TAPHONOMIC ANALYSIS OF THE EARLY CRETACEOUS FISHES FROM THE TURGA LAGERSTӒTTE (EASTERN TRANSBAIKALIA)
V.D. Efremenko, P.G. Borodin, I.N. Kosenko
Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: Jehol Biota, freshwater fishes, taphonomy, paleoenvironments
Abstract
Based on the differences of the fishes taphonomic states and the orictocenoses Turga paleolake burial features that led to the lagerstatten formation were reconstructed. The main factors that led to a high preservation state of the fossil fishes and invertebrates were the absence of hydrodynamic influence, oxygen deficiency, and water alkalinity. Important factor of the preservation was absence of prolonged postmortem flotation. Low water temperatures prevented postmortem floatation during the cold season, while elevated pH prevented it during warm season when temperatures was favorable for this. Bedding planes with shell pavements of clam shrimps Eosestheria middendorfii deposited during summer time and contained small-sized fishes. Larger fishes were buried during autumn and winter seasons.
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