Integrated 3D density modelling and segmentation o

Authors: HJ Götze R ElKelani S Schmidt M Rybakov M Hassouneh HJ Förster J Ebbing

Publish Date: 2006/05/31

Volume: 96, Issue: 2, Pages: 289-302

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Abstract

A 3D interpretation of the newly compiled Bouguer anomaly in the area of the “Dead Sea Rift” is presented A highresolution 3D model constrained with the seismic results reveals the crustal thickness and density distribution beneath the Arava/Araba Valley AV the region between the Dead Sea and the Gulf of Aqaba/Elat The Bouguer anomalies along the axial portion of the AV as deduced from the modelling results are mainly caused by deepseated sedimentary basins D  10 km An inferred zone of intrusion coincides with the maximum gravity anomaly on the eastern flank of the AV The intrusion is displaced at different sectors along the NNW–SSE direction The zone of maximum crustal thinning depth 30 km is attained in the western sector at the Mediterranean The southeastern plateau on the other hand shows by far the largest crustal thickness of the region 38–42 km Linked to the left lateral movement of approx 105 km at the boundary between the African and Arabian plate and constrained with recent seismic data a small asymmetric topography of the Moho beneath the Dead Sea Transform DST was modelled The thickness and density of the crust suggest that the AV is underlain by continental crust The deep basins the relatively large intrusion and the asymmetric topography of the Moho lead to the conclusion that a smallscale asthenospheric upwelling could be responsible for the thinning of the crust and subsequent creation of the Dead Sea basin during the left lateral movement A clear segmentation along the strike of the DST was obtained by curvature analysis the northern part in the neighbourhood of the Dead Sea is characterised by high curvature of the residual gravity field Flexural rigidity calculations result in very low values of effective elastic lithospheric thickness t e  5 km This points to decoupling of crust in the Dead Sea area In the central AV the curvature is less pronounced and t e increases to approximately 10 km Curvature is high again in the southernmost part near the Aqaba region Solutions of Euler deconvolution were visualised together with modelled density bodies and fit very well into the density model structuresWe wish to thank the DESERT Working Group at the GeoForschungsZentrum GFZ Potsdam for providing “constraining data” and their ongoing interest In particular we are thankful to D Kesten N Maercklin J Mechie C Haberland A Förster S Sobolev N Balling reviewer and an anonymous reviewer for useful discussions and suggestions and especially M Weber the leader of the DESERT project for many discussions and his valuable comments on an earlier version of this paper Many thanks to J Mechie for his careful language editing R ElKelani and M Rybakov would like to thank the Deutsche Forschungsgemeinschaft DFG and the GeoForschungsZentrum GFZ Potsdam for financing their sabbatical during this research We are thankful to the Natural Resources Authority NRA of Jordan and the Geophysical Institute of Israel GII for providing their databases The gravity research was funded by the Deutsche Forschungsgemeinschaft DFG

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