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The Cambrian explosion (also known as Cambrian radiation [1] or Cambrian diversification) is an interval of time beginning approximately in the Cambrian period of the early Paleozoic, when a sudden radiation of complex life occurred and practically all major animal phyla started appearing in the fossil record.
Oklahoma was a terrestrial environment for most of the ensuing Mesozoic era. [3] The Late Triassic Dockum Group of western Oklahoma preserved remains of archosaurs and temnospondyls, although its fossil record is restricted to a narrow region of the panhandle and is far sparser than the equivalent records in Texas, New Mexico, and Arizona. [98]
The Roosevelt Gabbros were originally intruded in the early Cambrian between the Glen Mountain Layered Complex and the Mount Scott Granite as the southern Oklahoma aulacogen was being formed. [1] The formation of this aulacogen resulted from rifting that took place as the Neoproterozoic supercontinent Pannotia was breaking apart. [2]
Fossil of the Cambrian-Middle Devonian trilobite Cheirurus †Cheirurus †Chonetes †Chonetes mesoloba †Cladochonus †Cleiothyridina †Cleiothyridina orbicularis †Clepsydrops; Cliona †Colobomycter – type locality for genus †Colobomycter pholeter – type locality for species †Composita †Composita mexicana †Composita rotunda
The Great Ordovician Biodiversification Event (GOBE) was an evolutionary radiation of animal life throughout [1] the Ordovician period, 40 million years after the Cambrian explosion, [2] whereby the distinctive Cambrian fauna fizzled out to be replaced with a Paleozoic fauna rich in suspension feeder and pelagic animals.
Most scientists agree that complex life likely formed during the Ediacaran Period some 600 million years ago—right on the cusp of the well-known Cambrian Explosion.
The Cambrian (/ ˈ k æ m b r i. ə n, ˈ k eɪ m-/ KAM-bree-ən, KAYM-) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. [5] The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordovician Period 486.85 Ma.
The geology of Oklahoma is characterized by Carboniferous rocks in the east, Permian rocks in the center and towards the west, and a cover of Tertiary deposits in the panhandle to the west. The panhandle of Oklahoma is also noted for its Jurassic rocks as well.