Late Cretaceous-Early Tertiary Dextral Transpression in North Sinai: Reactivation of the Tethyan Continental Margin

Adel R. Moustafa, Mosbah H. Khalil

Detailed photogeologic study and field checks indicate the North Sinai folds are associated with northwest-dipping upthrusts, especially on their southeastern steeply dipping flanks. These northeast-southwest-plunging folds include both large folded ranges (tens of kilometers long, e.g., Gebels Yelleq, El Maghara, and El Halal) and smaller folds (2-10 km long). The smaller folds have right-stepping en echelon arrangement and define six east-northeast elongated belts which were probably formed by right-lateral wrenching in Late Cretaceous-early Tertiary time. These belts are called the G. El Amrar belt, the G. El Mistan belt, the G. Um Latiya belt, the G. Falig belt, the El Giddi Pass-G. El Minsherah-G. El Burqa belt, and the Mitla Pass-G. Kherim-G. Araif El Naqa belt. The existence of northwest-dipping upthrusts within and between these en echelon fold belts probably indicates the wrenching was convergent.

The en echelon fold belts are proposed to overlie pre-existing deep-seated faults which could have been formed by the Late Triassic-Liassic rifting of north Africa-Arabia to form the southern passive continental margin of the Tethys sea. Mesozoic rocks thicken across these faults. Late Cretaceous-early Tertiary reactivation of these faults by dextral transpression probably resulted from the oblique movement between Africa and Eurasia to close the Tethys sea.

AAPG Search and Discovery Article #91032©1988 Mediterranean Basins Conference and Exhibition, Nice, France, 25-28 September 1988.