Geology of the Al-Khums area northwestern Libya with emphasis on the stratigraphy and biostratigraphy of the Al-Khums formation

<p>"The dissertation represents a geologic study of an area bordering the Mediterranean Sea in northwestern Libya. About 1200 km² were mapped and 28 stratigraphic sections were prepared.</p> <p>The bedrock consists of 16 stratigraphic units of Mesozoic and Cenozoic age having a combined maximum thickness of about 750 meters. The oldest unit exposed, the Abu Shaybah Formation, is a redbed sequence of Triassic and Jurassic age. These beds are unconformably separated from Cretaceous carbonates (Garian Limestone, Ain Tobi Formation, and Gezzar Dolomite). These units in turn are overlain by the Miocene Al-Khums Formation. Younger Quaternary units consist of nearshore marine sandstones, wadi deposits, loess, sebkha deposits, and caliche which is widespread and often obscures the bedrock.</p> <p>The structure in the area is relatively simple being dominated by a broad gentle anticline. A structure contour map drawn on the Cretaceous-Miocene unconformity illustrates the pronounced relief developed prior to the encroachment of the Miocene sea.</p> <p>Three foraminiferal assemblage zones were established in the Al-Khums Formation: <em>Elphidium crispum</em>, <em>,</em> and <em>Lentioulina</em> sp. Range charts for the species in these zones have been compiled. The Formation is dated as middle Miocene (Vindobonian Stage).</p> <p>The Al-Khums Formation was deposited under shallow water marine conditions. Reef patches developed near the former shoreline. Lithologic and paleontologic criteria indicate the formation represents two major sea transgressions separated by a regressive cycle. A major withdrawal of the sea occurred in Late Miocene; this is likely coincident with the widespread development of evaporites in the Mediterranean Sea"--Abstract, pages ii-iii.</p>

Name thesis:degree_name

Ph. D. in Geology

Grantor

University of Missouri--Rolla

Year dc:date.available

2016

Author dc:creator

• Salem, Mostafa Juma

• Geology

Repository record dc:identifier

https://scholarsmine.mst.edu/doctoral_dissertations/368

OAI identifier oai:identifier

oai:scholarsmine.mst.edu:doctoral_dissertations-1370