Almost a sharp cut – A case study of the cross point between a continental transform and a rift, based on 3D gravity modeling

Abstract

Transform faults displace older structures crossing their paths, marking a visible shift between the two sliding plates. The fate of these pre-transform structures within the damage zone is less understood, and so is the dynamics of plate boundaries and their changes through time – To what extent are they preserved and what structural heritage do they dictate? The current study focuses on a crossing region between the Oligo-Miocene NW-trending Irbid rift and the N-trending Miocene to recent Dead Sea Transform (DST). The structural heritage aspect is examined through 3D forward modeling of gravity data across the Kinneret-Kinarot-Beit-She'an (KKB) basin complex of the DST. The model includes pre-Senonian to recent formations, highlighting key volcanic and evaporitic units. By modeling the depth, thickness, and 3D density distribution of each lithological unit the study constructs the volumetric geometry of the sub-basins and suggests central stages in its geological development: the southern, Beit-She'an, basin began as part of the Irbid rift and was later hijacked by the younger DST at the transform-rift cross region. The transform displacement initiated en-echelon mini-basins from the Beit-She'an basin northwards to form the proto Kinarot and Kinneret (Sea of Galilee) basins. Volcanic phases record the deformation, leaving a reliable time frame for the subsidence mode, faulting and the role of salt tectonics. During the late Miocene the lateral displacement formed a trishear structure that evolved by the Plio-Pleistocene into the Kinneret-Kinarot-Beit-She'an complex, bounded by longitudinal faults stemming from a single deep-rooted fault.