Abstract ref. 262:
Topographically, the southern half of Somalia is comparatively flat, with elevations of < 350 m above sea level. The northern half of the country rises northward to an elevation of 2000 m, where it drops off sharply to the Gulf of Aden. All of Somalia was a peneplain at the end of Paleozoic time. Jurassic limestone then was deposited uniformly over the entire country, but post-Jurassic erosion removed a considerable thickness of these rocks, locally exposing basement. A Cretaceous sea then covered all of Somalia. Transgressions and regressions took place during Cretaceous time, and locally the Cretaceous is disconformable with the overlying Eocene. Marine Eocene sedimentary rocks cover the northern half of Somalia, but are absent in southern Somalia except for a narrow strip along the coast where marine Eocene is present in the subsurface together with marine Oligocene, Miocene and Pliocene, the latter present locally in outcrops. Southern Somalia was subjected to epeirogenic uplift at the end of Cretaceous time and has remained above sea level ever since, except in the coastal areas. The rift faulting of middle and late Tertiary time uplifted the northern half of the country with the result that post-Eocene marine sedimentary rocks are known only along a narrow strip of the coast. There is no evidence of major compressive folding in Somalia, but northeast-southwest-trending anticlines of gentle dip have been mapped in Tertiary rocks in the north and identified in the subsurface in central and southern Somalia. The structures apparently were caused either by rejuvenation of Jurassic fault blocks causing arching of younger sediments, or by leaching of thick underlying evaporites. The most promising region for oil and gas prospecting in Somalia is the Mesozoic shelf and reef area around the Somali embayment and around the Nogal uplift. Secondary prospective oil and gas regions in Somalia are the coastal and offshore marine Tertiary sedimentary rocks. Stratigraphic traps in clastic sedimentary rocks caused by facies changes or overlaps against the uplift regions of Somalia, and monoclinal porosity pinchouts in carbonate sedimentary rocks are other possibilities. Commercial oil and gas deposits are probably present in Somalia. Quinqueloculina inconstans, Epistomina mosquensi, Cristellaria contralis, Lenticulina polonica, E. stellicostata, C. nodosa, E. ornata, Pseudocyclammina sequana, Orbitolina concava O. lenticularis, O. discoidea, Globigerina infracretacea, G. washitaensis, Robulus, Globotruncana, Gumbelina, Globorotalia velascoensis, G. crasia, Anomalina granosa, Cibicides, Sakesaria, Alveolina, Lockhartia tipperi, Nummulites somaliensis and Daviesina danieli are mentioned. 