The Initiation of the Dead Sea Rift

An earlier theory proposed that the Dead Sea Rift started as a shear transform between the Arabian and African plates as a result of continental collision. Newer geological evidence implies a different mechanism for rift initiation. Mechanical theories and experimental results suggest that fracture initiation, propagation, and bifurcation along the Rift cannot be explained by shear. These features can best be explained and simulated by extensile processes. Recent discoveries of transitional properties of the crust/mantle boundary along the Rift, and considerable thinning of the crust between the Dead Sea and the Sea of Galilee on the west side of the Rift, are interpreted as indications of an active mantle diapir that initiated fracture in this area. By propagating (horizontally) bilaterally towards north and south this fracture reached conditions of bifurcation in several locations along the Rift. Areas of major bifurcation also show characteristic local uplifts and local small grabens oblique to the Rift axis. Thus, the evolution of the Dead Sea Rift is comprised of an early stage of fracture initiation by extension, with a later development into a major left-lateral strike-slip fault.