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Depositional Systems and Stratigraphy of Paleozoic and Lower Mesozoic Rocks in Outcrop, Tassili Region, Southwest Algeria

HERTIG, S. P., ARCO International Oil and Gas Company, Plano, TX, R. S. TYE, ARCO Oil and Gas Company, Plano, TX, D. Q. COFFIELD, and J. V. C. HOWES, ARCO International Oil and Gas Company, Plano, TX, and S. FERHATI, Sonatrach, Division Exploration, Algiers, Algeria

Paleozoic to Lower Mesozoic strata of the southeastern Algerian Tassili are traditionally subdivided by regionally extensive unconformities such as the Pan African, Taconic, Caledonian, and Hercynian. Using outcrop data from southeastern Algeria, this classic approach is modified by reinterpreting the genesis of these unconformities and rock sequences. Five prominent sequences, defined within the Paleozoic and lower Mesozoic section, usually consist of a succession of lowstand, transgressive, and highstand system tracts separated by sequence boundaries or transgressive surfaces. The Pan-African, Taconic, Caledonian, and Hercynian unconformities are sequence boundaries. Important sequence boundaries also occur within the Ordovician and Silurian sections. These sequences correlate with ubsurface data in the Illizi basin and provide a framework for renewed exploration in the subsurface of the Algerian Sahara, where more than 30 billion bbl of recoverable oil and oil equivalent have been generated and trapped.


AAPG Search and Discovery Article #91007© 1991 AAPG International Conference, London, England, September 29-October 2, 1991 (2009)