The onset of the Dead Sea transform based on calcite age-strain analyses

The onset and evolution of the Dead Sea transform are re-evaluated based on new insitu U-Pb dating and strain analyses of mechanically twinned calcites. Direct dating of 30syn-faulting calcites from 10 different inactive fault strands of the transform indicates thatthe oceanic-to-continental plate boundary initiated between 20.8 and 18.5 Ma within an∼10-km-wide distributed deformation zone in southern Israel. Ages from the northern DeadSea transform (17.1–12.7 Ma) suggest northward propagation and the establishment of a well-developed>500-km-long plate-bounding fault in 3 m.y. The dominant horizontal shorteningdirection recorded in the dated twinned calcites marks the onset of left-lateral motion alongthe evolving plate boundary. The observed changes in the strain field within individual faultstrands cannot be simply explained by local "weakening effects" along strands of the DeadSea transform or by gradual changes in the Euler pole through time.