STRUCTURAL INTERPRETATION OF GRAVITY AND AEROMAGNETIC ANOMALIES OVER SOKOTO BASIN, NORTHWESTERN NIGERIA.

Simple item page
dc.contributor.authorMARIUS, NNANNA UMEGO
dc.date.accessioned2014-09-08T08:43:00Z
dc.date.available2014-09-08T08:43:00Z
dc.date.issued1990-03
dc.descriptionA THESIS SUBMITTED TO THE POSTGRADUATE SCHOOL AHMADU BELLO UNIVERSITY, ZARIA, IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN GEOPHYSICS. DEPARTMENT OF PHYSICS FACULTY OF SCIENCE AHMADU BELLO UNIVERSITY ZARIA, NIGERIA. MARCH, 1990.en_US
dc.description.abstractThe first composite magnetic anomaly map of the Sokoto Basin has been compiled at a scale of 1:3,000,000 from a total of thirty Geological Survey of Nigeria aeromagnetlc maps. The composite map revealed major structures in the Precambrian basement beneath the sediments, and delineated areas for more detailed investigations. A system of large scale NE-SW and NW-SE trending magnetic lineations were also revealed, and these have been interpreted to be part of the continent-wide conjugate strike-slip fault system of probable tectonic origin. The magnetic lineations and intrusive activities are concentrated along three prominent linear belts which probably represent preexisting zones of crustal weakness in the continental crust. The significance of these zones with regard to mineralization and seismicity have been highlighted. A magnetic depth to basement analysis has revealed that the basement surface is generally shallow, and attain a maximum depth of 1.8 km at the extreme NW corner of the basin. The regional dip is gentle, and measured 0.4 in the northwestern direction.Also gravity data were collected along all motorable roads in the basin and in parts of the adjoining basement block of northern Nigeria. Threedimensional interpretation of the gravity data led to the following conclusions: (1) The isolated Older Granite outcrops around Gusau coalesce into one big (ix) pluton just beneath the ground surface and extend to a depth of 4.3 km with steeply dipping contacts which suggest a magmatic origin for these granite bodies. (2) The metasediments of the Anka Schist Belt are generally outward dipping, and attain a general thickness of 2.5 km, terminating in a characteristic flat base. This simple structural style suggests that the sequence was probably affected by only one tectonic event which left a N-S trending structural grain on these rock units. (3) A number of depressions in the subsurface basement rocks have been revealed where sedimentary thicknesses range from 0.5 to 1.0 km. Over the basin, both gravity and magnetic data have revealed an irregular basement floor resulting from gentle folding of the basement rocks along a general N-S axis, at wavelength scales of roughly 100 km and amplitudes of only a few hundred meters. Several sediment-filled troughs and depressions on the basement surface have been revealed which form targets for groundwater exploration. The absence of major faulting even at the sediment-basement boundary tend to suggest that this southeastern sector of the Iullemmeden Basin probably originated from gentle epeirogenic warpings in contrast to the western and northeastern partsen_US
dc.identifier.urihttp://hdl.handle.net/123456789/5282
dc.language.isoenen_US
dc.subjectSTRUCTURAL,en_US
dc.subjectINTERPRETATION,en_US
dc.subjectGRAVITY,en_US
dc.subjectAEROMAGNETIC,en_US
dc.subjectANOMALIES,en_US
dc.subjectSOKOTO BASIN,en_US
dc.subjectNORTHWESTERN NIGERIA.en_US
dc.titleSTRUCTURAL INTERPRETATION OF GRAVITY AND AEROMAGNETIC ANOMALIES OVER SOKOTO BASIN, NORTHWESTERN NIGERIA.en_US
dc.typeThesisen_US
Files
Original bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
STRUCTURAL INTERPRETATION OF GRAVITY AND AEROMAGNETIC ANOMALIES OVER SOKOTO BASIN, NORTHWESTERN NIGERIA..pdf
Size:
8.54 MB
Format:
Adobe Portable Document Format
Description:
Download
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.58 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
SCIENCE