Most of the methodologies used to validate complex strike-slip structures mainly rely on comparison with other well-known geological features or analogue laboratory models. This study adopts an approach based on the boundary element method at the regional scale to test the structural interpretation of a complex transpressional mountain range. Lebanon restraining bend represents the most prominent topographic transpressional feature along the Dead Sea Transform (DST). It consists of two mountain ranges: the Mount Lebanon and the Anti-Lebanon ranges. We built a 3D geometrical model of the fault surfaces based on previously studied natural examples, structural maps, satellite images, DEM interpretation and experimental analogue models of restraining bend or transpressional structures. Using a boundary element method, we modelled fault deformation response to the regional stress field. The simulation accurately predicts the shape and magnitude of positive and negative topographic changes and fault slip directions throughout the study area. We propose an original approach, which uses implementation of well-known fault geometries, surface and subsurface data, for structural validation in the complex strike-slip domain. Our results, validated by structural evidences, highlight that various structural styles lead to formation of Mt. Lebanon, Anti-Lebanon and Palmyrides structures. Furthermore, this simulation supports the hypothesis that the restraining bend of the DST formed in the widespread crustal weakness zone developed in the Late Jurassic to Early Createceous. We also propose recent Neogene tectonic evolution of the region based on our modelling and integrated with published U/Pb dating of fault zones and tectonostratigraphic evidence.
Bibliographical noteKAUST Repository Item: Exported on 2022-11-28
Acknowledged KAUST grant number(s): 4082
Acknowledgements: This study was completed under KAUST’s Competitive Research Grant 4082 on “Geologic Evolution of the Red Sea and Gulf of Aqaba”. We thank colleagues Dr. Antoine Delaunay (KAUST) and Dr. Roberto Basili (INGV) for stimulating discussions. We also thank Petroleum Experts (Petex) for providing an academic licence of the Move software for numerical modelling. We acknowledges the resources made available by the SISMOLAB-3D at INGV. Seismicity catalogue was provided from CNRS Lebanon—National Center for Geophysical Research.
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