Triassic

Article By:

Manspeizer, Warren Department of Geological Sciences, Faculty of Arts and Sciences, Rutgers University, New Jersey.

Last reviewed:December 2019

DOI:https://doi.org/10.1036/1097-8542.708500

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• Triassic, published June 2014:Download PDF Get Adobe Acrobat Reader

The oldest period of the Mesozoic Era. The Triassic encompasses an interval from about 252 to 201 million years ago (MYA) [Fig. 1]. It was named in 1848 by F. A. von Alberti for the threefold division of rocks at its type locality in central Germany, where continental redbeds and evaporites of the older Buntsandstein and younger Keuper formations are separated by marine limestones and marls of the Muschelkalk formation. These carbonates were laid down in a shallow tongue of the Tethys seaway that extended from the Himalayas through the Middle East to the Pyrenees, where more than 10,000 ft (3000 m) of carbonate were deposited. The German section was an unfortunate choice because it is atypical of other Triassic sections and carries a sparsely preserved fossil record. It was subsequently replaced by a marine carbonate sequence in the Alps as the standard for global Triassic reference and correlation. The North American standard marine section is in the western Cordilleras of British Columbia and the Sverdrup Basin of the Arctic. See also: Mesozoic

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