The Late Pleistocene palaeoenvironmental evolution in Northern Eurasia through the prism of the mollusc shell-based ESR dating evidence

Abstract

Long-term investigations devoted mostly to the Eurasian Arctic sedimentary deposits have provided dated climatic sequence within the Late Pleistocene period. Most of the dates (ca. 315) were obtained by electron spin resonance (ESR) method on marine mollusc remains taken directly from transgressive marine sedimentary deposits. Here, it is shown that the climatic signature revealed in the studied sedimentary sequences can be compared by proxy- and chronologic correlation with the climatic signals recorded in different parts of the continent from deposits of marine, freshwater, and terrestrial origin. The resulting climate-chronostratigraphic record allow the last interglacial to be placed approximately between 145–140 ka and 70 ka with concentration of overwhelming majority of the warm climate-related dates (ca. 82%) in the second half of Marine Isotope Stage (MIS) 5 in the time range between 110 and 70 ka. This evidence coincides with integrative multidisciplinary results derived from the south-eastern coast of the Gulf of Finland. They show unambiguously that the second half of the MIS 5 sequence, at least between ca. 94 ka and 71 ka, reflects the fully interglacial character of the studied deposits. The climate-chronostratigraphic record within MIS 3 displays a sequence of three successive palaeoenvironmental events (59.0–52.0 ka, 47.5–40.0 ka and 32.4–24.8 ka), which are interpreted as the consequence of large-scale climate amelioration during which marine sedimentation occurred on palaeo-shelves what is now dry land. The consistency of the parallel comparative dating results obtained in this study by different methods, both the numerical and relative, exemplify the potential of palaeodosimetric dating methods mainly used in this study — mollusc shell-based electron spin resonance (ESR) and feldspar-based infrared optically stimulated luminescence (IR-OSL) — to chronologically organize the sequence of the Late Pleistocene palaeoenvironmental events, and to improve understanding of the palaeoenvironmental evolution during this period.