First results of study of Lake Baunt bottom sediments (northern Transbaikalia)

Abstract

In March 2014, the Lake Baunt bottom sediments were drilled in the deepest part of the lake basin (33 m). The penetrated interval is 13.7 m thick, with the age of the base being evaluated at 28-30 ka. Lithological study of the penetrated sediments demonstrates the upper part of the section dominated by diatom ooze, whose concentration decreases gradually downward the section, up to the replacement of the ooze by silty clay. The obtained data on variations in petromagnetic parameters, concentration of biogenic silica, and sediment compaction indicate considerable variations of sedimentary environments during the Late Pleistocene and Holocene. Being compared with the previously reconstructed landscape and climate dynamics for the sedimentary succession of Lake Kotokel for this time interval, the above parameters reveal that the Lake Baunt bottom sediments reliably fix the regional paleoclimate signal. For the first time for lakes of the Baikal region, Gothenburg and Mono Lake magnetic excursions are identified in the paleomagnetic record of the Lake Baunt section.