Abstract

VIZAN, Haroldo et al. Tracción de losa en el margen boreal del océano paleotetis y deformación en el interior de Gondwana (incluyendo el cordón plegado de Ventana). Rev. Asoc. Geol. Argent. [online]. 2015, vol.72, n.3, pp.355-377. ISSN 0004-4822.

During the late Paleozoic several tectonic processes took place within Pangea generating structures known in different parts of our planet. In order to relate these processes to geodynamic causes, absolute paleoreconstructions of Gondwana were performed, using paleomagnetic data, for two time spans: 1) Pennsylvanian (Late Carboniferous)-Guadalupian (Middle Permian) and 2) Lopingian (Late Permian)-Middle Triassic. To achieve a better fit of Gondwana paleopoles different lithospheric domains separated by deformed belts located along circumference arcs were considered. Through the reconstructions, displacement vectors that indicate a SW-NE movement of different Gondwana domains were determined. During the Late Paleozoic, the mantle would have presented a large downwelling area in the hemisphere where Pangea was assembled through the union of Gondwana with Laurasia. Thus, the Rheic ocean would have closed and an active subduction zone would have remained active in the northern margin of the Paleothetys ocean. The slab pull in this margin would have generated different tectonic processes. In Western Gondwana, the mentioned slab pull would have caused counterclockwise rotations of different lithospheric domains through strike-slip mega-fault zones. This process would have induced toroidal flows in the mantle, whose vortices would have been located at the centers of the arcs along which the lateral displacements between the domains would have been channelized. These movements, coupled with a fast south-north displacement of Pangea, would have had vital importance in the deformation of different localities for which SW-NE directions of stress coherent with the orientation of the calculated displacement vectors have been suggested. The Ventana fold belt would be one of these localities.

Keywords : Gondwana; Geodynamics; Intraplate deformation; Toroidal flux.