Study of coal-bearing sediments in South Baikal as part of the field expedition on R/V “Papanin”, July 13–14, 2024

Field works were carried out within the State Assignments No. 0279-2021-0005 “Study of seasonal and long-term transformations of the state of water bodies, and watercourses in East Siberia in the context of climate change, geological environment and anthropogenic loads” (led by A.P. Fedotov ) and No. 0279-2021-0006 “Studies of functioning of hydrate, oil and gaseous hydrocarbon systems and associated microbial communities in Lake Baikal” (led by T.I. Zemskaya).

The purpose of the expedition work was to study underwater geological sections, including proto-Baikal sediments, which were formed more than 25 million years ago, when Lake Baikal and its surrounding mountains did not yet have their current shapes. Most likely, these sediments were formed before or immediately after the collision of the Indian plate with Eurasia, which caused the intensification of tectonic activity that boosted the formation of the Baikal Trench.

Frequent interlayering of coal-bearing layers with aqualtic sediments indicates that a large water body existed in this area, which was periodically shallow and refilled again. We are going to find out based on the selected samples:

• the direction of currents of the rivers that filled the water body;
• hydrochemical conditions in the water body;
• palaeoclimate of the studied period;
• duration of coal-bearing layers formation.

It may be possible to find in the selected samples ancestral forms of the modern biota of Lake Baikal.

Also during the field work, samples of gas emanating from the sediments were taken to study the gas genesis.