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The AAPG/Datapages Combined Publications Database

CSPG Special Publications


Permian Triassic Systems and Their Mutual Boundary — Memoir 2, 1973
Pages 481-492

Tetrapods and the Permian-Triassic Transition

E. H. Colbert


The transition between the Permian and the Triassic Periods would seem to include one of the great faunal breaks in geological history. There is abundant evidence for this, particularly among fossils collected from marine rocks in the Northern Hemisphere. A question arises, however, as to whether all faunal breaks between these two geological periods are as profound as some of them appear to be. This question is brought to the fore by the record of sediments and included terrestrial vertebrates, especially as they occur in certain parts of the Southern Hemisphere. In South Africa there is little sedimentary evidence to distinguish between the top of the Permian Daptocephalus Zone and the base of the Triassic Lystrosaurus Zone. Although there are many extinctions among terrestrial vertebrates at the end of the Permian Period, there are also important holdovers from that period into the Triassic. The Carboniferous, Permian and Triassic terrestrial sediments are characterized by the presence within them of labyrinthodont amphibians, primitive reptiles, and diverse mammal-like reptiles, which is in decided contrast to the Jurassic and Cretaceous terrestrial sediments, containing modern types of amphibians and reptiles, as well as the ubiquitous and dominant archosaurian reptiles. Thus there was a significant break in vertebrate life at the end of the Triassic Period, as well as at the close of the Permian Period.

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