Cenozoic

Cretaceous

Neoproterozoic

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Owelli Sandstone Formation

Owelli Sandstone Fm

Period:

Cretaceous

Age Interval:

Campanian – Maastrichtian

Province:
Anambra Basin

Type Locality and Naming

The Nkporo Gr includes an upward succession of the Nkporo Shales Fm (or equivalent), Owelli Sandstone Fm and Enugu Fm (or equivalent). Type section located near the village of Owelli on the old road from Enugu to Awgu (Reyment, 1965; Nwajide, 2013).

Synonym: Owelli Fm

References: Reyment, 1965; Adeleye, 1975; Dessauvagie, 1975; Kogbe, 1976; 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

Owelli Fm: consists of massive, hard ferruginous sandstones. They are prominently cross-bedded in places and are generally medium to coarse-grained and contain pebble bands. Occasionally thin silty or argillaceous bands are present (Whiteman, 1982). The Owelli Sandstone is in general about 1,500ft thick (Simpson, 1954). There are also interbeds of marine, dark grey, micaceous, pyritic, calcareous, and occasionally glauconitic shales (Nwajide, 2013).

Lithology Pattern:

Sandstone

Relationships and Distribution

Lower contact

Overlies the Nkporo Shale Fm.

Upper contact

Overlain by the Enugu Fm

Regional extent

Anambra Basin

GeoJSON

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Fossils

Age

mid-Campanian

Age Span:

Beginning stage:

Campanian

Fraction up in beginning stage:

0.5

Beginning date (Ma):

77.91

Ending stage:

Campanian

Fraction up in the ending stage:

0.65

Ending date (Ma):

76.19

Depositional setting

Marine environment characterized by a brackish lagoonal and lower delta plain setting (Nuhu, 1992; Petters, 1995). Campanian transgression to Maastrichtian withdrawal (regression)

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.