Integrated Geophysical Study to Delineate Mineralised Zones in Southwest Ashanti Belt of Ghana

A.  Ewusi; E.  Adatsi; J.  Seidu

doi:10.4236/gep.2018.67006

A. Ewusi, E. Adatsi, J. Seidu

Abstract: Ground Frequency Domain Electromagnetic (FDEM) and Magnetic surveys were conducted in Southwest of the Ashanti belt in the Western Region of Ghana. The aim was to delineate potential gold mineralisation zones that may occur within the area. The magnetic data processing steps involved analytic signal, first vertical derivative, upward continuation, CET grid analysis as well as depth to basement model (Werner deconvolution). For the electromagnetic survey using the two coil separations (100 m and 150 m) and the multi frequencies (222 Hz, 888 Hz, 3555 Hz), the data in-phase component was processed to produce EM component maps showing the potential mineralisation zones. Lineament analysis using the rose diagram showed that the area is dominated by N-S and NNW-SSE lineaments. The upward continuation and depth to the magnetic source bodies indicated that the magnetic bodies in the study area can be located at depth less than 200 m.

Keywords: Frequency Domain, Electromagnetic Survey, Magnetic Survey, Southwest Ashanti Belt, Ghana

Cite this paper: Ewusi, A. , Adatsi, E. and Seidu, J. (2018) Integrated Geophysical Study to Delineate Mineralised Zones in Southwest Ashanti Belt of Ghana. Journal of Geoscience and Environment Protection, 6, 77-89. doi: 10.4236/gep.2018.67006.

References

[1] Brown, L. and Vearncombe, J. (2014) “Critical Analysis of Successful Gold Exploration Methods”, Applied Earth Science. Transactions of the Institution of Mining and Metallurgy: Section B, 123, 18-24.

[2] Brooks, S.R. and Cameron, G.H. (2009) Banfora Discovery: A Granite Hosted Birimian Gold Deposit in South-Western Burkina Faso, New Generation Gold 2009. In: Yates, K., Ed., Proceedings of Conference of Case Histories of Discovery, Keith Yates and Associates Pty Ltd. and Paydirt Media Pty Ltd., 217-231.

[3] Leube, A., Hirdes, W., Mauer, R. and Kesse, G.O. (1990) The Early Proterozoic Birimian Supergroup of Ghana and Some Aspects of Its Associated Gold Mineralization. Precambrian Research, 46, 139-165. https://doi.org/10.1016/0301-9268(90)90070-7

[4] Sylvester, P.J. and Attoh, K. (1992) Lithostratigraphy and Composition of 2.1 Ga Greenstone Belts of the West African Craton and Their Bearing on Crustal Evolution and the Are-hean-Proterozoic Boundary. The Journal of Geology, 100, 377-393.
https://doi.org/10.1086/629593

[5] Goodwin, A.M. (1991) Precambrian Geology. The Dynamic Evolution of the Continental Crust. Academic Press, London, 666 p.

[6] Milesi, J.P., Feybesse, J.L. and Ledru, P. (1989) Les mineralisations auriferes de l’Afrique de l’Ouest. Leur evolution lithostructurale au Proterozoique inferieur, Carte metallogenique a 1/2 000 000. Chronique de la Recherché Miniere, France, 497, 98.

[7] Hirdes, W., Davis, D.W. and Eisenlohr, B.N. (1992) Reassessment of Proterozoic Granitoid Ages in Ghana on the Basis of U/Pb Zircon and Monazite Dating. Precambrian Research, 56, 89-96.
https://doi.org/10.1016/0301-9268(92)90085-3

[8] Ghana Geological Survey. (2009) Geological Map of Ghana—1:1000000. Geological Survey Department, Accra, Ghana.

[9] Hildenbrand, R., Hinze, W., Keller, G.R., Labson, L. and Roest, W. (2003) New and Unique U.S. Magnetic Database Is Forthcoming. The Leading Edge, 22, 234-244.
https://doi.org/10.1190/1.1885534

[10] Hinze, J., Aiken, C., Brozena, J., Coakley, B., Dater, D., Flanagan, G., Forsberg, R., Hildenbrand, T., Keller, G.R., Kellogg, J., Kucks, R., Li, X., Mainville, A., Morin, R., Pilkington, M., Plouff, D., Ravat, D., Roman, D., Urrutia-Fucugauchi, J., V’eronneau, M., Webring, M. and Winester, D. (2005) New Standards for Reducing Gravity Data. The North American Gravity Database. Geophysics, 70, 25-32. https://doi.org/10.1190/1.1988183

[11] Ku, C. and Sharp, J. (1983) Werner Deconvolution for Automated Magnetic Interpretation and Its Refinement Using Marquart’s Inverse Modelling. Geophysics, 48, 754-774.
https://doi.org/10.1190/1.1441505