The Arabian Infracambrian extensional system

Abstract

During the Late Precambrian and Early Cambrian (about 600-540 Ma) extensive left-lateral faulting along the complex NW-SE-trending Najd fault system cut across the Arabian shield. This tectonic episode was accompanied by NW-SE-directed extension in northern Egypt and the Sinai peninsula. Based on these relationships, Stern (1985) interpreted the Najd fault system as a set of transform faults emanating from a rift basin in NE Egypt. Contemporaneous to this system in the western part of the Arabian plate and northern Egypt, extensive evaporitic basins developed in northern Pakistan, southern Oman and the Arabian Gulf and Zagros Mountains. These basins are generally bounded by NW-trending faults, such as the Najd, Hawasina and Zagros faults, and NE-trending faults, such as the Ghudun-Khasfah and Dibba faults. These evaporitic basins are interpreted as rift basins, such that Stern's (1985) extensional model, in northern Egypt, may be expanded regionally to include the eastern part of the Arabian plate and the Indian subcontinent. This broader interpretation implies that after the E-W-directed collisional tectonics of the Late Precambrian in western Arabia and Africa, which terminated around 640-600 Ma, the Arabian plate experienced NW-SE-directed crustal extension and continental break-up.