Ewekoro Fm
Period:
Paleogene
Age Interval:
Paleocene
Province:
Dahomey Basin
Type Locality and Naming
The type locality is in the West African Portland Cement Quarry about 40 miles north of Lagos (Whiteman, 1982). According to Nwajide (1982) the type locality is in Ewekoro, between Itori and Papa-Alanto and the type section is 145m thick from the GSN Borehole Nos. 1582 and 1583 drilled at Akinsinde and near Itori.
References: Reyment, 1965; Adeleye, 1975; Kogbe,1976; Dessauvagie, 1975; Petters, 1978; Offodile, 1980; Whiteman, 1982; Benkhelil, 1989; Okosun, 1992; Guiraud, 1993; Akande et al., 1998; Zaborski et al., 1998; Jauro et al., 2007; Obaje, 2009; Nwajide, 2013
Lithology and Thickness
Ewekoro Formation is a thin shelly limestone, in places glauconitic, which becomes sandy near the base. Is a lateral equivalent of the Imo Shale Fm. The surface of the limestone is pot-holed, water-worn and scoured (Whiteman, 1982). According to Whiteman (1982) the formation is about 40ft thick at the type locality but according to Nwajide (1982) the type section is about 145m thick.
Lithology Pattern:
Limestone
Relationships and Distribution
Lower contact
Upper contact
Unconformably underlies the Akinbo Fm
Regional extent
The formation is traceable for 320km continuously from east Accra, eastwards through the whole of the Dahomey Basin (Enu and Adegoke, 1988).
GeoJSON
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Fossils
Echinoids, Gastropods, nautiloids, pelecypods, ostracods
Age
early Paleocene (unconformity at base => left schematic gap of Lower Selandian)
Age Span:
Beginning stage:
Danian
Fraction up in beginning stage:
0.0
Beginning date (Ma):
66.04
Ending stage:
Selandian
Fraction up in the ending stage:
0.0
Ending date (Ma):
61.66
Depositional setting
Marine setting, under tropical littoral to neritic conditions (Whiteman, 1982).
Depositional pattern:
Additional Information
Compiler:
Enam O. Obiosio, Solomon Joshua Avong and Henry Nasir Suleiman (2024)- Stratigraphic Lexicon compiled from the following books:Nigeria: Its Petroleum Geology, Resources and Potential, by Arthur Whiteman, 1982; (Volume 1) Published by Graham and Trotman Ltd.A review of the Cretaceous System in Nigeria by P. M. Zaborski (1998) In Africa Geoscience Review, Vol.5, No.4, pp385-483
Geology and Mineral Resources of Nigeria by Nuhu George Obaje, Published by Springer-Verlag Berlin Heidelberg 2009; http://www.springer.com/series/772
Geology of Nigeria Sedimentary Basins, Nwajide C. S., 2013; Published by CSS Bookshops Limited, Lagos Nigeria.