The tectonic style of the southern Arava Rift margins, Israel: alternating stress fields in wrench-rifting processes

The Arava Rift segment of the Dead Sea Transform contains juxtaposed transtensional and transpressional tectonic elements. This structural pattern is related to the disposition of individual, en-echelon faults which accommodate the horizontal slip with respect to the regional stress field. A detailed study of mesostructural elements across two transpressional structures at the western margins of the Arava Rift has established a tectonic sequence and subsequent adjustment of the concurrent drainage systems. The studied structures are the Shizafon Disturbance, an array of narrow asymmetric monoclinal and anticlinal folds and the Ya'alon Graben, a left-lateral, branching wrench fault, with some downfaulted internal blocks. Slickensides on small faults, small-scale rhomb-grabens, veins with secondary mineralization and tectonic stylolites indicate that during an early compressional phase (Miocene-Lower Pliocene) the main horizontal compressional component (σ₁) trended NW at the Shizafon Disturbance and NW to NNW at the Ya'alon Graben. Normal faulting commenced during the Middle Pliocene and formed antithetic blocks along the rift margins. Similarly alternating stress fields, whereby compression was succeeded by extension are recorded also several hundred kilometres further north along the transform margins. The extensive distribution of coeval events along the eastern Sinai plate margin calls for a regional stress field, most probably a change in the rotation pole of the plates bordering upon the Dead Sea Transform, of the sort implied by Garfunkel (1981). Due to the thin sedimentary cover (<1.3 km), deformation of the basement must have played an important role in the localization of structures in the sedimentary succession.