Palaeontological and Biostratigraphical Studies on some Upper Cretaceous Successions in West Central Sinai, Egypt

Abstract

Upper Cretaceous successiOns are well exposed m the west central Sinai yielding rich macrofossils as well as microfossils. The present study is mainly confined to the palaeontology and biostratigraphy of the Turonian- Santonian succession with special emphasis on the Matulla Formation. Six columnar sections were measured in detail and samples for micro- and macro- fossil identification were collected throughout four field trips in west central Sinai. The measured sections are located at Gebel El-Raha, Bir Abu Rigim, Wadi El Saheimi, Gebel Heitan, Gebel El­ Minshara, and Wadi Matulla. Lithostratigraphically, the Turonian-Santonian sequence of the study area has been classified, from top to base. into: Sudr, Matulla and Wata formations. The measured lower part of the Sudr Formation is referred to Santonian age. The Marulla Formation is considered as Coniacian-Santonian in age. The measured upper part of the Wata Formation is assigned to Middle to early Late Turonian age. In the present work, a total of l 08 fossil species including 17 ammonite, 27 bivalves, 14 gastropods, 10 echinoid, and 40 planktic foraminifera have been identified and systematically described. The ammonite Buchiceras egyptiense sp.nov. and the oyster Nicaisolopha pseudonicaisei sp. nov. have been introduced as new taxa.

The identified fauna is ecologically diverse compnsmg epifaw1a, semi­ infauna. infauna. and nektonic fauna. Trophic groups, mode of life and relation to substratum of the identified fauna have been discussed and used to deduce the palaeoecological conditions and paleoenvironments prevailed the study area during the Turonian-Santonian time. The sequence studied reflects deposition in shallow manne neritic environment ranging between littoral to shallow sublittoral situation. The Wata Fom1ation was accumulated in littoral to circa-sublittoral environment.