Morfoneotettonica del lago Baikal e della Tunka Valley (U.R.S.S.)

Morphoneotectonics of Lake Baikal and the Tunka Valley (U.S.S.R.)

Abstract

 Lake Baikal fills a rift basin which began its formation during the Late Cenozoic and is still expanding. In fact, the southwestern shore of the Baikal basin corresponds to a high, steep tectonic scarp created by the rejuvenation of an ancient fault zone. Uplifts of approximately 10 mm annually have been recorded recently. The part of the scarps outcropping above water is characterized by slopes carved in a system of triangular and trapezoidal facets. The Tunka Valley is an intermontane rift valley that extends in a W-E direction from the western end of Lake Baikal. From a neotectonic point of view, the lake is a succession of basins that are rather complex and separated by positive structures and tectonic steps. The northern side of the valley is lined with active faults that are characterized by numerous and distinct geomorphological signs. Manifestations of basaltic volcanism linked to the rifting activity have taken place since the Late Cenozoic. The most recent eruptions occurred approximately 10,000 years ago.