Mesorelief of the Submarine Academician Ridge in Lake Baikal (Based on Newly Gathered Instrument Readings)

This article presents the results of analyzing the topography of the Academician Ridge based on an array of detailed bathymetric data from a multibeam echosounder. It is established that the surface of the ridge and its sides are dominated by fault ledges linearly elongated to the northeast. The ledges form slope surfaces and create the asymmetrical shape of the cross profile of the ridge. The summit surface of the ridge in its southwestern and central sections is complicated by ridge-and-ravine and hummock-and-hollow topography, the formation of which may presumably be associated with landslide processes, fault tectonics, and seismic activity of the territory. The rectilinear or slightly curved shapes in the central part of the ridge might have been created as a result of the dissection of the ledge of the Academician fault by transverse oblique faults. Some of these faults might have inherited the tectonic pattern of longitudinal and transverse fractures in the basement and sedimentary strata. The assumption about the formation of hummock-and-hollow topography and some linearly elongated relief forms as a result of bottom-current activity is not confirmed by the conducted studies. The southeastern slope of the ridge is complicated in the southwestern part by ridge-and-ravine topography and in the central part by steplike terraces of tectonic origin, as well as ridges of mud volcano complexes. The formation of landslides near the Big Ushkan Island in the second half of the Holocene is associated with seismotectonic activity of the territory. The established features of the relief of the ridge indicate that its creation and further development were shaped primarily by tectonic movements of different ages and by modern seismotectonic processes.