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Early Triassic
The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic, which is a unit in chronostratigraphy. The Early Triassic is the oldest epoch of the Mesozoic Era and is divided into the Induan and Olenekian ages.
The Lower Triassic series is coeval with the Scythian stage, which is today not included in the official timescales but can be found in older literature. In Europe, most of the Lower Triassic is composed of Buntsandstein, a lithostratigraphic unit of continental red beds.
==Early Triassic life==
The Permian-Triassic extinction event spawned the Triassic period. The massive extinctions that ended the Permian period and Paleozoic era caused extreme hardships for the surviving species. Many types of corals, brachiopods, molluscs, echinoderms, and other invertebrates had completely disappeared. The most common Early Triassic hard-shelled marine invertebrates were bivalves, gastropods, ammonites, echinoids, and a few articulate brachiopods. The most common land animal was the small herbivorous synapsid ''Lystrosaurus''.
Early Triassic faunas lacked biodiversity and were relatively homogenous throughout the epoch due to the effects of the extinction, ecological recovery on land took 30M years. The climate during the Early Triassic epoch (especially in the interior of the supercontinent Pangaea) was generally arid, rainless and dry and deserts were widespread however the poles possessed a temperate climate. The relatively hot climate of the Early Triassic may have been caused by widespread volcanic eruptions which accelerated the rate of global warming and possibly caused the Permian Triassic extinction event.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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