STRUCTURAL AND THREE-DIMENSIONAL INTERPRETATION OF AEROMAGNETIC ANOMALIES OVER PART OF THE IGNEOUS INTRUSIONS OF KANO STATE, NORTH-CENTRAL NIGERIA
STRUCTURAL AND THREE-DIMENSIONAL INTERPRETATION OF AEROMAGNETIC ANOMALIES OVER PART OF THE IGNEOUS INTRUSIONS OF KANO STATE, NORTH-CENTRAL NIGERIA
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Date
1998-07
Authors
SULEIMAN, MUHAMMED ANKA
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Abstract
An interpretation of aeromagnetic data has been carried out over an area of the
Precambrian to early Palaeozoic basement rocks of Kano State, North-central Nigeria,
between Latitudes 11°00'N to I2°00'N and Longitudes 8°00'E and 9°00'E. The
interpretation covers the areas of igneous intrusions of the basement.
Non-orientational and orientational studies of the lineament features reveal NE-SW
and E-W trends characterizing the area. Statistical analysis using the analytical method of
auto-covariance confirms this result. The residual and second derivative maps emphasize
the shallow features of the area. These features correlate very well with the previous gravity
investigation within the area. The regional field and upward continuation map reflect deep
seated structures in the area and shows the regional structures field have an E-W trend.
This studies show that the area is characterized by NE-SW residuals superimposed on an
E-W treading regional field. Residual anomalies of both high and low amplitude are
recognized on the residual map which are oriented along the interpreted shear zone.
A 3-Dimension interpretational method has been used for the inversion of these
anomalies. A preliminary spectral analysis reveals a shallow depth magnetic horizon of 0.45
to 0.65 km and a deeper layer with depth of 5.2 km to 6.8 km for the rock ensembles. The
results obtained from the inversion method show that the depth to the tops of the modelled
bodies vary from zero to 1.47 km and the depth to the bottom varying from 0.601 km to
8.628 km. With variation in the susceptibility contrast from -0.00120 emu. to +0.0833 emu.
The positive susceptibilities are interpreted to be due to basic igneous intrusions, while the
negative susceptibilities are due to acidic intrusions.
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Description
A THESIS SUBMITTED TO THE POST-GRADUATE SCHOOL
AHMADU BELLO UNIVERSITY, ZARIA, IN PARTIAL
FULFILMENT OF THE REQUIREMENTS FOR THE
AWARD OF MASTER OF SCIENCE DEGREE IN
APPLIED GEOPHYSICS.
Keywords
STRUCTURAL, THREE-DIMENSIONAL, INTERPRETATION, AEROMAGNETIC, ANOMALIES, IGNEOUS, INTRUSIONS, KANO, NORTH-CENTRAL, NIGERIA