Geochemical indicators of paleoclimatic changes in the Cenozoic deposits of the Lower Aldan Basin

Major and trace element composition of the Upper Cenozoic deposits of the Chuya section (the lower reaches of the Aldan River, Central Yakutia) made up of the Middle Miocene and Neopleistocene sediments was studied as indicator of paleoclimatic conditions. It was established that primary sediments were precipitated under moderately humid conditions in the Middle Miocene and under subarid climatic conditions at relatively high sedimentation rates in the Neopleistocene. Close contents of trace elements in all lithologies suggest that the source area remained constant. Variation trends of ICV index indicate an increasing role of fluvioglacial accumulation during formation of Pleistocene beds. It was determined that the Neopleistocene is marked by a sharp change in sedimentation conditions.