...Leon Visse Abstract The so-called upper and lower phosphate beds of the Onk massif, Algeria, represent one bed, whose northern extension was displaced by a pre-Miocene fault. Africa Algeria economic geology faults North Africa Onk massif phosphates GeoRef, Copyright 2004, American...

... — South Taimyr, 10 — numbers of studied provinces and sections of volcanogenic series; 11 — a ) meymechites, b ) picrite porphyries and picrite basalts. Formations in provinces (encircled numbers): 1 — Maimecha-Kotui: mj — Maimecha, dl — Del’kan, tv — Tyvankit, onk — Onkuchan, prb — Pravaya...

... on, transgressions came from the north and northeast ( Hecht et al ., 1964 ; Hoffman-Rothe, 1966 ). The major positive feature of the central Sahara, the Hoggar massif ( Fig. 1 ), is a large inlier of Precambrian igneous and metamorphic rocks, exposed by erosion and surrounded by a plateau of Paleozoic strata...

... to the great regional geologic and physiographic basin south of the Eglab Massif in interior French West Africa, was in 1952 and subsequent reports re-labeled as the “West Sahara Basin” and later the “Taoudeni Basin” to avoid confusion with the Saharan portion of Algeria or “North Sahara area...

... for oil, but also none of which has shown any very attractive indications of oil. The interior of the northern half of Africa contains an extensive development of marine Paleozoic sediments in various basins surrounding, in a general way, the Ahaggar, Tibesti, and other associated Precambrian massifs...