A THREE-DIMENSIONAL INTERPRETATION OF THE BOUGUER ANOMALIES OVER THE MINNA BATHOLITH IN NIGER STATE
A THREE-DIMENSIONAL INTERPRETATION OF THE BOUGUER ANOMALIES OVER THE MINNA BATHOLITH IN NIGER STATE
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Date
1985-07
Authors
UDENSI, EMMANUEL EMEKA
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Abstract
ABSTRACT
A gravity survey over the Older Granite intrusion of the Minna Area in Nigeria shows that the area is characterized by a prominent residual gravity low of -21
mGal relative to a northeast-southwest trending regional anomaly. Three-dimensional modelling of the residual gravity indicates that the floor of the Older Granite
suite is, in general, located at a depth of 5 km, and that the walls of the suite may be inward dipping Prominent plugs extend to 8-14 km depth locally in three regions.
The general size of the modelled bodies and pattern of
the anomalies suggest that the granite suite is a batholith which was magmatically emplaced with the three plugs acting as conduits for the ascent of magma. The modelling also suggests that the contacts of
the granite suite with the flanking Birnin Gwari and Kushaka Schists Formations are steep and that the maximum thicknesses of these formations are 11 and 6.5 km
respectively with parts of the Kushaka formation underlain by the granite suite below depths of 1.8 km.
Description
A THESIS Submitted in partial fulfilment of the requirements for the degree of Master of Science, Applied Geophysics. Department of physics Ahmadu Bello University,
ZARIA
Keywords
THREE-DIMENSIONAL,, INTERPRETATION,, BOUGUER,, ANOMALIES,, MINNA,, BATHOLITH,, NIGER STATE.