Palaeontological and biometrical studies oil some Late Cretaceous macroinvertebrate fossils of the Galala area, north Eastern Desert, Egypt

Abstract

The present Thesis deals with palaeontological and biometrical studies on some macroinvertebrate fossils collected from six Upper Cretaceous outcrops, the Galala area, north Eastern Desert of Egypt. It is confined mainly to the bivalves, presenting a detailed systematic work as well as biometrical, microstructural and functional analyses of certain oysters. The study presents also a detailed litho-and bio-stratigraphical classification for the Upper Cretaceous sequence of the measured sections. Lithostratigraphically, the compiled fossiliferous Upper Cretaceous sequence exposed in the study area is subdivided, from top to base, into: Gebel Thilmet Formation, Sudr Formation, Duwi Formation, Hawashiya Formation, Umm Omeiyid Formation, and Galala Formation. The study sequence is unconformably overlying the Pre-Cenomanian continental sandstone succession of the Malha Formation and underlying a carbonate succession of the Tarawan Formation. Correlation charts for the recognized rock units are constructed. In The present study, 127 bivalvian species belonging to 42 subgenera, 65 genera, 24 subfamilies and 28 families have been identified and systematically described. They include one new subgenus, and 10 new species. 46 taxa are recorded for the first time from Egypt. 34 species, of the previously known bivalves are endemic to Egypt, suggesting that Egypt was an endemic center during certain times. Biostratigraphically, the study sequence has been subdivided into 13 bivalvian zones of Late Cenomanian -Maastrichtian age.