Expedition onboard RV “G. Titov”, July 01-10, 2019

The expedition within the program “Study of the Influence of Mud Volcanoes and Methane Seeps on the Biological Communities of the Abyssal Zone of Lake Baikal” and under the research contract was carried out onboard RV “G. Titov”, July 01-10, 2019.

The aim of the expedition was to obtain new high-resolution bathymetric data on the bottom surface in the northern basin and clarify the relief characteristics of hydrate-bearing structures previously discovered in the central basin. The fieldworks were necessary to determine the main and new patterns in the structure and development of the continental rift depression as well as to search for mud volcanoes and seeps for further studies of new hydrate-bearing areas. Moreover, new bathymetric data are necessary for compiling a high-resolution bathymetric map of the Lake Baikal floor, which can be the basis for an electronic model of the sedimentary fill of the lake.

Geophysical fieldworks onboard RV “G. Titov” were carried out together with researchers from Irkutsk National Research Technical University. Bathymetric survey of the floor was performed using a Konengsberg EM710S multibeam echosounder and Khuds profilograph. During the expedition, a detailed bathymetric survey was performed for a part of the bottom surface in the northern basin of Baikal near Chivyrkui Bay − Davsha Bay. The multibeam echosounder recorded 295 files with a total length of 1776.2 km. The total recorded area is approximately 1709 km2. The total volume of the recorded files is 3308.9 km2. The maximum depth was 892.74 m and the minimum – 18.49 m. The average coverage of multi-beam echosounder is 1735.69 m; the length of profilograph data was 1453.7 km; the number of traversers was 37; and the number of SGY files was 173.

The resolution of new data is twice higher than that of the 2009 survey using an ELAC SeaBeam 1050 multibeam echosounder (http://lin.irk.ru/multibeam/ru/). The primary processing and analysis of new data indicated the main characteristics of the bottom relief in the investigated areas; detailed contours and microrelief of the underwater canyon valleys and their fans were obtained. Two areas with mud volcanoes and gas hydrates were investigated.

For geological validation of the materials, one land route of 20 km in length was led near the Turka settlement. Along the route, two geological sections were partially uncovered, studied and documented, and five samples were taken for pollen analysis. The expedition plan was completely fulfilled.