Tetrapod Localities from the Triassic of the SE of European Russia
Earth-Science Reviews 60 (2002) 1–66 www.elsevier.com/locate/earscirev Tetrapod localities from the Triassic of the SE of European Russia Valentin P. Tverdokhlebova, Galina I. Tverdokhlebovaa, Mikhail V. Surkova,b, Michael J. Bentonb,* a Geological Institute of Saratov State University, Ulitsa Moskovskaya, 161, Saratov 410075, Russia b Department of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, UK Received 5 November 2001; accepted 22 March 2002 Abstract Fossil tetrapods (amphibians and reptiles) have been discovered at 206 localities in the Lower and Middle Triassic of the southern Urals area of European Russia. The first sites were found in the 1940s, and subsequent surveys, from the 1960s to the present day, have revealed many more. Broad-scale stratigraphic schemes have been published, but full documentation of the rich tetrapod faunas has not been presented before. The area of richest deposits covers some 900,000 km2 of territory between Samara on the River Volga in the NW, and Orenburg and Sakmara in the SW. Continental sedimentary deposits, consisting of mudstones, siltstones, sandstones, and conglomerates deposited by rivers flowing off the Ural Mountain chain, span much of the Lower and Middle Triassic (Induan, Olenekian, Anisian, Ladinian). The succession is divided into seven successive svitas, or assemblages: Kopanskaya (Induan), Staritskaya, Kzylsaiskaya, Gostevskaya, and Petropavlovskaya (all Olenekian), Donguz (Anisian), and Bukobay (Ladinian). This succession, comprising up to 3.5 km of fluvial and lacustrine sediments, documents major climatic changes. At the beginning of the Early Triassic, arid-zone facies were widely developed, aeolian, piedmont and proluvium. These were replaced by fluvial facies, with some features indicating aridity.
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