SEDIMENTOLOGICAL ANALYSIS OF THE MAIN FACIES’ ASSOCIATION OF THE KABAW FORMATION, NW LIBY

The Early Cretaceous Kabaw Formation exposed in western Jabal Nafusah NW Libya, extends along the escarpment from eastern Jadu to Tunisia, it is unconformably overlies the Shakshuk Formation, and is unconformably overlain by Kiklah Formation, this study dealing with sedimentological analysis of the outcrops of the Formation in western Jabal Nafusah. The Kabaw Formation Neocomian (Early Cretaceous) comprises essentially sandstone locally containing thin horizon rich in vertebrate fossils, in this study the vertebrate fauna provides new stratigraphical evidence, they strongly support a Neocomian age for the Kabaw Formation. The sand grains of the Kabaw Formation show several mechanical patterns similar to those observed on sand grains from the Kiklah and Chameau Mort Formations; this may indicate a mixed continental environment where alluvial and Aeolian conditions alternated. The Kabaw Formation consists of yellowish-gray, friable, fine to medium grained, cross-bedded sandstones, the sediments consist a silicified wood fragment, fish teeth, turtle shells and crocodile teeth were.Owing to the lack of a detailed study of facies associations and depositional environments for Kabaw formation in the past, so i studied formation detailed study. After a detailed description of sedimentary rocks for Kabaw Formation in my study area, it description on the basis of variations in the grain size, color, bedding, mineral composition, texture, fossils and sedimentary structures, it has been identified and divided sedimentary rocks for Kabaw Formation to six facies associations, each representing a particular environment of deposition, and discuss the parameters controlling the deposition of this sediment, these were deposited within four main depositional environments: Braided River, Meandering River, Eolian Dune, and lacustrine depositional environments. The vertical and lateral correlation of facies associations characterized by a progressive change from proximal to deeper depositional setting which are cleaily observed from sand grain size, sedimentary structures and biogenic content. Detailed petrographic analysis of the Kabaw Formation has revealed the importance of variations in mineral composition, and classify the sandstones and source rocks, and studied sediment to improve our understanding of the diagenetic history and its relationships with depositional, assist at interpretation of the sedimentary facies and depositional environment, examine the local and regional plate-tectonic setting of the Kabaw Formation and the Ghadames Basin.