SIMULATION OF STRESSES IN THE HEATING LITHOSPHERE OF THE BAIKAL RIFT AT THE ONSET OF RIFTING
A.N. Adamovich, S.I. Sherman, and S.V. Ivanova
Institute of the Earth's Crust, Siberian Branch of the RAS, 128 ul. Lermontova, Irkutsk, 664033, Russia
Keywords: Stress field, thermal anomaly, finite element simulation, Baikal rift
Pages: 276-284
Abstract
Evolution, space and time dynamics of stresses, geometry of basins, and other particular features of the Baikal rift can be explained in the context of stress changes associated with rifting initiation. Rifting may have been triggered by local heating of the 70 km thick lithosphere from a sublithospheric mantle plume. The impact of heating necessary to initiate extension has been estimated in terms of a thermoelastic loading model for rift-orthogonal plane strain. Finite element simulation using the NASTRAN software reveals a mosaic stress field in heating lithosphere. The existence of different stress zones may account for the rift asymmetry, initiation and/or development of major faults, horizontal layering of lithosphere, attenuated crust, etc. The plane strain finite element model of lithosphere subjected to thermal loading provides a sound clue to understanding the driving mechanism for rift formation.
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