TOPOGRAPHY AND GENESIS OF THE MURINSKAYA BANKA UNDERWATER UPLAND (SOUTHERN BAIKAL)
O. M. KHLYSTOV1, E. E. KONONOV1,2, H. MINAMI3, A. V. KAZAKOV1,2, A. V. KHABUEV1, N. A. GUBIN4, D. A. CHENSKII4, A. G. CHENSKII4, A. N. SUTURIN1
1Limnological Institute SB RAS, 664033, Irkutsk, Ulan-Batorskaya str., 3, Russia
oleg@lin.irk.ru
2V. B. Sochava Institute of Geography SB RAS, 664033, Irkutsk, Ulan-Batorskaya str., 1, Russia
ekon@7395.ru
3Kitami Institute of Technology, 165 Koen-cho Kitami, Hokkaido 090-8507, Japan
minamihr@mail.kitami-it.ac.jp
4National Research Irkutsk State Technical University, 664074, Irkutsk, Lermontova str., 83, Russia
gubin.1@yandex.ru
Keywords: тектоника, осадконакопление, стратиграфия, геоморфология, картирование, палеореконструкции, tectonics, sedimentation, stratigraphy, geomorphology, mapping, paleoreconstructions
Abstract
We present new data on the morphology of Murinskaya Banka (Southern Baikal) obtained during specialized expedition investigations by using the high-resolution multibeam echosounder, and the acoustic profile recorder system. The set of bathy metric data was subjected to a pre-assessment in the ArcGISforDesktop software package to construct the terrain model using the 3D-Analyst Module by the method of TIN interpolation based on a Delaunay triangulation. The MeshDenoise smoothing method, developed specifically for processing volumetric data, was used to eliminate all errors as revealed in the model after its analysis. For the first time for this upland, we obtained and analyzed, along with data from the multibeam echosounder, seis moacoustic data. We assessed the age boundaries of the epochs in the history of formation of Murinskaya Banka, including on the basis of palynological data on samples obtained by means of Deep Submergence Vehicle Mir. As a result, a detailed bathy metric map was constructed for the first time for the underwater upland, unconformities and faults in its internal structure were revealed, and the sedimentary genesis of its body was determined. By studying the morphological characteristics of the shoalbank and the adjacent territory of the coastland, it was found that the formation of the underwater upland was associated with the submergence of the coastal plain and the ancient delta of the Khara-Murin and Langatui rivers beneath the lake water line. This event could occur during the lake substage of the Neobaikalian stage that started about 0.15 million years ago. Nowadays there is taking place a rise of the shoalbank itself and of the coast, which is evidenced by intense incisions of the rivers flowing into the lake, and of the canyons.
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