CRUSTAL STRUCTURE OF THE NORTHERN LEVANT REGION - MULTIPLE SOURCE WERNER DECONVOLUTION ESTIMATES FOR BOUGUER GRAVITY-ANOMALIES

The opening of the Gulf of Aden and the Red Sea, and the collision of the Arabian plate with the jigsaw southern margin of the Anatolian pla te have sheared the Sinai Levant microplate off the NW part of the Ara bian plate, and created the left-lateral Dead Sea (Levant) transform f ault. The structural setting of the northern Levant region, particular ly Lebanon and the Palmyrides, has been complicated by detachments alo ng incompetent evaporitic horizons, roughly separating the post-Triass ic succession from the underlying crustal material. The interpretation of the multiple source Werner deconvolution (MSWD) estimates of Bougu er gravity profiles, which were separately calculated for Syria and Le banon, integrated with the available geological and geophysical result s leads to the following interpretations: (1) the crust of Syria thick ens southeastwards from approximately 32 km under the Al-Ghab Graben t o >36 km under the Aleppo high, the Palmyride fold belt and the Rutbah high; (2) the lower-crustal (basaltic) layer thickens northwestwards from the hinterland to the Al-Ghab graben at the expense of the overly ing andesitic layer; (3) the Mid-Beqa'a fault is delineated by the MSW D estimates in Lebanon and its NE extension in Syria; (4) the Phaneroz oic section in the southwesternmost parts of the Palmyrides is similar to 13 km thick, and the shortening there could exceed 30 km; (5) the Palmyride fold belt, and the Serghaya and Mid-Beqa'a faults could have accounted for about 70 km of the 105 km left-lateral displacement alo ng the southern segment of the Dead Sea transform fault system, withou t transmission to the Syrian (northern) segment of the fault system; ( 6) the splitting of the Dead Sea transform fault in the Huleh Depressi on into the Serghaya, Mid-Beqa'a, Yammouneh and Roum faults could be e xplained by the rotation of the detached post-Triassic succession over a stable deep left-lateral fracture of the Dead Sea fault in the unde rlying crustal material.