HR: 1340h
AN: T43A-1088    [Abstracts]
TI: Formation of deep basins along strike-slip fault systems: The Dead Sea fault
AU: * Ben-Avraham, Z
EM: zviba@post.tau.ac.il
AF: Department of Geophysics and Planetary Sciences, Tel-Aviv University, Tel-Aviv, 69978, Israel
AU: Lyakhovsky, V
EM: vladi@geos.gsi.gov.il
AF: Geological Survey of Israel, 30 Malkhei Israel, Jerusalem, 95501, Israel
AU: Schubert, G
EM: schubert@ucla.edu
AF: Department of Earth and Space Sciences, University of California, Los Angeles, CA 90095- 1567, United States
AB: Sedimentary basins are often formed along strike-slip fault systems. The Dead Sea fault is associated with some large and unusually deep basins. The width/depth ratio of these basins is often less than 1. In areas where the deep basins occur, two strands of the Dead Sea fault overlap in an en echelon pattern. This situation is quite rare along the Dead Sea fault; normally most basins are bordered only on one side by a strand of the Dead Sea fault, leading to their asymmetry. Geophysical data suggest that the deep basins are probably bordered on all sides by vertical faults that cut deep into basement. It has been previously proposed that in the deepest basin, at the southern Dead Sea, an isolated block of crust and lithosphere has dropped into the mantle. In this presentation we investigate the mechanism of formation of this and other deep basins along the Dead Sea fault and propose that dropping down of pre-existing heavy magmatic bodies into the mantle took place in these regions. Density heterogeneities formed in the crust or upper mantle during a previous stage of regional magmatism, drop into the upper mantle when strike-slip faults are created that detach them from the surrounding lithosphere. The suggested mechanism of deep basin formation is supported by the results of three- dimensional numerical simulations of spatial-temporal evolution of seismicity patterns and faults in a regional lithospheric model of crustal deformation and self-organization of regional earthquakes and faults. The simulations indicate that the resulting basin is rhomb-shaped and that with time it grows by the addition of distinct segments to its edges. The proposed mechanism could account for the formation and evolution of large sedimentary basins along other strike-slip fault systems, such as the San Andreas fault and other continental transform faults.
DE: 8109 Continental tectonics: extensional (0905)
DE: 8111 Continental tectonics: strike-slip and transform
SC: Tectonophysics [T]
MN: 2007 Fall Meeting