Reconstruction of paleoclimatic facets of sedimentation in Sevastopol Bay based on geochemical data

Abstract

Data on the abundance of petrogenic and trace elements (including rare earth elements) in the Quaternary deposits of Sevastopol Bay at the pre-technogenic stage of its development were obtained. Anomalies in the enrichment with Ag, Au, Hg, Pb and elevated levels of Cu, Zn, Cd, Sn, Sb in some layers were discovered. These features are apparently due to sulfide mineralization in the denudation area and the emergence of specific geochemical barriers (hydrodynamic and, possibly, saline ones) in the periods of changes in the paleogeographic environment. The ratios of the contents of elements sensitive to the change in the weathering type made it possible to establish the climate characteristics in the source area. During the accumulation of the liman deposits, relative warming and humidization took place, with the boundary strata of this period evidencing drier and colder conditions at the very beginning and completion of the deposit formation. The marine stage begins with warming (the lack of samples in the lower and middle parts does not allow us to trace further the prevailing conditions), but cooling and aridization are observed later on. These constructions fit into the general regional picture of climate change in the southwestern Crimea in the interval of 9.5–3.0thousand years ago.