PALEOBIOGEOGRAPHY AND PALEOECOLOGY OF LATE BATHONIAN BRACHIOPODS FROM GEBEL ENGABASHI, NORTHERN SINAI

A brachiopod fauna of Late Bathonian age recovered from strata in a thick Pliensbachian-Oxfordian sedimentary sequence at Gebel Engabashi in northern Sinai consists of six species (two rhynchonellids and four terebratulids) referred to six genera. The brachiopods comprise a fauna located at the northern part of the Indo–African Realm within the Jurassic Ethiopian Province. The present records extend the geographic distribution of those taxa that show great affinity with the Jurassic brachiopod fauna from Saudi Arabia described by Cooper in his 1989 monograph. During the Early Bathonian there was a substantial regression in the area, as evidenced by paralic coals in the Safa Formation. Paleoenvironmental conditions prevailing during the deposition of the Safa Formation can be subdivided into two phases. The lower two-thirds of a thick alternating shale and sandstone sequence are unfossiliferous and are characterized by primary sedimentary structures such as cross-stratification and plant remains of continental, probably fluviatile origin. These sediments, usually ferruginous, are characteristically brown or red due to a regressive phase resulting in rivers and streams depositing terrigenous, iron oxide-rich sediments. The upper third of the Safa Formation is characterized by shallow marine facies, consisting of marly and oolitic limestones and marly shales that signify the beginning of a transgressive phase. The shoreline of this transgression is marked by coralline limestone with coral heads. The faunal assemblage typical of these sediments (brachiopods, molluscs, corals, and rare echinoderms) supports a shallow marine depositional environment.