8th International Nannoplankton Association Conference


[Abstracts] [A] [B] [C] [D] [E] [F] [G] [H] [I] [J] [K] [L] [M] [N] [O] [P] [Q] [R] [S] [T] [U] [V] [W] [X] [Y] [Z]

Saliu Maama:
Geology of Ghana with emphasis on Recent deposits

Ghana, a W African country, can conveniently be divided into five main geological domains on the basis of age, tectonics and lithological characteristics of the supracrustal rocks. These are: (i) the western unit, which lies at the eastern margin of the Precambrian W African Craton; (ii) the southeastern unit, which is in the SE of Ghana, belonging to the Precambrian mobile belt; (iii) the flat lying central unit made up mainly of the sediments of the Voltain system; (iv) the coastal sedimentary basin; and (v) Tertiary to Recent deposits. The coastal basin and Tertiary to Recent deposit occupy the coastal region of the country. They consist of five sedimentary basins stretching from the extreme SE to the extreme SW corners of the country. The five coastal sedimentary basins are: (1) Keta Basin; (2) the Accraian Series; (3) the Amissian Formation; (4) the Sekondian Series; and (5) the Apollonian (Tano Basin) Formation. The Keta Basin, which lies at the extreme SE corner of the country, consists of sand, gravel, siltstones, shales, and clays with layers of fossiliferous limestone. Three onshore and one offshore oil wells have so far been drilled in the basin. Hydrocarbon shows were recorded in two of them. The Accraian Series consists of quartz grits, shales and mudstone. The fossils found in this series were attributed to the Middle Devonian on the basis of close resemblance to N America faunas of that age. Examples of such faunal assemblages are species of terbratuloid, e.g. Discinisca sp., Pleurodapis sp., Tentaculites sp., etc. The Amissian consists of a series of interbedded, soft, pebbly grits, conglomerates, micaceous sandstone and shales. The Sekondi Series consists mainly of sandstones and shales with conglomerates, pebble beds, grits and mudstones resting with major unconformity on a complex of granites, gneisses and schists. Six formations are recognised in this series, with some being fossiliferous, others not. They range in age from Devonian to Cretaceous. The Takoradi Shales, being one of the formations, has traces of oil and is fossiliferous with lamellibrachs, brachiopods and gastropods. Finally, the Apollonian Formation, which comprises Cretaceous-Eocene marine sedimentary rocks, occurs in the eastern portion of a crescent-shaped basin along the coast of the Atlantic Ocean and occupy the SW corner of the country. The only prominent stratigraphic marker of the formation is a series of thin, highly fossiliferous limestones, known in the geological literature as Naulilimestone.


[Registration and Accomodation Form]
[First Circular and Pre-Registration]
[Second Circular]

 [Division of Micropalaeontology] [Department of Geosciences] [Bremen University]

 [INA Europe]  

Copyright © 2000, most recent revision July 25, 2000

Tania Hildebrand-Habel (