Document Type : Original Research Paper

Authors

Faculty of Mining, Petroleum and Geophysics, Shahrood University of Technology, Shahrood, Iran

Abstract

As many gold deposits are associated with sulfide zones, and the direct exploration of gold deposits using the geophysical methods is very difficult due to its low amount in the sub-surface, the direct exploration of sulfide zones by the geophysical electrical resistivity and induced polarization (IP) methods may lead to the indirect exploration of gold deposits. The gold deposit in the Kervian area is located in the Kurdistan shear zone, and is directly related to the sulfide, silica, and carbonate alteration units. After acquiring the resistivity and IP data, 2D modeling of the data is made in order to indirectly identify the gold-bearing zones in the surveyed area. As some of the identified geophysical anomalies indicating the sulfide zones may not be associated with the economic amounts of gold, in order to obtain an exploration pattern for the gold deposit in the studied area, a combination of the geophysical data modeling and interpretation results with the geological information and other exploratory data is used to reduce the uncertainty in identifying the gold-bearing zones in the studied area. Thus, modeling and interpretation of the geophysical data lead to identify the sub-surface anomalies as the locations of possible gold mineralization in the area, and then the drilling points are suggested in the area. Considering the geological studies and chemical analysis of the samples taken from the drilled boreholes crossing some of the geophysical anomalies, we conclude that the geophysical anomalies occurring inside the phyllite and carbonate units in the area can contain an economic amount of gold, and thus are recommended as the top priority for further exploration.

Keywords

[1]. Paterson, N.R. and Hallof, P.G. (1991). Geophysical exploration for gold. In: Foster, R.P. (Ed.) Gold metallogeny and exploration. Springer, doi: 10.1007/978-1-4613-0497-5-12.
[2]. Hannington, M.D., Poulsen, K.H. and Thomsen, J.F. (1999). Volcanogenic gold in the massive sulfide environment. Society of Economic Geologists.
[3]. Doyle, H.A. (1991). Geophysical exploration for gold–A review. Geophysics. 55 (2): 134-146.
[4]. Salmirinne, H. and Turunen, P. (2007). Ground geophysical characteristics of gold targets in the Central Lapland Greenstone Belt. Geological Survey of Finland, Special Paper 44, 209-223.
[5]. Gurin, G.V., Tarasov, A.V., Il’in, Y.T., and Titov, K.V. (2015). Application of the Debye decomposition approach to analysis of induced-polarization profiling data (Julietta gold-silver deposit, Magadan Region). Russian Geology and Geophysics, 56: 1757–1771.
[6]. Sultan, A.S., Mansour, S.A., Monteiro Santos, F., and Helaly, A.S. (2009). Geophysical exploration for gold and associated minerals; case study: Wadi El Beida area, South Eastern Desert, Egypt. Journal of Geophysics and Engineering. 6 (4): 345–356, doi: 10.1088/1742-2132/6/4/002.
[7]. Moon, C., Whateley, M., and Evans, A. (2000). Introduction to Mineral Exploration. Blackwell, Oxford, p. 498.
[8]. Loke, M.H. (2004). Tutorial: 2-D and 3-D electrical imaging surveys. Geotomo Software.
[9]. Edwards, L.S. (1977). A modified pseudo-section for resistivity and induced polarization. Geophysics. 42 (5): 1020-1036.
[10]. Fox, R.C., Hohmann, G.W., Killpack, T.J., and Rijo, L. (1980). Topographic effect of resistivity and induced polarization surveys. Geophysics. 45 (1): 79-93.
[11]. Macinnes, S. and Zonge, K. (1996). Two-dimensional inversion of resistivity and IP data with topography. 102th Annual Northwest Mining Association Convention, Session Geophysics/Geochemistry, Washington.
[12]. Mohajjal, M. (2002). Geological map report, structural and alteration in Kervian area. Geological Survey of Iran (in Persian).
[13]. Ghazanfari, M, Fazli Khani, T. and Abbasi, Z. (2010). Report on public gold exploration in the area of Kervian. Geological Survey of Iran.
[14]. Korei, M.T., Shamsa, M.J., Muhjal, M., and Ishraq, A. (2000). Geological map of 1:20,000 Kervian region in Kurdistan Province. Geological Survey of Iran.