Abstract: Structure and Tectonic History of the Northern Arabian Platform Along the Euphrates Trend, Syria

Robert Litak, Muawia Barazangi, Dogan Seber, Douglas Alsdorf, Tarif Sawaf, Wasif Al-Youssef

A lack of dramatic surface structures along the Euphrates River in Syria belie a complex tectonic history revealed by seismic and well data. Mesozoic and Cenozoic structural development and sedimentation patterns reflect the tectonic evolution of the northern Arabian platform and surrounding plate boundaries. Development of the northwest-southeast Euphrates trend as a distinct structural feature probably began in the Permian or Triassic, when it formed a ridge separating the nascent Palmyride and Sinjar troughs. The Cretaceous marked a divergence of geologic histories along the Euphrates between the areas northwest and southeast of the Palmyrides, with development of a deep Late Cretaceous graben in the southeast contemporaneous with initial uplift of the Palmyrides. Subsequent Cenozo c subsidence in eastern Syria, characterized by flat-lying seismic reflections, was probably related to the development of the Mesopotamian foredeep associated with the Zagros continental collision zone. Several major oil discoveries made in the 1980s are now producing from structures associated with the Cretaceous graben formation.

Northwest of the Palmyride intersection, several episodes of deformation are recognized. Widespread Late Cretaceous faulting produced numerous shallow half grabens in north-central Syria, whose location may be influenced by earlier structural trends. Cenozoic reverse and strike-slip deformation is likely related to continued convergence between the Arabian and Eurasian plates. The Palmyride/Euphrates intersection is marked abruptly by a right-lateral strike-slip fault system on the south and, on the north, by Cenozoic uplift of the Palmyrides (Bishri block) along a bounding fault of the Mesozoic Palmyride trough. The Palmyride Bishri block appears to be undergoing counter-clockwise rotation as it impinges on the Euphrates trend in a form of tectonic escape. The orientation of older cr stal weak zones in the Euphrates and Palmyrides may have controlled their differing responses to north-northwest-directed compressional stress.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994