Sankov, V.A.,  Mirosnichenko, A.I.,  Levi, K.G.,  Lukhnev, A.,  Melnikov, A.I. & Delvaux, D. 1997. ‘Cenozoic tectonic stress field evolution in the Baikal Rift Zone’. Logatchev, N.A., Curnelle, R. and Delvaux, D. (eds), Bulletin des Centres de Recherche Elf Exploration-Production 21(2), special issue : Special series of 11 articles on Recent Developments in the Geological Knowledge of the Baikal Rift System : 435-155. Pau : Elf exploration production. ISSN: 1279-8215/97/0021-0435.  (PR).

Article in a scientific Journal / Article in a Journal

Detailed investigation of Cenozoic structures in the Baikal rift zone (BRZ) revealed the existence of both extensional structures (normal faults) and compressional structures (strike-slip faults, thrusts and folding). Microstructural analysis of brittle structures and stress inversion of fault-slip data permitted the reconstruction of the Cenozoic paleostress field for the central and southwest parts of the BRZ. The presence of two different types of stress field in the spatio-temporal evolution of the BRZ is established: stress tensors of extensional "rift-type" regime and stress tensors of strike-slip to compressional "Central Asian-type" regime. The present-day stress field is reconstructed by stress inversion of earthquake focal mechanism data. Most part of the BRZ is presently in an extensional setting, with NW-trending Shmin while the southwestern part of the rift zone (Tunka basin) is in a transpressional setting. The classical two-stage evolution model of the BRZ is interpreted in function of stress field fluctuation in time and space, regular evolution of the stress field from a strike-slip or transpressional regime in the initial stage of rifting to pure extensional regime in the Quaternary is revealed. The Shmin direction remained stable in a NW-SE orientation during all this evolution. The southwestern segment of the BRZ marks the transition from the "rift-type" extensional stress field, to the compressional stress field of Mongolia and of Altai. Our results rather suggest a mechanism of Baikal rift formation involving the superposition of continental-scale tectonic forces with NE trending SHmax and extensional forces generated by a mantle diaper rising beneath the southeastern boundary of the Siberian Craton.

• Inheritance of Geological Structures (IGS)
• IGCP400 - Geodynamics of Continental Rifting
• Tectonique active et risques naturels des rifts continentaux
• Continental Rift Tectonics and Evolution of Sedimentary Basins