Lateral motion and deformation along the Dead Sea transform

Abstract

This paper presents an updated summary of the history and shallow structure of the Dead Sea transform (DST) and its plate tectonic context. The DST formed in the Early Miocene as a transform boundary between the Sinai and Arabian plates. The lateral offset was ca. 105 km near the Dead Sea. Since the DST trace is irregular in map view, the lateral motion led to formation of a 10-80 km wide deformation zone along the plate junction. Thus, the structures along the DST can be interpreted within the framework of the Sinai-Arabia plate kinematics. South of ca. lat. 33° transtension, which increased with time, led to variable oblique separation of the plate edges. This produced an almost continuous ca. 5-25 km wide depression whose structure is dominated by a string of pull-apart basins up to 15-20 km wide and up to ca. 12 km deep. The crystalline crust under the largest basins was appreciably thinned and may have been intruded by basalts. The structural pattern changed over time, the present pattern having been mostly established in the second half of the DST history. North of lat. ca. 33°N transpression dominates and the DST flanks are strongly deformed by folding, faulting, and rotation of fault blocks on vertical axes, which together produce shortening perpendicular to the DST and also left lateral shearing of its flanks, qualitatively compatible with the plate kinematic. The deformation can also account for the observed decrease of the lateral offset along the main fault line from ca. 100 km at ca. lat 33°N to 65-70 km at lat. 36°-36.5°N, and also leads to left lateral shearing along the continental margin near the Galilee and farther north. North of lat. 36.5°N the DST now interacts with the Anatolian plate and the Cyprus arc. This resulted from a rearrangement of the plate configuration in that region when westward extrusion of Anatolia began and the East Anatolian Fault formed, but the details of the kinematic changes are incompletely known. This change obscured the structural relations in this region during the early stages of the DST history.