Anatomy of an Intracratonic Fold Belt: Examples from the Southwestern Palmyride Fold Belt in Central Syria
CHAIMOV, THOMAS A., MUAWIA BARAZANGI, and JOHN A. BEST, Cornell University, Ithaca, NY, and DAMEN AL-SAAD, TARIF SAWAF, and ALI GEBRAN, Syrian Petroleum Company, Damascus, Syria
The Palmyride fold belt, a 400 X 100 km, NE-trending, transpressive belt in central Syria, represents the late Mesozoic and Cenozoic inversion of a linear intracratonic basin. The southwestern Palmyrides are characterized by short wavelength (2-5 km) folds separated by small intermontane basins. To elucidate the subsurface structure, a three-dimensional model, based mainly on about 450 km of two-dimensional seismic reflection data, was generated using a LandMark(trademark) graphics workstation. The new model includes many features not identified in outcrop. Short, NW-trending transcurrent, or transfer, faults link the short, en echelon NE-trending thrust faults and blind thrusts of the Palmyrides. Varying structural styles are observed within the southwestern part of the belt. In one nstance the structure of Mesozoic and Cenozoic rocks mimics that in deeper Paleozoic rocks; elsewhere, a strong discordance between Paleozoic and Mesozoic rocks appears to be related to the development of a regional detachment in Triassic rocks at about 4 km depth.
Shortening in the southwestern Palmyrides totals about 20-25 km, based on palinspastic restoration of a balanced cross section across the belt. Seismic stratigraphy constrains the timing of at least three distinct episodes of Palmyride shortening: Late Cretaceous, middle Eocene, and Miocene to present. All three episodes were penecontemporaneous with specific tectonic events along the northern Arabian plate boundaries. The Late Cretaceous initiation of inversion in the Palmyrides, an integral part of the Syrian Arc, which extends from the Palmyrides southward to include the Negev fold belt of central Sinai, apparently predates development of the Red Sea/Dead Sea plate boundary. In contrast, the Neogene through Quaternary intense deformational episode is clearly related to development f the Red Sea/Dead Sea fault system and to convergence along the northern boundary of the Arabian plate in southern Turkey.
AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)