Early Pleistocene Pedosediments of the Lori Basin (Armenia): Genesis, Properties, and Paleogeographic Interpretation

摘要

Red-colored pedosediments were described in the sections of the Lori Basin in northern Armenia. The environmental conditions in the period of their formation have been reconstructed. The Early Pleistocene pedosediments in Yagdan and Kurtan-IV sections are available for study due to their conservation under the products of volcanic activity, which are dated earlier than 2 and 1.4 Ma, respectively. Prior to burial, the pedosediments were exposed to molten lava, which affected their composition and properties. We used the micromorphological method to study the pedosediments and determined the magnetic susceptibility, particle-size and total chemical composition, the content of carbon and nitrogen, and the biomorphs. Signs of the formation of the studied pedosediments in a humid warm (subtropical) climate were found, which corresponded to the results of earlier studies. Based on the combination of features, soil formations from the Yagdan section were assigned to Cambisols with Argic, Vitric, and Chromic qualifiers. Additional elements were input from the above layer of basalt lava to the sediments: copper, chromium, nickel, cobalt, and vanadium, which was reflected in an increase in the specific magnetic susceptibility and enabled us to specify the soil and sediments by geochemical coefficients. Pedosediments from Kurtan-IV section were characterized by Stagnic and Luvic features. They were also formed in a humid but cooler climate.