COMPARATIVE SEDIMENTOLOGICAL STUDIES OF THE LAFIA, KEANA AND AWE FORMATIONS WITH REFERENCE TO THE AWGU AND ASU RIVER FORMATIONS
COMPARATIVE SEDIMENTOLOGICAL STUDIES OF THE LAFIA, KEANA AND AWE FORMATIONS WITH REFERENCE TO THE AWGU AND ASU RIVER FORMATIONS
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Date
1980-05
Authors
OHIKERE, CHRISTIANA
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Abstract
The area under investigation is part of the Middle
Benue, this region is made up of Cretaceous sediments of
marine to fluvio~deltaic environments,,
Sedimentation in the Benue valley is believed to be
related to the breaking up of South America from Africa,
parting the way for a northward transgression of marine
waters from the great atlantic
The sediments studied are represented by the Lafia,
Keana and Awe Formations respectively and also by the Awgu
and Asu river shales; these sediments are thought to range
in age from Cenomanian to Maastrichtian (Offodile, 1976).
Petrological and sedimentological analysis were carried
out on the data and samples collected from the field work.
The results of sedimentological analysis included granulometric,
heavy and light minerals and clay mineral analysis.
From granulometric analysis, it was observed that the
sandstones were deposited in one as more depositional cycle
(Lafia and Awe Formations) or were reworked after deposition
(Keana Formation) in certain parts of the studied area.
Generally, the sandstones are medium to coarse grained, poorly
sorted, and positively skewed.
Heavy mineral analysis shows the presence of assemblages
of zircon, tourmaline, rutile, staurolite and kyanite, and
opaques (iron oxides?). This indicates an igneous-metamorphic source rock for the sandstones.
The light mineral analysis shows the presence of
quartz and mica, with quartz grains generally being the
most dominant mineral. Their morphology indicates a
relatively strong weathering conditions and short distance
of transportation.
Results from the clay mineral analysis shows the
presence of kaolinite, illite and chlorite in decreasing
order of abundance relatively.
These results prove that these sediments under study
in the Benue basin owe their origin to the Nigerian basement
complex, which is composed of granites, gneisses,
and migmatites. These are found to the north and south
of the mapped area.
Description
PRESENTED TO THE GEOLOGY DEPARTMENT OF AHMADU
BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILMENT
OF THE REQUIREMENTS FOR THE AWARD OF BACHELOR
OF SCIENCE (HONOURS) DEGREE IN GEOLOGY
MAY, 1980
Keywords
COMPARATIVE,, SEDIMENTOLOGICAL,, STUDIES,, LAFIA,, KEANA,, AWE,, FORMATIONS,, REFERENCE,, AWGU,, ASU,, RIVER,, FORMATIONS,