SEDIMENTARY FACIES CHARACTERIZATION OF OMDURMAN (UPPER CRETACEOUS) FORMATION, KHARTOUM SEDIMENTARY BASIN, KHARTOUM, SUDAN

Abstract

The study area is located in Khartoum, Khartoum State, central Sudan. The research dealt with studying the ancient depositional environments, architecture, facies types, and sedimentary paleogeography of the Omdurman Formation (Upper-Cretaceous), northern part of the Khartoum Basin. Few studies were conducted in the study area, so this study will add more clarity to the Basin, fieldwork was conducted, geological observations were recorded, in addition to grain size analysis was done by using the sieve analysis technique. Lithofacies analysis indicates that the Omdurman Formation contains matrix-supported conglomerate (Gm), trough cross-bedded sandstone facies (St), plane cross-bedded sandstone facies (Sp), laminated silt facies (Fl), and massive mudstone facies. (Fm). In this member (Al-Markhiyat) coarse facies are common and some fine facies appear such as the alluvial facies (Fl) and the massive mudstone facies (Fm). This facies was deposited by braided, slightly meandering rivers characterized by shallow channels. The second, which is the bottom, is called the Umbada Member, as this member shows fining upward facies sequences of vertically accumulated sediments of channels and islands. The depositional model of the Omdurman Formation can be represented by a coarse-upward depositional cycle that appears to be controlled by internal and external factors.