Publications

The Dead Sea transform system (DST) is the boundary between the Arabian and African plates, where left-lateral transform motion has largely accommodated the opening of the Red Sea basin during the last 15-20 My. One of the key questions related to this plate boundary is whether the DST crosses the crust and mantle lithosphere, and how the rheologically different units composing the lithosphere interact during strong deformation? Another major question is how important is the rifting (transform-perpendicular extension) deformation component at the DST? We address these questions using the internally consistent finite element thermo-mechanical modelling of the lithospheric deformation constrained by high-resolution geophysical observations and especially by the recent geophysical data of the DESERT Project. From our modelling, we conclude that the DST lithospheric structure is controlled by the plate-scale transform displacement within a relatively cold and strong lithosphere. In such a lithosphere, shear strain is localized in a narrow (20-40 km wide) vertical decoupling zone (VDZ), which crosses the entire lithosphere and even continues into the asthenosphere. In the upper crust the deformation localizes at one or two major faults located at the top of this zone. The location of the VDZ is controlled by the temperature of the uppermost mantle prior to the transform motion. Most of the lithospheric structures imaged along the DESERT seismic line is explained by the 105 km transform motion combined with less than 4 km transform-perpendicular extension. Uplift of the Arabian Shield adjacent to the DST can be explained by young ($<$20 Ma) thinning of the lithosphere at and east of the plate boundary. Such lithospheric thinning is consistent with seismological observations, with the low present-day surface heat flow and with the high temperatures derived from mantle xenoliths brought up by Neogene-Quaternary basalts. Taking into account the timing of the onset of the volcanism, we suggest that the lithospheric thinning in the southern part of the DST, likely related to the opening of the Red Sea, may have enabled transform motion at the DST by lowering the strength of the Arabian Shield lithosphere.

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Sobolev, S. V.; Babeyko, A. Y.; Garfunkel, Z. (2002): Thermo-mechanical model of the Dead Sea Transform. AGU 2002 Fall Meeting (San Francisco 2002).