ABSTRACT

During Albian-Cenomanian time, continental sediments were deposited in extensive areas of northern Sudan. In outcrops, these sediments attain a maximum thickness of about 300 m. Clastic sediments, predominantly sandstones, form the bulk of the deposits. The main depositional environments were large braidplains and coastal plains. Individual depositional histories related to different structural positions, source area distances and regional palaeoclimates caused the deposition of distinct regional lithofacies assemblages that were named as four formations: Wadi Milk Formation, Tagabo Formation, Omdurman Formation, and Shendi Formation. Most of the sediments of the Wadi Milk Formation, especially in areas of low subsidence and relatively high relief at the basin periphery, are deposits of braided river and sandy braided-meandering river systems. The Omdurman Formation is characterized by a lower, fine-grained unit, which originated from meandering rivers, flood plains and lakes, and an upper, coarse-grained unit, which was deposited by sandy braided rivers.