Transtension in the Levant Basin: Challenging the Syrian Arc model

Late Cretaceous intra-plate shortening, and inversion of the Permian to Jurassic rift system, resulted in the ~1000 km-long, S-shaped Syrian Arc Fold Belt which dominates the Levant regional topography through Egypt, Israel, Lebanon, and Syria. Subsequent Miocene folding along the same trends of the Late Cretaceous fold belt, was likely associated with the collision of Arabia and Eurasia. The kinematic model detailing how the Miocene collision initiated the observed inversion is currently unclear yet is essential to our understanding of the geological development of this tectonically complex region. We here present a borehole-constrained seismic-stratigraphic interpretation of 3D seismic reflection data from the Levant Basin that provides unparalleled imaging of these Oligocene-Miocene folds. We show that one of the structures, the NE-SW trending Tamar Anticline, formed during the Burdigalian (lower-Miocene) with no indication of a precursor phase of Late Cretaceous inversion, as previously suggested. We show how the Tamar Anticline was formed concurrent to movement on adjacent strike-slip faults and to the dissection of the anticline by NW-SE-striking normal faults. Simultaneous NW-SE-directed shortening and NE-SW-extension, related to motion along ~E-W strike-slip faults suggests the Tamar Anticline and similar structures developed during the Miocene folding phase formed due to transtension, driven by the opening of the Red-Sea. This new geodynamic model highlights that Late Cretaceous and Miocene folding associated with the Syrian Arc Fold Belt may be geometrically comparable, but stem from different geodynamic regimes.