LITAK, ROBERT K., MUAWIA BARAZANGI, DOGAN SEBER, and DOUGLAS ALSDORF, Institute for the Study of the Continents, Cornell University, Ithaca, NY; and DAMEN AL-SAAD, TARIF SAWAF, WASSIF AL-YOUSSEF, and MOHAMMED KHADDOUR, Syrian Petroleum Company, Damascus, Syrian Arab Republic

ABSTRACT: Tectonic History of the Intraplate Palmyride Mountain Belt and Surrounding Regions, Syria

Abundant seismic reflection and refraction profiles, supplemented by well, potential fields, and geologic data, are used to infer the structure and evolution of the intraplate Palmyride mountain belt and surrounding regions in Syria, where exploration activity has recently intensified. The NE-striking Palmyrides may have been the site of a Proterozoic suture that has been reactivated in Mesozoic and Cenozoic times by extension, compression and strike-slip motion.

Bouguer gravity modeling requires differences in crustal structure north and south of the Palmyrides, suggesting that they may occupy the location of a (Proterozoic?) suture between two blocks that now constitute the northern Arabian plate. The Palmyrides were subsequently the locus of early Mesozoic aulacogen-type extension related to the Levantine rifted margin in the eastern Mediterranean. Seismic stratigraphic analysis indicates that uplift of the Palmyride depression initiated in the Late Cretaceous, penecontemporaneous with emplacement of ophiolites in southern Turkey. More intense shortening during the Cenozoic also appears to be temporally related to collision along nearby plate boundaries, implying that stresses have been transmitted hundreds of kilometers across the northern Arabian platform.

Style and intensity of Palmyride deformation varies considerably along strike. Shortening of 20-25% in the southwest gradually dies out to the NE near the intersection of the Palmyrides with the NW-trending Euphrates Depression. The latter is the site of Mesozoic graben overlain by a Tertiary basin. Refraction data indicate that depth to metamorphic basement beneath the Palmyrides increases from 9 km in the northeast to 11 km in thesouthwest, compared with a basement depth of about 6-8 km in the adjacent Arabian platform, indicating that shortening across the Palmyrides has been insufficient to invert the previously extended basement morphology.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.