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Difino
| • | The Triassic is a geologic period that extends from about 245 to 202 Ma (million years ago). As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both start and end of the Triassic are marked by major extinction events. The extinction event that closed the Triassic period has recently been more accurately dated, but as with most older geologic periods, the rock beds that define the start and end are well identified, but the exact dates of the start and end of the period are uncertain by a few million years.
The characteristic sediments of the Triassic are red sandstones and evaporites, which suggest a warm dry climate. There is no evidence of glaciation; as far as can be determined, there was no land or ice caps near either pole. The supercontinent Pangaea was rifting during the Triassic but had not yet separated; the first marine sediments in the earliest rift, which separated New Jersey from Morocco, are Late Triassic in origin. Because of the limited shoreline of one super-continental mass, Triassic marine deposits are globally relatively rare, despite their prominence in Western Europe, where the Triassic was first studied. In North America, for example, marine deposits are limited to a few exposures in the West. Thus Triassic stratigraphy is mostly based on organisms living in lagoons and hypersaline environments, such as Estheria crustaceans.
During the Triassic both marine and continental life show an adaptative radiation, following the Permian-Triassic extinction. Corals of the hexacorallia group make their first appearance. The first flowering plants (Angiosperms) may have evolved during the Triassic, as did the first flying vertebrates, the pterosaurs.
Source: [wikipedia: triassic]
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mesozoic:by_geological_interval
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