Cretaceous Period - Revision history

71.134.32.159: /* Marine Fauna */

2011-04-20T21:26:22Z

Marine Fauna

← Older revision		Revision as of 21:26, 20 April 2011
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	Baculites, an ammonite genus with a straight shell, flourished in the seas along with reef-building rudist clams. The Hesperornithiformes were flightless, marine diving birds that swam like grebes. Globotruncanid Foraminifera and echinoderms such as sea urchins and starfish (sea stars) thrived. The first radiation of the diatoms (generally siliceous, rather than calcareous) in the oceans occurred during the Cretaceous; freshwater diatoms did not appear until the Miocene.[18] The Cretaceous was also an important interval in the evolution of bioerosion, the production of borings and scrapings in rocks, hardgrounds and shells (Taylor and Wilson, 2003).		Baculites, an ammonite genus with a straight shell, flourished in the seas along with reef-building rudist clams. The Hesperornithiformes were flightless, marine diving birds that swam like grebes. Globotruncanid Foraminifera and echinoderms such as sea urchins and starfish (sea stars) thrived. The first radiation of the diatoms (generally siliceous, rather than calcareous) in the oceans occurred during the Cretaceous; freshwater diatoms did not appear until the Miocene.[18] The Cretaceous was also an important interval in the evolution of bioerosion, the production of borings and scrapings in rocks, hardgrounds and shells (Taylor and Wilson, 2003).
			fart fart fatr moo

	==Extinction==		==Extinction==

71.134.32.159: /* Marine Fauna */

2011-04-20T21:24:03Z

Marine Fauna

← Older revision		Revision as of 21:24, 20 April 2011
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	----		----
	[[File:Asteroceras BW.jpg\|thumb\|right\|300px\|Asteroceras an Annomite example of marine Life from the period]]		[[File:Asteroceras BW.jpg\|thumb\|right\|300px\|Asteroceras an Annomite example of marine Life from the period]]
	In the seas, rays, modern sharks and teleosts became common. Marine reptiles included ichthyosaurs in the early and middle of the Cretaceous, becoming extinct during the late Cretaceous, plesiosaurs throughout the entire period, and mosasaurs appearing in the Late Cretaceous.		In the seas, rays, modern sharks and teleosts became common. Marine reptiles included ichthyosaurs in the early and middle of the Cretaceous, becoming extinct during the late Cretaceous, plesiosaurs throughout the entire period, and mosasaurs appearing in the Late Cretaceous.moo moo moo cow

	Baculites, an ammonite genus with a straight shell, flourished in the seas along with reef-building rudist clams. The Hesperornithiformes were flightless, marine diving birds that swam like grebes. Globotruncanid Foraminifera and echinoderms such as sea urchins and starfish (sea stars) thrived. The first radiation of the diatoms (generally siliceous, rather than calcareous) in the oceans occurred during the Cretaceous; freshwater diatoms did not appear until the Miocene.[18] The Cretaceous was also an important interval in the evolution of bioerosion, the production of borings and scrapings in rocks, hardgrounds and shells (Taylor and Wilson, 2003).		Baculites, an ammonite genus with a straight shell, flourished in the seas along with reef-building rudist clams. The Hesperornithiformes were flightless, marine diving birds that swam like grebes. Globotruncanid Foraminifera and echinoderms such as sea urchins and starfish (sea stars) thrived. The first radiation of the diatoms (generally siliceous, rather than calcareous) in the oceans occurred during the Cretaceous; freshwater diatoms did not appear until the Miocene.[18] The Cretaceous was also an important interval in the evolution of bioerosion, the production of borings and scrapings in rocks, hardgrounds and shells (Taylor and Wilson, 2003).

71.134.32.159: /* Revised Cause of Extinction */

2011-04-15T18:20:24Z

Revised Cause of Extinction

← Older revision		Revision as of 18:20, 15 April 2011
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	==Revised Cause of Extinction==		==Revised Cause of Extinction==

	It is now known that the [[Chicxulub Crater\|Chicxulub Impact]] was not made by an iridium rich asteroid as originally hypothesized, but the bulk of the [[Tkon Nanosphere]] that crashed into the [[Earth]] after it was critically damaged by the combined efforts of the [[USS Rosenante]] and the [[USS Boudicca]], who were forced to destroy it after it was captured and assimilated by the [[Borg Collective]] with the intention of being used to seed the [[Earth\|Earth's]] atmosphere with [[Borg]] [[Nanoprobe]]s, thereby assimilating the [[Human]] race in the past.		It is now known that the [[Chicxulub Crater\|Chicxulub Impact]] was not made by an iridium rich asteroid as originally hypothesized, but the bulk of the [[Tkon Nanosphere]] that crashed into the [[Earth]] after it was critically damaged by the combined efforts of the [[USS Rosenante]] and the [[USS Boudicca]], who were forced to destroy it after it was captured and assimilated by the [[Borg Collective]] with the intention of being used to seed the [[Earth\|Earth's]] atmosphere with [[Borg]] [[Nanoprobe]]s, thereby assimilating the [[Human]] race in the past.hngf

	[[Category: History]][[Category: Science]]		[[Category: History]][[Category: Science]]

Nicesociety: /* Revised Cause of Extinction */

2010-11-03T19:15:31Z

Revised Cause of Extinction

← Older revision		Revision as of 19:15, 3 November 2010
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	==Revised Cause of Extinction==		==Revised Cause of Extinction==

	It is now known that the [[Chicxulub Crater\|Chicxulub Impact]] was not made by an iridium rich asteroid as originally hypothesized, but the bulk of the [[Tkon Nanosphere]] that crashed into the [[Earth]] after it was critically damaged by the combined efforts of the [[USS Rosenante]] and the [[USS Boudicca]], who were forced to destroy it after it was captured and assimilated by the [[Borg Collective]] with the intention of being used to seed the [[Earth\|Earth's]] atmosphere with [[Borg]] [[Nanoprobe]]s, thereby assimilating the ~~human~~ race in the past.		It is now known that the [[Chicxulub Crater\|Chicxulub Impact]] was not made by an iridium rich asteroid as originally hypothesized, but the bulk of the [[Tkon Nanosphere]] that crashed into the [[Earth]] after it was critically damaged by the combined efforts of the [[USS Rosenante]] and the [[USS Boudicca]], who were forced to destroy it after it was captured and assimilated by the [[Borg Collective]] with the intention of being used to seed the [[Earth\|Earth's]] atmosphere with [[Borg]] [[Nanoprobe]]s, thereby assimilating the [[Human]] race in the past.

	[[Category: History]][[Category: Science]]		[[Category: History]][[Category: Science]]

Nicesociety: /* Extinction */

2010-11-03T19:14:57Z

Extinction

← Older revision		Revision as of 19:14, 3 November 2010
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	Baculites, an ammonite genus with a straight shell, flourished in the seas along with reef-building rudist clams. The Hesperornithiformes were flightless, marine diving birds that swam like grebes. Globotruncanid Foraminifera and echinoderms such as sea urchins and starfish (sea stars) thrived. The first radiation of the diatoms (generally siliceous, rather than calcareous) in the oceans occurred during the Cretaceous; freshwater diatoms did not appear until the Miocene.[18] The Cretaceous was also an important interval in the evolution of bioerosion, the production of borings and scrapings in rocks, hardgrounds and shells (Taylor and Wilson, 2003).		Baculites, an ammonite genus with a straight shell, flourished in the seas along with reef-building rudist clams. The Hesperornithiformes were flightless, marine diving birds that swam like grebes. Globotruncanid Foraminifera and echinoderms such as sea urchins and starfish (sea stars) thrived. The first radiation of the diatoms (generally siliceous, rather than calcareous) in the oceans occurred during the Cretaceous; freshwater diatoms did not appear until the Miocene.[18] The Cretaceous was also an important interval in the evolution of bioerosion, the production of borings and scrapings in rocks, hardgrounds and shells (Taylor and Wilson, 2003).

	=== Extinction===		==Extinction==

	There was a progressive decline in biodiversity during the Maastrichtian stage of the Cretaceous Period prior to the suggested ecological crisis induced by events at the [[K–T Boundary]]. Furthermore, biodiversity required a substantial amount of time to recover from the K-T event, despite the probable existence of an abundance of vacant ecological niches.		There was a progressive decline in biodiversity during the Maastrichtian stage of the Cretaceous Period prior to the suggested ecological crisis induced by events at the [[K–T Boundary]]. Furthermore, biodiversity required a substantial amount of time to recover from the K-T event, despite the probable existence of an abundance of vacant ecological niches.
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	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, it is thought that ammonites were the principal food of mosasaurs, a group of giant marine reptiles that became extinct at the boundary.		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, it is thought that ammonites were the principal food of mosasaurs, a group of giant marine reptiles that became extinct at the boundary.
	[[File:Tkon Nanosphere Impact.jpg\|thumb\|~~right~~\|400px\|The Impact of the Tkon Nanosphere that triggered the K-T Extinction event]]		[[File:Tkon Nanosphere Impact.jpg\|thumb\|left\|400px\|The Impact of the Tkon Nanosphere that triggered the K-T Extinction event]]
	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 which 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.		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 which 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.

Nicesociety: /* Marine Fauna */

2010-11-03T19:14:30Z

Marine Fauna

← Older revision		Revision as of 19:14, 3 November 2010
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	===Marine Fauna===		===Marine Fauna===
			----
	[[File:Asteroceras BW.jpg\|thumb\|right\|300px\|Asteroceras an Annomite example of marine Life from the period]]		[[File:Asteroceras BW.jpg\|thumb\|right\|300px\|Asteroceras an Annomite example of marine Life from the period]]
	In the seas, rays, modern sharks and teleosts became common. Marine reptiles included ichthyosaurs in the early and middle of the Cretaceous, becoming extinct during the late Cretaceous, plesiosaurs throughout the entire period, and mosasaurs appearing in the Late Cretaceous.		In the seas, rays, modern sharks and teleosts became common. Marine reptiles included ichthyosaurs in the early and middle of the Cretaceous, becoming extinct during the late Cretaceous, plesiosaurs throughout the entire period, and mosasaurs appearing in the Late Cretaceous.

Nicesociety: /* Terrestrial Fauna */

2010-11-03T19:14:21Z

Terrestrial Fauna

← Older revision		Revision as of 19:14, 3 November 2010
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	===Terrestrial Fauna===		===Terrestrial Fauna===
			----
	[[File:Tyrannosaurus BW.jpg\|thumb\|300px\|left\|Tyrannosaurus Rex, the pereminent Terrastrial Predator of the age]]		[[File:Tyrannosaurus BW.jpg\|thumb\|300px\|left\|Tyrannosaurus Rex, the pereminent Terrastrial Predator of the age]]
	On land, mammals were a small and still relatively minor component of the fauna. Early marsupial mammals evolved in the Early Cretaceous, with true placentals emerging in the Late Cretaceous period. The fauna was dominated by archosaurian reptiles, especially dinosaurs, which were at their most diverse stage. Pterosaurs were common in the early and middle Cretaceous, but as the Cretaceous proceeded they faced growing competition from the adaptive radiation of birds, and by the end of the period only two highly specialized families remained.		On land, mammals were a small and still relatively minor component of the fauna. Early marsupial mammals evolved in the Early Cretaceous, with true placentals emerging in the Late Cretaceous period. The fauna was dominated by archosaurian reptiles, especially dinosaurs, which were at their most diverse stage. Pterosaurs were common in the early and middle Cretaceous, but as the Cretaceous proceeded they faced growing competition from the adaptive radiation of birds, and by the end of the period only two highly specialized families remained.

Nicesociety: /* Life */

2010-11-03T19:14:08Z

Life

← Older revision		Revision as of 19:14, 3 November 2010
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	==Life==		==Life==
	===Plants===		===Plants===
	[[File:Flowers.gif\|thumb\|250px\|~~left~~\|An example of a flowering Angiosperms]]		[[File:Flowers.gif\|thumb\|250px\|right\|An example of a flowering Angiosperms]]

	Flowering plants (angiosperms) spread during this period, although they did not become predominant until the Campanian stage near the end of the epoch. Their evolution was aided by the appearance of bees; in fact angiosperms and insects are a good example of coevolution. The first representatives of many leafy trees, including figs, planes and magnolias, appeared in the Cretaceous. At the same time, some earlier Mesozoic gymnosperms like Conifers continued to thrive; pehuéns (Monkey Puzzle trees, Araucaria) and other conifers being notably plentiful and widespread, although other gymnosperm taxa like Bennettitales died out before the end of the period.		Flowering plants (angiosperms) spread during this period, although they did not become predominant until the Campanian stage near the end of the epoch. Their evolution was aided by the appearance of bees; in fact angiosperms and insects are a good example of coevolution. The first representatives of many leafy trees, including figs, planes and magnolias, appeared in the Cretaceous. At the same time, some earlier Mesozoic gymnosperms like Conifers continued to thrive; pehuéns (Monkey Puzzle trees, Araucaria) and other conifers being notably plentiful and widespread, although other gymnosperm taxa like Bennettitales died out before the end of the period.

	===Terrestrial Fauna===		===Terrestrial Fauna===
	[[File:Tyrannosaurus BW.jpg\|thumb\|300px\|~~right~~\|Tyrannosaurus Rex, the pereminent Terrastrial Predator of the age]]		[[File:Tyrannosaurus BW.jpg\|thumb\|300px\|left\|Tyrannosaurus Rex, the pereminent Terrastrial Predator of the age]]
	On land, mammals were a small and still relatively minor component of the fauna. Early marsupial mammals evolved in the Early Cretaceous, with true placentals emerging in the Late Cretaceous period. The fauna was dominated by archosaurian reptiles, especially dinosaurs, which were at their most diverse stage. Pterosaurs were common in the early and middle Cretaceous, but as the Cretaceous proceeded they faced growing competition from the adaptive radiation of birds, and by the end of the period only two highly specialized families remained.		On land, mammals were a small and still relatively minor component of the fauna. Early marsupial mammals evolved in the Early Cretaceous, with true placentals emerging in the Late Cretaceous period. The fauna was dominated by archosaurian reptiles, especially dinosaurs, which were at their most diverse stage. Pterosaurs were common in the early and middle Cretaceous, but as the Cretaceous proceeded they faced growing competition from the adaptive radiation of birds, and by the end of the period only two highly specialized families remained.

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	===Marine Fauna===		===Marine Fauna===
	[[File:Asteroceras BW.jpg\|thumb\|~~left~~\|300px\|Asteroceras an Annomite example of marine Life from the period]]		[[File:Asteroceras BW.jpg\|thumb\|right\|300px\|Asteroceras an Annomite example of marine Life from the period]]
	In the seas, rays, modern sharks and teleosts became common. Marine reptiles included ichthyosaurs in the early and middle of the Cretaceous, becoming extinct during the late Cretaceous, plesiosaurs throughout the entire period, and mosasaurs appearing in the Late Cretaceous.		In the seas, rays, modern sharks and teleosts became common. Marine reptiles included ichthyosaurs in the early and middle of the Cretaceous, becoming extinct during the late Cretaceous, plesiosaurs throughout the entire period, and mosasaurs appearing in the Late Cretaceous.

Nicesociety: /* Rock formations */

2010-11-03T19:13:37Z

Rock formations

← Older revision		Revision as of 19:13, 3 November 2010
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	===Rock formations===		===Rock formations===
			----
	The high eustatic sea level and warm climate of the Cretaceous meant a large area of the continents was covered by warm shallow seas. The Cretaceous was named for the extensive chalk deposits of this age in Europe, but in many parts of the world, the Cretaceous system consists for a major part of marine limestone, a rock type that is formed under warm, shallow marine circumstances. Due to the high sea level there was extensive accommodation space for sedimentation so that thick deposits could form. Because of the relatively young age and great thickness of the system, Cretaceous rocks crop out in many areas worldwide.		The high eustatic sea level and warm climate of the Cretaceous meant a large area of the continents was covered by warm shallow seas. The Cretaceous was named for the extensive chalk deposits of this age in Europe, but in many parts of the world, the Cretaceous system consists for a major part of marine limestone, a rock type that is formed under warm, shallow marine circumstances. Due to the high sea level there was extensive accommodation space for sedimentation so that thick deposits could form. Because of the relatively young age and great thickness of the system, Cretaceous rocks crop out in many areas worldwide.

Nicesociety: /* Stratigraphic Subdivisions */

2010-11-03T19:13:30Z

Stratigraphic Subdivisions

← Older revision		Revision as of 19:13, 3 November 2010
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	===Stratigraphic Subdivisions===		===Stratigraphic Subdivisions===
			----
	[[File:Exposed KT boundary.jpg\|thumb\|350px\|right\|A bluff in South Dakota, showing the Stratigraphic subdivisions and the K-T boundary clearly]]		[[File:Exposed KT boundary.jpg\|thumb\|350px\|right\|A bluff in South Dakota, showing the Stratigraphic subdivisions and the K-T boundary clearly]]
	The Cretaceous is divided into Early and Late Cretaceous epochs or Lower and Upper Cretaceous series. In older literature the Cretaceous is sometimes divided into three series: Neocomian (lower/early), Gallic (middle) and Senonian (upper/late). A subdivision in eleven stages, all origining from European stratigraphy, is now used worldwide. In many parts of the world, alternative local subdivisions are still in use.		The Cretaceous is divided into Early and Late Cretaceous epochs or Lower and Upper Cretaceous series. In older literature the Cretaceous is sometimes divided into three series: Neocomian (lower/early), Gallic (middle) and Senonian (upper/late). A subdivision in eleven stages, all origining from European stratigraphy, is now used worldwide. In many parts of the world, alternative local subdivisions are still in use.