Aminostratigraphical test of the East European Mammal Zonation for the late Neogene and Quaternary

An aminostratigraphical study was undertaken to provide an independent test of the veracity of the East European Mammal zonation. This important biostratigraphical scheme was originally defined from reference sites in the Azov/Black Sea region of southern Russia, but is now widely used to correlate late Neogene and Quaternary sediments across much of Europe and western Asia. As well as yielding a series of mammal assemblages, these reference sites, which range in age from the late Pliocene (Piacenzian ca. 3.0 Ma) to Late Pleistocene (0.1 Ma), also contain calcitic opercula of two genera (Bithynia and Parafossarulus) of freshwater gastropod snails that are suitable for amino acid dating. The intra-crystalline protein decomposition (IcPD) of four amino acids (aspartic acid, alanine, valine, and glutamic acid) was analysed from the opercula of these two genera, which showed similar patterns of protein degradation, allowing both to be used for aminostratigraphy. The IcPD data are consistent with the relative ages inferred from the mammal biostratigraphy and also with stratigraphical hiatuses interpreted from the fossil record. The temporal resolution provided by IcPD data from opercula is amino acid dependent, and declines in samples older than similar to 2 Ma. The high variability of IcPD between opercula samples at some sites suggests reworking. Anomalously high levels of IcPD in samples from the Early Pleistocene site of Tizdar may be due to geothermal heating from local mud volcanism. This study provides the first large-scale application of IcPD-based aminostratigraphy for the Quaternary of continental Europe, and highlights its importance in testing regional stratigraphic schemes for the Late Pliocene and the Pleistocene. (C) 2020 Elsevier Ltd. All rights reserved.