Cenozoic

Cretaceous

Neoproterozoic

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Kerri-Kerri Formation

Kerri-Kerri Fm

Period:

Paleogene

Age Interval:

Paleocene (Danian - Thanetian)

Province:
Benue Trough North -Gongola Arm, Bornu Basin (SW. Chad Basin)

Type Locality and Naming

Typical sections are exposed in Gombe Aba, Duku (not Dukul) and Alkaleri.

Synonym: Ako Sandstones (Baber et al., 1954)

References: Baber et al., 1954; Carter et al., 1963; Obaje, 2009; Nwajide, 2013

[Fig 1. Stratigraphic successions in the Benue Trough and the Nigerian sector of the Chad Basin]

Lithology and Thickness

The lithology is made up of whitish grey sandstones, siltstones, and massive claystones with the claystones dominating the lithology in most places. The clays of the Kerri-Kerri are usually gritty and massive and their lithology suggest a lacustrine environment. The sandstones of the Kerri-Kerri are often cross-bedded ferruginised sandstone and gritty clay with colors varying from reddish brown to grey (Obaje, 2009), and lignites occur near the base of the formation. Plant remains are prevalent. The sequence is often capped with thick laterite which may be either oolitic or vesicular in texture. Thickness can range from 200 to 600 meters; and was estimated by Carter et al (1963) as around 130m thick for the Northern Benue Trough.

Lithology Pattern:

Sandy claystone

Relationships and Distribution

Lower contact

Shown as unconformably (with gap interval) above the Gombe Fm (Gombe Sandstone Fm)

Upper contact

No contact, or Overlain by the Chad Fm.

Regional extent

Benue Trough North - Gongola Arm. In Lake Chad region, where this Gongola arm continues under the later lacustrine deposits, an outcrop section was reported North of Maiduguri around Lake Chad through to along the boundary with the Benue Trough near Abakire and Ngelzarma (Carter et al., 1963). This formation was not encountered in any of the exploratory oil wells drilled by the Nigerian National Petroleum Cooperation (NNPC) since drilling was concentrated north of Maiduguri around Lake Chad. It occurs in the south of the basin along the boundary with the Benue Trough (Obaje, 2009).

GeoJSON

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Fossils

Pollen and Spores, Plant fossils

Age

Paleocene (but indicated as not including earliest Paleocene). The Paleocene age was suggested based on palynomorphs recovered from coals (swampy conditions during deposition) obtained from boreholes by Shell-BP Petroleum Development Company of Nigeria Limited, which same Shell-BP now considers doubtful.

Age Span:

Beginning stage:

Danian

Fraction up in beginning stage:

0.2

Beginning date (Ma):

65.16

Ending stage:

Thanetian

Fraction up in the ending stage:

1.0

Ending date (Ma):

56.00

Depositional setting

Continental depositional environment which contains sandstones are typically fluvial in origin, indicating deposition in river and floodplain environments. Lacustrine–deltaic depositional environment (Carter et al., 1963), which showed that sedimentation was in river channels, floodplains, and associated settings Consists of two cyclothems of coarsening upward sequence in the type section (Nwajide, 2013).

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.