STRATIGRAPHICAL AND SEDIMENTOLOGICAL STUDIES ON THE MAASTRICHTIAN- PALEOCENE SEQUENCE OF THE AREA BETWEEN GEBEL EL-BARQA AND DUNGUL, SOUTH WESTERN DESERT, EGYPT.

Abstract

The present thesis is dealing with stratigraphical and sedimentalogical studies on the Maastrichtian- Paleocene succession exposed in the area southwest of Aswan, along the Sinn El Kaddab Scarp, between Gebel El Barga to the North and Bir Dungul to the South. It is based on six columnar sections, measured at Gebel El Barga, Gebel Abu Domi, Kurkur Oasis, Wadi El Sana, North ofBarq El Sahab, and Dungul Oasis localities. Lithostratigraphically, the Maastrichtian - Paleocene sequence of the study area, has been subdivided into the Dakhla Formation unconformably overlain by the Kurkur Formation. The measured stratigraphic seq••ence overlies clastic sediments of the Nubian facies and underlies the carbonate beds of the Garra Formation. Palaeontological analysis of the collected macrofauna has led to the identification of 73 macrofossil species belonging to 3 phyla, 5 classes, 32 families, and 47 genera. The identified fauna consists of 35 bivalve, 27 gastropod, 3 cephalopod, 6 echinoderm, and 2 vertebrate species. They have been photographed and systematically described. The bivalves Venericardia incurvata and Tel/ina truncala of Maastrichtian age, and the Odontogryphaea uncinata of Paleocene age have been introduced as new taxa. Trophic groups, mode of life and relation to substratum of the identified fauna have been discussed and used as a tool to deduce the palaeoecological and paleoenvironmental conditions prevailed, the study area during the Maastrichtian-Pasleocene time. In terms of paleoecological zones, the fossiliferous Maastrichtian- Paleocene sequence of the study area has been classified into eight benthic macrofauna! assemblages. Biostratigraphically, the Maastrichtian- Paleocene sequence of the study area has been subdivided into 9 molluscan biozones. They are the Maastrichtian. Venericardia vredenburgi, Exogyra overwegi, Cameleolopha pauciplicata, Venericardia garmusheenensis- Chlamys acuteplicatus, Pholadomya lucerna zones, and the Paleocene Venericardia libyca, Venericardia wegeneri, Gitolampas abundance, and He/icostrea osiris zones. The proposed biozones have been correlated with other zonal schemes. The Dakhla Formation yields the first six biozones