Qualitative Interpretation Of Aerogravity And Aeromagnetic Survey Data Over The South Western Part Of The Volta River Basin Of Ghana
George Hinson, Aboagye Menyeh, David Dotse Wemegah
Keywords: Aeromagnetic, Aerogravity data, Qualitative,interpretation, Volta River basin, Anomalies, Birimian, Tarkwaian, Voltaian Supergroup, Eburnean plutonic suite.
Abstract: The study area (South western part of Volta River Basin of Ghana), covering an area of 8570 km2, which is one-eleventh the area of the Volta River basin of Ghana, has been subjected to numerous academic research works but geophysical survey works because of virtual perceptive reasons. It is now believed to overly mineral-rich geological structures, hence, the use of magnetic and gravity survey methods to bring out these mineral-rich geological structures.Geographically, it (study area) is located at the south western part of the Voltaian basin at latitudes 07o 00 N and 08o 00 N and longitudes 02o 00 W and 01o 00 W respectively. Airborne gravity and magnetic survey methods were employed in the data collection. The field data correction and error reduction were applied to the two raw data on the field after which, Geosoft Oasis Montaj 7.01, Encom Profile Analysis (P.A) 11 and 13, Model Vision 12 and ArcGIS 10.0 were used to process, enhance (e.g. reduce to pole at low latitude, first vertical derivative etc.), model the reduced and corrected airborne magnetic data, and also, to produce maps from them (data). Low-to-moderate-to-high gravity and magnetic anomalies were obtained in the complete Bouguer anomaly (CBA) and total magnetic intensity (TMI) reduced to pole at low latitude with many of these anomalies trending NE-SW by which the Birimian Metasediments and Metavolcanics can be said to be part of the causative structures of these anomalies with cross-cut NW-SE faults. From the quantitative point of view, the intrusive granitic bodies of the study area have a mean depth location of 1.7 km, while the isolated anomaly is located at a depth of 1.4 km (computed from Euler deconvolution). The NE-SW trending anomalies show the trend direction of their causative structures which are the basement rocks and the basinal intrusive bodies.
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