JOINTING PATTERNS AND STRESS TENSORS IN CENOZOIC SEDIMENTS OF THE BAIKAL RIFT: DEVELOPMENT OF THE STRUCTURAL-GENETIC APPROACH
K.Zh. Seminsky and A.V. Cheremnykh
Institute of the Earth's Crust, Siberian Branch of the of the Russian Academy of Sciences, ul. Lermontova 128, Irkutsk, 664033, Russia
Keywords: Tectonic joints, Cenozoic sediments, structural-genetic analysis, stress tensor, Baikal rift
Pages: 353-367
Abstract
Mass measurements of joints in Cenozoic sediments from the Baikal rift have yielded statistical data suitable for processing with a new structural-genetic approach. In the course of processing, the new approach has been methodologically completed with formalized techniques for proceeding from local stress tensor reconstructions to regional-scale stress patterns. The jointing patterns in soft sediments of the area have been recognized to be basically of tectonic origin, and their seeming fuzziness to result from spatial and hierarchic variations during rifting-related stress and strain changes. The patterns vary in time, space, and hierarchy, the three kinds of variability being associated, respectively, with stages of rifting and failure dynamics, with control from the prerift tectonics, and with the existence of six hierarchic levels of stress tensors. For the latter, the complete hierarchy of six stress levels has been recognized for the first time in the Pribaikalian crust.
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