," in Coccolithophores, eds A. Winter and W. G. Siesser (Cambridge: Cambridge University Press), 63–82.

Raven, JA; Crawfurd, K. (2012). "Environmental controls on coccolithophore calcification". Marine Ecology Progress Series. 470: 137–166. Bibcode:2012MEPS..470..137R. doi:10.3354/meps09993.

Monteiro, Fanny M.; Bach, Lennart T.; Brownlee, Colin; Bown, Paul; Rickaby, Rosalind E. M.; Poulton, Alex J.; Tyrrell, Toby; Beaufort, Luc; Dutkiewicz, Stephanie; Gibbs, Samantha; Gutowska, Magdalena A.; Lee, Renee; Riebesell, Ulf; Young, Jeremy; Ridgwell, Andy (2016). "Why marine phytoplankton calcify". Science Advances. 2 (7): e1501822. Bibcode:2016SciA....2E1822M. doi:10.1126/sciadv.1501822. PMC 4956192. PMID 27453937.

Müller, Marius N. (2019). "On the Genesis and Function of Coccolithophore Calcification". Frontiers in Marine Science. 6. doi:10.3389/fmars.2019.00049.

Hamm, Christian; Smetacek, Victor (2007). "Armor: Why, when, and How". Evolution of Primary Producers in the Sea. pp. 311–332. doi:10.1016/B978-012370518-1/50015-1. ISBN 9780123705181.

Brussaard, Corina P. D. (2004). "Viral Control of Phytoplankton Populations-a Review1". The Journal of Eukaryotic Microbiology. 51 (2): 125–138. doi:10.1111/j.1550-7408.2004.tb00537.x. PMID 15134247. S2CID 21017882.

Johns, Christopher T.; Grubb, Austin R.; Nissimov, Jozef I.; Natale, Frank; Knapp, Viki; Mui, Alwin; Fredricks, Helen F.; Van Mooy, Benjamin A. S.; Bidle, Kay D. (2019). "The mutual interplay between calcification and coccolithovirus infection". Environmental Microbiology. 21 (6): 1896–1915. doi:10.1111/1462-2920.14362. PMC 7379532. PMID 30043404.

Haunost, Mathias; Riebesell, Ulf; Bach, Lennart T. (2020). "The Calcium Carbonate Shell of Emiliania huxleyi Provides Limited Protection Against Viral Infection". Frontiers in Marine Science. 7. doi:10.3389/fmars.2020.530757.

Calbet, Albert; Landry, Michael R. (2004). "Phytoplankton growth, microzooplankton grazing, and carbon cycling in marine systems". Limnology and Oceanography. 49 (1): 51–57. Bibcode:2004LimOc..49...51C. doi:10.4319/lo.2004.49.1.0051. hdl:10261/134985. S2CID 22995996.

Mayers, K.M.J.; Poulton, A.J.; Daniels, C.J.; Wells, S.R.; Woodward, E.M.S.; Tarran, G.A.; Widdicombe, C.E.; Mayor, D.J.; Atkinson, A.; Giering, S.L.C. (2019). "Growth and mortality of coccolithophores during spring in a temperate Shelf Sea (Celtic Sea, April 2015)". Progress in Oceanography. 177: 101928. Bibcode:2019PrOce.17701928M. doi:10.1016/j.pocean.2018.02.024. S2CID 135347218.

Young, J. R. (1994) "Functions of coccoliths". In: Coccolithophores, Eds A. Winter and W. G. Siesser (Cambridge: Cambridge University Press), 63–82.

Tillmann, Urban (2004). "Interactions between Planktonic Microalgae and Protozoan Grazers1". The Journal of Eukaryotic Microbiology. 51 (2): 156–168. doi:10.1111/j.1550-7408.2004.tb00540.x. PMID 15134250. S2CID 36526359.

Breckels, M. N.; Roberts, E. C.; Archer, S. D.; Malin, G.; Steinke, M. (2011). "The role of dissolved infochemicals in mediating predator-prey interactions in the heterotrophic dinoflagellate Oxyrrhis marina". Journal of Plankton Research. 33 (4): 629–639. doi:10.1093/plankt/fbq114.

Huxley, Thomas Henry (1858). "Appendix A". Deep Sea Soundings in the North Atlantic Ocean between Ireland and Newfoundland, made in H.M.S. Cyclops, Lieut.-Commander Joseph Dayman, in June and July 1857. London: British Admiralty. pp. 63–68 [64].

Huxley, Thomas Henry (1868). "On some organisms living at great depth in the North Atlantic Ocean". Quarterly Journal of Microscopical Science. New series. 8: 203–212.

Sorby, Henry Clifton (1861). "On the organic origin of the so-called 'Crystalloids' of the chalk". Annals and Magazine of Natural History. Ser. 3. 8 (45): 193–200. doi:10.1080/00222936108697404.

Fortuño, José Manuel; Cros, Lluïsa (2002-03-30). "Atlas of Northwestern Mediterranean Coccolithophores". Scientia Marina. 66 (S1): 1–182. doi:10.3989/scimar.2002.66s11. ISSN 1886-8134.

Malinverno, E; Dimiza, MD; Triantaphyllou, MV; Dermitzakis, MD; Corselli, C (2008). Coccolithophores of the Eastern Mediterranean sea: A look into the marine microworld. Athens: "ION" Publishing Group. ISBN 978-960-411-660-7.

Amos Winter; William G. Siesser (2006). Coccolithophores. Cambridge University Press. pp. 54–58. ISBN 978-0-521-03169-1.

Carmelo R Tomas (2012). Marine Phytoplankton: A Guide to Naked Flagellates and Coccolithophorids. Academic Press. pp. 161–165. ISBN 978-0-323-13827-7.

36. Bendif, El Mahdi; Probert, Ian; Díaz-Rosas, Francisco; Thomas, Daniela; van den Engh, Ger; Young, Jeremy R.; von Dassow, Peter (2016-05-24). "Recent Reticulate Evolution in the Ecologically Dominant Lineage of Coccolithophores". Frontiers in Microbiology. Frontiers Media SA. 7. doi:10.3389/fmicb.2016.00784. ISSN 1664-302X. Modified material was copied from this source, which is available under a Creative Commons Attribution 4.0 International License.

External links

Wikimedia Commons has media related to Coccolith.

• The EHUX website - site dedicated to Emiliania huxleyi, containing essays on blooms, coccolith function, etc.
• International Nannoplankton Association site - includes an illustrated guide to coccolith terminology and several image galleries.
• Nannotax - illustrated guide to the taxonomy of coccolithophores and other nannofossils.
• Cocco Express - Coccolithophorids Expressed Sequence Tags (EST) & Microarray Database
• Possible functions of Coccoliths

v t e Microbiology: Protistology: Protists

Category:

• Calcium compounds

 

 https://en.wikipedia.org/wiki/Coccolith

 

Fibrodysplasia ossificans progressiva
Other names	Stone man disease, Münchmeyer disease
The effects of fibrodysplasia ossificans progressiva, a disease which causes damaged soft tissue to regrow as bone. (Skeleton of Harry Raymond Eastlack)
Specialty	Medical genetics, rheumatology
Symptoms	Continuous bone growth
Usual onset	Before age 10
Differential diagnosis	Fibrous dysplasia
Treatment	None
Prognosis	Median life expectancy ≈ 40 years old (if properly managed)
Frequency	801 confirmed cases worldwide (2017); incidence rate estimated to be 0.5 cases per million people (1 in 2 million)

Fibrodysplasia ossificans progressiva (/ˌfaɪbroʊdɪˈspleɪʒ(i)ə ɒˈsɪfɪkænz prəˈɡrɛsɪvə/;^[1] abbr. FOP), also called Münchmeyer disease or formerly myositis ossificans progressiva, is an extremely rare connective tissue disease in which fibrous connective tissue such as muscle, tendons, and ligaments turn into bone tissue. It is the only known medical condition where one organ system changes into another.^[2] It is a severe, disabling disorder with no cure or treatment.

FOP is caused by a mutation of the gene ACVR1. The mutation affects the body's repair mechanism, causing fibrous tissue including muscle, tendons, and ligaments to become ossified, either spontaneously or when damaged as the result of trauma. In many cases, otherwise minor injuries can cause joints to become permanently fused as new bone forms, replacing the damaged muscle tissue. This new bone formation (known as "heterotopic ossification") eventually forms a secondary skeleton and progressively restricts the patient's ability to move. Bone formed as a result of this process is identical to "normal" bone, simply in improper locations. Circumstantial evidence suggests that the disease can cause joint degradation separate from its characteristic bone growth.^[3]

Surgical removal of the extra bone growth has been shown to cause the body to "repair" the affected area with additional bone. Although the rate of bone growth may differ depending on the patient, the condition ultimately leaves sufferers immobilized as new bone replaces musculature and fuses with the existing skeleton. This has earned FOP the nickname "stone man disease".^[4]

^{https://en.wikipedia.org/wiki/Fibrodysplasia_ossificans_progressiva}

Protist Temporal range: Paleoproterozoic – Present Pha. Proterozoic Archean Had.
Scientific classification
Domain:	Eukaryota
Supergroups and typical phyla[1]
Amoebozoa Apusomonadida Archaeplastida (in part) Glaucophyta Rhodelphidia Rhodophyta (red algae) Picozoa Breviatea Discoba Jakobea Tsukubea Euglenozoa Percolozoa CRuMs Collodictyonidae Rigifilida Mantamonadida Cryptista Haptista Hemimastigophora Malawimonada Metamonada Meteora sporadica[2] Opisthokonta (in part) Choanoflagellata Ichthyosporea Filasterea Nucleariae Pluriformea Provora SAR Alveolata Apicomplexa Ciliophora Dinoflagellata Rhizaria Cercozoa Endomyxa Retaria Stramenopiles Gyrista (diatoms, oomycetes, brown algae...) Bigyra Platysulcea
Cladistically included but traditionally excluded taxa
Animalia (Metazoa) Fungi (Zoosporia) Plantae (Viridiplantae)

A protist (/ˈproʊtɪst/) is any eukaryotic organism (that is, an organism whose cells contain a cell nucleus) that is not an animal, plant, or fungus. Protists, along with other eukaryotes, all descend from the last eukaryotic common ancestor.^[3] Protists do not form a natural group, or clade; any unicellular eukaryote may be described as a protist,^[4] in addition to some cases of multicellular protists such as slime molds, brown algae and xenophyophorean forams.^[5] The study of protists is termed protistology.^[6] 

https://en.wikipedia.org/wiki/Protist

Emiliania huxleyi is a species of coccolithophore found in almost all ocean ecosystems from the equator to sub-polar regions, and from nutrient rich upwelling zones to nutrient poor oligotrophic waters.^[1][2][3][4] It is one of thousands of different photosynthetic plankton that freely drift in the photic zone of the ocean, forming the basis of virtually all marine food webs. It is studied for the extensive blooms it forms in nutrient-depleted waters after the reformation of the summer thermocline. Like other coccolithophores, E. huxleyi is a single-celled phytoplankton covered with uniquely ornamented calcite disks called coccoliths. Individual coccoliths are abundant in marine sediments although complete coccospheres are more unusual. In the case of E. huxleyi, not only the shell, but also the soft part of the organism may be recorded in sediments. It produces a group of chemical compounds that are very resistant to decomposition. These chemical compounds, known as alkenones, can be found in marine sediments long after other soft parts of the organisms have decomposed. Alkenones are most commonly used by earth scientists as a means to estimate past sea surface temperatures.  

https://en.wikipedia.org/wiki/Emiliania_huxleyi

Coccolithophore shells

Part of a series related to
Biomineralization

General

Exoskeletons (shells) Arthropod exoskeleton cuticle Brachiopod shell Cephalopod shell cirrate shell cuttlebone gladius Lorica Choanoflagellate lorica Protist shell coccosphere coccolith diatom frustule foraminifera test testate amoebae Seashell echinoderm stereom mollusc shell nacre chiton shell gastropod shell small shelly fauna scaly-foot snail shell estuary shells Sponge spicule Test

Endoskeletons (bones)

Teeth, scales, tusks etc

Calcification

Silicification

Other forms

Related

Category

v t e

See also: Protist shell and coccolith

• Exoskeleton: coccospheres and coccoliths

Each coccolithophore encloses itself in a protective shell of coccoliths, calcified scales which make up its exoskeleton or coccosphere.^[73] The coccoliths are created inside the coccolithophore cell and while some species maintain a single layer throughout life only producing new coccoliths as the cell grows, others continually produce and shed coccoliths.

Composition

The primary constituent of coccoliths is calcium carbonate, or chalk. Calcium carbonate is transparent, so the organisms' photosynthetic activity is not compromised by encapsulation in a coccosphere.^[45]

Formation

Coccoliths are produced by a biomineralization process known as coccolithogenesis.^[38] Generally, calcification of coccoliths occurs in the presence of light, and these scales are produced much more during the exponential phase of growth than the stationary phase.^[74] Although not yet entirely understood, the biomineralization process is tightly regulated by calcium signaling. Calcite formation begins in the golgi complex where protein templates nucleate the formation of CaCO₃ crystals and complex acidic polysaccharides control the shape and growth of these crystals.^[49] As each scale is produced, it is exported in a Golgi-derived vesicle and added to the inner surface of the coccosphere. This means that the most recently produced coccoliths may lie beneath older coccoliths.^[42] Depending upon the phytoplankton's stage in the life cycle, two different types of coccoliths may be formed. Holococcoliths are produced only in the haploid phase, lack radial symmetry, and are composed of anywhere from hundreds to thousands of similar minute (ca 0.1 μm) rhombic calcite crystals. These crystals are thought to form at least partially outside the cell. Heterococcoliths occur only in the diploid phase, have radial symmetry, and are composed of relatively few complex crystal units (fewer than 100). Although they are rare, combination coccospheres, which contain both holococcoliths and heterococcoliths, have been observed in the plankton recording coccolithophore life cycle transitions. Finally, the coccospheres of some species are highly modified with various appendages made of specialized coccoliths.^[53]

 ^{https://en.wikipedia.org/wiki/Coccolithophore#Coccolithophore_shells}

Microzooplankton

20-200μm

Major grazers of the plankton...

Microzooplankton are defined as heterotrophic and mixotrophic plankton. They primarily consist of phagotrophic protists, including ciliates, dinoflagellates, and mesozooplankton nauplii.^[23] As the primary consumers of marine phytoplankton, microzooplankton consume ~ 59–75% daily of the marine primary production, much larger than mesozooplankton. That said, macrozooplankton can sometimes have greater consumption rates in eutrophic ecosystems because the larger phytoplankton can be dominant there.^[24][25] Microzooplankton are also pivotal regenerators of nutrients which fuel primary production and food sources for metazoans.^[25][26]

Despite their ecological importance, microzooplankton remain understudied. Routine oceanographic observations seldom monitor microzooplankton biomass or herbivory rate, although the dilution technique, an elegant method of measuring microzooplankton herbivory rate, has been developed for almost four decades (Landry and Hassett 1982). The number of observations of microzooplankton herbivory rate is around 1600 globally,^[27][28] far less than that of primary productivity (> 50,000).^[29] This makes validating and optimizing the grazing function of microzooplankton difficult in ocean ecosystem models.^[26] 

https://en.wikipedia.org/wiki/Zooplankton#Microzooplankton

Hard tissue

• Article
• Talk

• Read
• Edit
• View history

Tools

• 
  
• 
  
• 
  
• 
  
• 
  
• 
  
• 
  
• 
  

• 
  
• 
  

From Wikipedia, the free encyclopedia

(Redirected from Calcify)

Hard tissue, refers to "normal" calcified tissue, is the tissue which is mineralized and has a firm intercellular matrix.^[1] The hard tissues of humans are bone, tooth enamel, dentin, and cementum.^[2] The term is in contrast to soft tissue.

Bone

Main article: Bone

Bone is a rigid organ that constitutes part of the vertebral skeleton. Bones support and protect the various organs of the body, produce red and white blood cells, store minerals and also enable mobility. Bone tissue is a type of dense connective tissue. Bones come in a variety of shapes and sizes and have a complex internal and external structure. They are lightweight yet strong and hard, and serve multiple functions. Mineralized osseous tissue or bone tissue, is of two types – cortical and cancellous and gives it rigidity and a coral-like three-dimensional internal structure. Other types of tissue found in bones include marrow, endosteum, periosteum, nerves, blood vessels and cartilage.

Bone is an active tissue composed of different cells. Osteoblasts are involved in the creation and mineralisation of bone; osteocytes and osteoclasts are involved in the reabsorption of bone tissue. The mineralised matrix of bone tissue has an organic component mainly of collagen and an inorganic component of bone mineral made up of various salts.

Enamel

Main article: Tooth enamel

Enamel is the hardest substance in the human body and contains the highest percentage of minerals,^[3] 96%, with water and organic material composing the rest.^[4] The primary mineral is hydroxyapatite, which is a crystalline calcium phosphate.^[5] Enamel is formed on the tooth while the tooth is developing within the gum, before it erupts into the mouth. Once fully formed, it does not contain blood vessels or nerves. Remineralisation of teeth can repair damage to the tooth to a certain degree but damage beyond that cannot be repaired by the body. The maintenance and repair of human tooth enamel is one of the primary concerns of dentistry.

In humans, enamel varies in thickness over the surface of the tooth, often thickest at the cusp, up to 2.5 mm, and thinnest at its border with the cementum at the cementoenamel junction.^[6]

The normal color of enamel varies from light yellow to grayish (bluish) white. At the edges of teeth where there is no dentin underlying the enamel, the color sometimes has a slightly blue tone. Since enamel is semitranslucent, the color of dentin and any material underneath the enamel strongly affects the appearance of a tooth. The enamel on primary teeth has a more opaque crystalline form and thus appears whiter than on permanent teeth.

The large amount of mineral in enamel accounts not only for its strength but also for its brittleness.^[7] Tooth enamel ranks 5 on Mohs hardness scale and has a Young's modulus of 83 GPa.^[5] Dentin, less mineralized and less brittle, 3–4 in hardness, compensates for enamel and is necessary as a support.^[8] On radiographs, the differences in the mineralization of different portions of the tooth and surrounding periodontium can be noted; enamel appears lighter than dentin or pulp since it is denser than both and more radiopaque.^[9]

Enamel does not contain collagen, as found in other hard tissues such as dentin and bone, but it does contain two unique classes of proteins: amelogenins and enamelins. While the role of these proteins is not fully understood, it is believed that they aid in the development of enamel by serving as a framework for minerals to form on, among other functions.^[7] Once it is mature, enamel is almost totally without the softer organic matter. Enamel is avascular and has no nerve supply within it and is not renewed, however, it is not a static tissue as it can undergo mineralization changes.^[10]

Dentin

Main article: Dentin

By weight, 70% of dentin consists of the mineral hydroxyapatite, 20% is organic material, and 10% is water.^[9] Yellow in appearance, it greatly affects the color of a tooth due to the translucency of enamel. Dentin, which is less mineralized and less brittle than enamel, is necessary for the support of enamel.^[11] Dentin rates approximately 3 on the Mohs scale of mineral hardness.^[12]

Cementum

Main article: Cementum

Cementum is slightly softer than dentin and consists of about 45% to 50% inorganic material (hydroxyapatite) by weight and 50% to 55% organic matter and water by weight.^[13] The organic portion is composed primarily of collagen and proteoglycans.^[14] Cementum is avascular, receiving its nutrition through its own imbedded cells from the surrounding vascular periodontal ligament.^[9]

The cementum is light yellow and slightly lighter in color than dentin. It has the highest fluoride content of all mineralized tissue. Cementum also is permeable to a variety of materials. It is formed continuously throughout life because a new layer of cementum is deposited to keep the attachment intact as the superficial layer of cementum ages. Cementum on the root ends surrounds the apical foramen and may extend slightly onto the inner wall of the pulp canal.

References

1. 
   

"Medical Dictionary". Farlex and Partners. Retrieved 25 October 2015.

Berkovitz BKB; Holland GR; Moxham BJ (2009). Oral Anatomy, Histology and Embryology. Mosby/Elsevier. p. 7. ISBN 978-0-7234-3551-8.

Ross et al., p. 485

Ten Cate's Oral Histology, Nancy, Elsevier, pages 70-94

M. Staines, W. H. Robinson and J. A. A. Hood (1981). "Spherical indentation of tooth enamel". Journal of Materials Science. 16 (9): 2551–2556. doi:10.1007/bf01113595. S2CID 137704231.

Ten Cate's Oral Histology, Nanci, Elsevier, 2013, page 122

Ten Cate's Oral Histology, Nanci, Elsevier, pages 70-94

Johnson

Illustrated Dental Embryology, Histology, and Anatomy, Bath-BaloghFehrenbach, Elsevier, 2011, page 180

Bath-Balogh, Fehrenbach, p. 179

Johnson, Clarke. "Biology of the Human Dentition Archived 2015-10-30 at the Wayback Machine." Page accessed July 18, 2007.

Marshall GW Jr, Marshall SJ, Kinney JH, Balooch M.J. The dentin substrate: structure and properties related to bonding J Dent. 1997 Nov;25(6):441-58.

American Academy of Periodontology 2010 In-Service Exam, question A-38

14. Kumar, G. (15 Jul 2011). Orban's Oral Histology & Embryology (13th ed.). Elsevier India. p. 152. ISBN 9788131228197. Retrieved 1 December 2014.

Category:

• Tissues (biology)

 

 ^{https://en.wikipedia.org/wiki/Hard_tissue}

Boundaries

The impact of a meteorite or comet is today widely accepted as the main reason for the Cretaceous–Paleogene extinction event.

See also: Cretaceous–Paleogene extinction event

The lower boundary of the Cretaceous is currently undefined, and the Jurassic–Cretaceous boundary is currently the only system boundary to lack a defined Global Boundary Stratotype Section and Point (GSSP). Placing a GSSP for this boundary has been difficult because of the strong regionality of most biostratigraphic markers, and the lack of any chemostratigraphic events, such as isotope excursions (large sudden changes in ratios of isotopes) that could be used to define or correlate a boundary. Calpionellids, an enigmatic group of planktonic protists with urn-shaped calcitic tests briefly abundant during the latest Jurassic to earliest Cretaceous, have been suggested as the most promising candidates for fixing the Jurassic–Cretaceous boundary.^[7] In particular, the first appearance Calpionella alpina, coinciding with the base of the eponymous Alpina subzone, has been proposed as the definition of the base of the Cretaceous.^[8] The working definition for the boundary has often been placed as the first appearance of the ammonite Strambergella jacobi, formerly placed in the genus Berriasella, but its use as a stratigraphic indicator has been questioned, as its first appearance does not correlate with that of C. alpina.^[9] The boundary is officially considered by the International Commission on Stratigraphy to be approximately 145 million years ago,^[10] but other estimates have been proposed based on U-Pb geochronology, ranging as young as 140 million years ago.^[11][12]

The upper boundary of the Cretaceous is sharply defined, being placed at an iridium-rich layer found worldwide that is believed to be associated with the Chicxulub impact crater, with its boundaries circumscribing parts of the Yucatán Peninsula and extending into the Gulf of Mexico. This layer has been dated at 66.043 Mya.^[13]

At the end of the Cretaceous, the impact of a large body with the Earth may have been the punctuation mark at the end of a progressive decline in biodiversity during the Maastrichtian age. The result was the extinction of three-quarters of Earth's plant and animal species. The impact created the sharp break known as the K–Pg boundary (formerly known as the K–T boundary). Earth's biodiversity required substantial time to recover from this event, despite the probable existence of an abundance of vacant ecological niches.^[14]

Despite the severity of the K-Pg extinction event, there were significant variations in the rate of extinction between and within different clades. Species that depended on photosynthesis declined or became extinct as atmospheric particles blocked solar energy. As is the case today, photosynthesizing organisms, such as phytoplankton and land plants, formed the primary part of the food chain in the late Cretaceous, and all else that depended on them suffered, as well. Herbivorous animals, which depended on plants and plankton as their food, died out as their food sources became scarce; consequently, the top predators, such as Tyrannosaurus rex, also perished.^[15] Yet only three major groups of tetrapods disappeared completely; the nonavian dinosaurs, the plesiosaurs and the pterosaurs. The other Cretaceous groups that did not survive into the Cenozoic Era — the ichthyosaurs, last remaining temnospondyls (Koolasuchus), and nonmammalian cynodonts (Tritylodontidae)  —  were already extinct millions of years before the event occurred.^{[citation needed]}

Coccolithophorids and molluscs, including ammonites, rudists, freshwater snails, and mussels, as well as organisms whose food chain included these shell builders, became extinct or suffered heavy losses. For example, ammonites are thought to have been the principal food of mosasaurs, a group of giant marine lizards related to snakes that became extinct at the boundary.^[16]

Omnivores, insectivores, and carrion-eaters survived the extinction event, perhaps because of the increased availability of their food sources. At the end of the Cretaceous, there seem to have been no purely herbivorous or carnivorous mammals. Mammals and birds that survived the extinction fed on insects, larvae, worms, and snails, which in turn fed on dead plant and animal matter. Scientists theorise that these organisms survived the collapse of plant-based food chains because they fed on detritus.^[17][14][18]

In stream communities, few groups of animals became extinct. Stream communities rely less on food from living plants and more on detritus that washes in from land. This particular ecological niche buffered them from extinction.^[19] Similar, but more complex patterns have been found in the oceans. Extinction was more severe among animals living in the water column than among animals living on or in the seafloor. Animals in the water column are almost entirely dependent on primary production from living phytoplankton, while animals living on or in the ocean floor feed on detritus or can switch to detritus feeding.^[14]

The largest air-breathing survivors of the event, crocodilians and champsosaurs, were semiaquatic and had access to detritus. Modern crocodilians can live as scavengers and can survive for months without food and go into hibernation when conditions are unfavorable, and their young are small, grow slowly, and feed largely on invertebrates and dead organisms or fragments of organisms for their first few years. These characteristics have been linked to crocodilian survival at the end of the Cretaceous.^[17]

Geologic formations

Drawing of fossil jaws of Mosasaurus hoffmanni, from the Maastrichtian of Dutch Limburg, by Dutch geologist Pieter Harting (1866)

Scipionyx, a theropod dinosaur from the Early Cretaceous of Italy

The high sea level and warm climate of the Cretaceous meant large areas of the continents were covered by warm, shallow seas, providing habitat for many marine organisms. The Cretaceous was named for the extensive chalk deposits of this age in Europe, but in many parts of the world, the deposits from the Cretaceous are of marine limestone, a rock type that is formed under warm, shallow marine conditions. Due to the high sea level, there was extensive space for such sedimentation. Because of the relatively young age and great thickness of the system, Cretaceous rocks are evident in many areas worldwide.

Chalk is a rock type characteristic for (but not restricted to) the Cretaceous. It consists of coccoliths, microscopically small calcite skeletons of coccolithophores, a type of algae that prospered in the Cretaceous seas.

Stagnation of deep sea currents in middle Cretaceous times caused anoxic conditions in the sea water leaving the deposited organic matter undecomposed. Half of the world's petroleum reserves were laid down at this time in the anoxic conditions of what would become the Persian Gulf and the Gulf of Mexico. In many places around the world, dark anoxic shales were formed during this interval,^[20] such as the Mancos Shale of western North America.^[21] These shales are an important source rock for oil and gas, for example in the subsurface of the North Sea.

Europe

See also: Category:Cretaceous System of Europe

In northwestern Europe, chalk deposits from the Upper Cretaceous are characteristic for the Chalk Group, which forms the white cliffs of Dover on the south coast of England and similar cliffs on the French Normandian coast. The group is found in England, northern France, the low countries, northern Germany, Denmark and in the subsurface of the southern part of the North Sea. Chalk is not easily consolidated and the Chalk Group still consists of loose sediments in many places. The group also has other limestones and arenites. Among the fossils it contains are sea urchins, belemnites, ammonites and sea reptiles such as Mosasaurus.

In southern Europe, the Cretaceous is usually a marine system consisting of competent limestone beds or incompetent marls. Because the Alpine mountain chains did not yet exist in the Cretaceous, these deposits formed on the southern edge of the European continental shelf, at the margin of the Tethys Ocean.

North America

See also: Category:Cretaceous System of North America

Map of North America During the Late Cretaceous

During the Cretaceous, the present North American continent was isolated from the other continents. In the Jurassic, the North Atlantic already opened, leaving a proto-ocean between Europe and North America. From north to south across the continent, the Western Interior Seaway started forming. This inland sea separated the elevated areas of Laramidia in the west and Appalachia in the east. Three dinosaur clades found in Laramidia (troodontids, therizinosaurids and oviraptorosaurs) are absent from Appalachia from the Coniacian through the Maastrichtian.^[22]

 ^{https://en.wikipedia.org/wiki/Cretaceous}

Berriasian
~145.0 – 139.8 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Chronology
−140 — – −130 — – −120 — – −110 — – −100 — – −90 — – −80 — – −70 — – M e s o z o i c C Z J C r e t a c e o u s P g L J E a r l y L a t e P C Tithonian Berriasian Valanginian Hauterivian Barremian Aptian Albian Cenoman. Turonian Coniacian Santonian Campanian Maastricht. Danian       ← K-Pg mass extinction Subdivision of the Cretaceous according to the ICS, as of 2022.[1] Vertical axis scale: millions of years ago.
Etymology
Name formality	Formal
Usage information
Celestial body	Earth
Regional usage	Global (ICS)
Time scale(s) used	ICS Time Scale
Definition
Chronological unit	Age
Stratigraphic unit	Stage
Time span formality	Formal
Lower boundary definition	Undefined
Lower boundary definition candidates	Magnetic—base of Chron M18r Base of Calpionellid zone B FAD of Ammonite Berriasella jacobi
Lower boundary GSSP candidate section(s)	None
Upper boundary definition	Undefined
Upper boundary definition candidates	FAD of the Calpionellid Calpionellites darderi
Upper boundary GSSP candidate section(s)	Montbrun-les-Bains, Drôme, France Cañada Luenga, Betic Cordillera, Spain

In the geological timescale, the Berriasian is an age/stage of the Early/Lower Cretaceous. It is the oldest subdivision in the entire Cretaceous. It has been taken to span the time between 145.0 ± 4.0 Ma and 139.8 ± 3.0 Ma (million years ago). The Berriasian succeeds the Tithonian (part of the Jurassic) and precedes the Valanginian. 

https://en.wikipedia.org/wiki/Berriasian

Coniacian
89.8 ± 0.3 – 86.3 ± 0.5 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Chronology
−140 — – −130 — – −120 — – −110 — – −100 — – −90 — – −80 — – −70 — – M e s o z o i c C Z J C r e t a c e o u s P g L J E a r l y L a t e P C Tithonian Berriasian Valanginian Hauterivian Barremian Aptian Albian Cenoman. Turonian Coniacian Santonian Campanian Maastricht. Danian       ← K-Pg mass extinction Subdivision of the Cretaceous according to the ICS, as of 2022.[1] Vertical axis scale: millions of years ago.
Etymology
Name formality	Formal
Usage information
Celestial body	Earth
Regional usage	Global (ICS)
Time scale(s) used	ICS Time Scale
Definition
Chronological unit	Age
Stratigraphic unit	Stage
Time span formality	Formal
Lower boundary definition	FAD of the Inoceramid Bivalve Cremnoceramus deformis erectus
Lower boundary GSSP	Salzgitter-Salder quarry, Germany 52.1243°N 10.3295°E
Lower GSSP ratified	May 2021
Upper boundary definition	FAD of the Inoceramid Bivalve Cladoceramus undulatoplicatus
Upper boundary GSSP	Olazagutia, Spain 42.8668°N 2.1968°W
Upper GSSP ratified	January 2013[2]

The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series and spans the time between 89.8 ± 1 Ma and 86.3 ± 0.7 Ma (million years ago). The Coniacian is preceded by the Turonian and followed by the Santonian.^[3] 

https://en.wikipedia.org/wiki/Coniacian

Albian
~113.0 – 100.5 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Chronology
−140 — – −130 — – −120 — – −110 — – −100 — – −90 — – −80 — – −70 — – M e s o z o i c C Z J C r e t a c e o u s P g L J E a r l y L a t e P C Tithonian Berriasian Valanginian Hauterivian Barremian Aptian Albian Cenoman. Turonian Coniacian Santonian Campanian Maastricht. Danian       ← K-Pg mass extinction Subdivision of the Cretaceous according to the ICS, as of 2022.[1] Vertical axis scale: millions of years ago.
Etymology
Name formality	Formal
Usage information
Celestial body	Earth
Regional usage	Global (ICS)
Time scale(s) used	ICS Time Scale
Definition
Chronological unit	Age
Stratigraphic unit	Stage
Time span formality	Formal
Lower boundary definition	FAD of the Planktonic Foraminifer Microhedbergella renilaevis
Lower boundary GSSP	Col de Pré-Guittard section, Arnayon, Drôme, France 44.4964°N 5.3114°E
Lower GSSP ratified	April 2016[2]
Upper boundary definition	FAD of the Planktonic Foraminifer Rotalipora globotruncanoides
Upper boundary GSSP	Mont Risoux, Hautes-Alpes, France 44.3925°N 5.5119°E
Upper GSSP ratified	2002[3]

The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous Epoch/Series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± 0.9 Ma (million years ago). The Albian is preceded by the Aptian and followed by the Cenomanian.^[4] 

https://en.wikipedia.org/wiki/Albian

The Maastrichtian ( /mɑːˈstrɪktiən/) is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from 72.1 to 66 million years ago. The Maastrichtian was preceded by the Campanian and succeeded by the Danian (part of the Paleogene and Paleocene).^[3]

The Cretaceous–Paleogene extinction event (formerly known as the Cretaceous–Tertiary extinction event)^[a] occurred at the end of this age.^[3] In this mass extinction, many commonly recognized groups such as non-avian dinosaurs, plesiosaurs and mosasaurs, as well as many other lesser-known groups, died out. The cause of the extinction is most commonly linked to an asteroid about 10 to 15 kilometres (6.2 to 9.3 mi) wide^[4][5] colliding with Earth, ending the Cretaceous. 

https://en.wikipedia.org/wiki/Maastrichtian

Spitidiscus

• Article
• Talk

• Read
• Edit
• View history

Tools

• 
  
• 
  
• 
  
• 
  
• 
  
• 
  
• 
  
• 
  

• 
  
• 
  

• 
  

From Wikipedia, the free encyclopedia

Spitidiscus Temporal range: Hauterivian-Barremian ~130–125 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Fossil shell of Spitidiscus species from Alpes-de-Haute-Provence, on display at Galerie de paléontologie et d'anatomie comparée in Paris
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	†Ammonoidea
Order:	†Ammonitida
Family:	†Holcodiscidae
Genus:	†Spitidiscus Kilian, 1910

Spitidiscus seunesi (Kilian) Barremian, Brestak, Cr1 426X1 (Coll. St. Breskovski) at the Sofia University Museum of Paleontology and Historical Geology

Spitidiscus is a genus of ammonites placed in the family Holcodiscidae.^[1][2]

Species

List of species within Spitidiscus:^[3]

• Spitidiscus hugii^{[citation needed]}
• Spitidiscus kilapiae Rawson and Aguirre-Urreta, 2012 - Argentina
• Spitidiscus oregonensis Imlay, 1960 - Oregon
• Spitidiscus riccardii Leanza, and Wiedmann, 1992 - Argentina
• Spitidiscus rotulia - England^{[citation needed]}
• Spitidiscus simitiensis Haas, 1960 - Colombia
• Spitidiscus vandeckii (d'Orbigny, 1847)

Description

Member species have a rather evolute shell in which the whorl section is more or less circular, venter broadly rounded and dorsum fairly deeply impressed. Close, fine low, single or rarely branching ribs are interspersed by frequent straight or slightly sinuous, moderately deep but wide constrictions. The type species S. rotulia is from the Hauterivian of England.^{[citation needed]}

Biostratigraphic significance

The first appearance of the species Spitidiscus hugii or Spitidiscus vandeckii are proposed to be the marker for the beginning of the Barremian.^[4]

Distribution

Spitidiscus has been found in:^[3]

• Agrio Formation, Argentina
• Magdalena Valley, Simití and Cáqueza, Colombia
• Kaliste Formation, Czech Republic
• France
• Gagra, Georgia, Caucasus
• Maiolica Formation, Italy
• Subbetics, Spain
• Foggy Creek, Oregon
• Bulgaria^{[citation needed]}
• Portugal^{[citation needed]}
• Russia^{[citation needed]}
• Morocco^{[citation needed]}
• Mexico^{[citation needed]}

References

1. 
   

Wright, C. W. with Callomon, J.H. and Howarth, M.K. (1996), Mollusca 4 Revised , Cretaceous Ammonoidea, vol. 4, in Treatise on Invertebrate Paleontology, Part L (Roger L. Kaesler et el. eds.), Boulder, Colorado: The Geological Society of America & Lawrence, Kansas: University of Kansas Press, at 69.

"Spitidiscus". Sepkoski's Online Genus Database – Cephalopoda.

Spitidiscus at Fossilworks.org

4. "GSSP Table - Mesozoic Era". Geologic Time Scale Foundation. Retrieved 15 January 2014.

Bibliography

• "Spidiscus". Paleobiology Database. Retrieved 30 December 2021.
• "Spidiscus". Encyclopedia of Life (EOL). Retrieved 30 December 2021.
• W.J. Arkell et al., (1957). Mesozoic Ammonoidea in Treatise on Invertebrate Paleontology, Part L, Ammonoidea. Geological Society of America and Univ Kansas Press.

Taxon identifiers	Wikidata: Q12267669 CoL: 7LFZ Fossilworks: 15660 GBIF: 4627556 IRMNG: 1379364

This Ammonitina-related article is a stub. You can help Wikipedia by expanding it.

Categories:

• Desmoceratoidea
• Ammonitida genera
• Index fossils
• Cretaceous ammonites
• Barremian life
• Hauterivian life
• Ammonites of Europe
• Fossils of the Czech Republic
• Cretaceous France
• Fossils of France
• Fossils of Georgia (country)
• Cretaceous Italy
• Fossils of Italy
• Cretaceous Spain
• Fossils of Spain
• Ammonites of North America
• Paleontology in Oregon
• Fossils of the United States
• Ammonites of South America
• Cretaceous Argentina
• Fossils of Argentina
• Cretaceous Colombia
• Fossils of Colombia
• Fossil taxa described in 1910
• Ammonitina stubs

 

 https://en.wikipedia.org/wiki/Spitidiscus

 

International Commission on Stratigraphy

Abbreviation	ICS
Formation	1974
Type	INGO
Region served	Worldwide
Official language	English, French
Parent organization	International Union of Geological Sciences (IUGS)
Website	ICS Official website

The International Commission on Stratigraphy (ICS), sometimes unofficially referred to as the "International Stratigraphic Commission", is a daughter or major subcommittee grade scientific daughter organization that concerns itself with stratigraphical, geological, and geochronological matters on a global scale.

It is the largest subordinate body of the International Union of Geological Sciences (IUGS). The ICS is essentially a permanent working subcommittee, which meets far more regularly than the quadrennial meetings scheduled by the IUGS, when it meets as a congress or membership of the whole. 

https://en.wikipedia.org/wiki/International_Commission_on_Stratigraphy

Cladoceramus Temporal range: Late Turonian-Santonian ~89.8–83.6 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Order:	Pteriida
Family:	†Inoceramidae
Genus:	†Cladoceramus Seitz 1961
Species
C. undulatoplicatus Roemer 1852

Cladoceramus is an extinct genus of fossil marine pteriomorphian bivalves that superficially resembled the related winged pearly oysters of the extant genus Pteria. They lived in the Santonian stage of the Late Cretaceous. 

https://en.wikipedia.org/wiki/Cladoceramus

Pachydiscus Temporal range: Late Cretaceous-Early Paleocene, Upper Cretaceous–Danian PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	†Ammonoidea
Order:	†Ammonitida
Family:	†Pachydiscidae
Genus:	†Pachydiscus Zittel, 1884
Synonyms
Parapachydiscus

Pachydiscus is an extinct genus of ammonite from the Late Cretaceous and Early Paleocene with a worldwide distribution, and type for the desmoceratacean family Pachydiscidae. The genus' type species is P. neubergicus. Altogether some 28 species have been described.

The shell of Pachydiscus is compressed and high-whorled, with an oval or flat sided section. Ribs tend to be differentiated into short umbilical and separate ventro-lateral sets, with a smooth area between. Some Hungarian specimens of this genus reached 40 cm (16 in) in diameter.^[1]

Pachydiscus includes two subgenera, P. (Pachysiscus) from the Campanian in which the ribs persist, and P. (Neodesmoceras) from the Maastrichtian in which ribs disappear early, leaving an almost smooth shell. 

https://en.wikipedia.org/wiki/Pachydiscus

Chemostratigraphy, or chemical stratigraphy, is the study of the chemical variations within sedimentary sequences to determine stratigraphic relationships. The field is relatively young, having only come into common usage in the early 1980s, but the basic idea of chemostratigraphy is nearly as old as stratigraphy itself: distinct chemical signatures can be as useful as distinct fossil assemblages or distinct lithographies in establishing stratigraphic relationships between different rock layers. 

https://en.wikipedia.org/wiki/Chemostratigraphy

The 'golden spike' (bronze disk in the lower section of the image) or 'type section' of the Global Boundary Stratotype Section and Point (GSSP) for the base of Ediacaran period (Ediacara, South Australia)

The 'golden spike' marking the Ediacaran GSSP

A Global Boundary Stratotype Section and Point (GSSP) is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundary of a stage on the geologic time scale. The effort to define GSSPs is conducted by the International Commission on Stratigraphy, a part of the International Union of Geological Sciences. Most, but not all, GSSPs are based on paleontological changes. Hence GSSPs are usually described in terms of transitions between different faunal stages, though far more faunal stages have been described than GSSPs. The GSSP definition effort commenced in 1977. As of 2022, 78 of the 101 stages that need a GSSP have a ratified GSSP.^[1]

https://en.wikipedia.org/wiki/Global_Boundary_Stratotype_Section_and_Point

Rules

A geologic section has to fulfill a set of criteria to be adapted as a GSSP by the ICS. The following list summarizes the criteria:^[2][3]

• A GSSP has to define the lower boundary of a geologic stage.
• The lower boundary has to be defined using a primary marker (usually first appearance datum of a fossil species).
  • There should also be secondary markers (other fossils, chemical, geomagnetic reversal).
  • The horizon in which the marker appears should have minerals that can be radiometrically dated.
  • The marker has to have regional and global correlation in outcrops of the same age
  • The marker should be independent of facies.
• The outcrop has to have an adequate thickness
• Sedimentation has to be continuous without any changes in facies
• The outcrop should be unaffected by tectonic and sedimentary movements, and metamorphism
• The outcrop has to be accessible to research and free to access.
  • This includes that the outcrop has to be located where it can be visited quickly (International airport and good roads), has to be kept in good condition (Ideally a national reserve), in accessible terrain, extensive enough to allow repeated sampling and open to researchers of all nationalities.

 https://en.wikipedia.org/wiki/Global_Boundary_Stratotype_Section_and_Point