Document Type : Original Research Paper
- Ghazal Janghorban 1
- Seyed Mohammad Abtahi Forooshani 1
- Keytash Moshtaghian 1
- Hooshang Asadi Harooni 2
- Hamzeh Sadeghi Sorkhani 1
- Mohammad Hajheidari 1
1 Department of Exploration, Faculty of Mining Engineering, Isfahan University of Technology, Isfahan, Iran
2 Assistant Professor, Department of Mining Engineering, Isfahan University of Technology, Isfahan, Iran
Kuh-e Lakht epithermal gold index is located on Urumieh-Dokhtar Volcanic Belt in Isfahan province. Geological studies indicate the presence of an epithermal gold mineralization system in the area. The geophysical exploration in the area includes magnetometry, resistivity, and induced polarization surveys. Then, we implemented Li and Oldenburg algorithm for 3D inversion of the magnetic data. The depth of the largest estimated magnetic susceptibility obtained from data inversion coincides with the average depth of the magnetic sources obtained from Euler deconvolution. Furthermore, we compared the estimated 2D resistivity and electrical changeability models and the estimated magnetic susceptibility. The comparison denotes the correlation of the estimated magnetic susceptibility variations with the reduction of resistivity, high electrical chargeability, and alteration zones. Combining the estimated magnetic susceptibility model with the geochemical analysis of the exploratory boreholes in the area indicates that the mineralization often occurred at the maximum variation of the magnetic susceptibility. Nonetheless, the results indicate the possibility of mineralization along the zones with large magnetic susceptibility variations.
Abedi, M., Gholami, A., Norouzi, G. H., and Fathianpour, N., 2013. Fast inversion of magnetic data using Lanczos bidiagonalization method, Journal of Applied Geophysics. Elsevier B.V., 90, pp. 126–137. doi: 10.1016/j.jappgeo.2013.01.008.
Baranov, V., 1957. A new method for interpretation of aeromagnetic maps: pseudo-gravimetric anomalies, Geophysics. Society of Exploration Geophysicists, 22(2), pp. 359–382.
Baranov, V., and Naudy, H., 1964. Numerical calculation of the formula of reduction to the magnetic pole, Geophysics. Society of Exploration Geophysicists, 29(1), pp. 67–79.
Eldosouky, A. M., Pham, L. T., Mohmed, H., and Pradhan, B., 2020. A comparative study of THG, AS, TA, Theta, TDX and LTHG techniques for improving source boundaries detection of magnetic data using synthetic models: A case study from G. Um Monqul, North Eastern Desert, Egypt, Journal of African Earth Sciences, 170, 103940.
Hedenquist, J. W., Arribas, A., and Gonzalez-Urien, E., 2000. Exploration for epithermal gold deposits, Reviews in Economic Geology, 13(2), pp. 45–77.
Hoschke, T., 2011. Geophysical signatures of copper-gold porphyry and epithermal gold deposits, and implications for exploration. CSIRO.
Hoschke, T., and Parks, J., 2003. Geophysical Exploration of the Pajingo Epithermal System, ASEG Extended Abstracts. CSIRO, 2003(2), pp. 1–4.
Irvine, R. J., and Smith, M. J., 1990. Geophysical exploration for epithermal gold deposits, Journal of Geochemical exploration. Elsevier, 36(1–3), pp. 375–412.
Kigai, I. N., 2020. Formation Environments of Metasomatites and Ores of the Epithermal Gold–silver Deposits, Geology of Ore Deposits. 62, pp. 432–437.
Li, Y., and Oldenburg, D. W., 1996. 3-D inversion of magnetic data, Geophysics. Society of Exploration Geophysicists, 61(2), pp. 394–408.
Li, Y., and Oldenburg, D. W., 2003. Fast inversion of large-scale magnetic data using wavelet transforms and a logarithmic barrier method, Geophysical Journal International. Blackwell Publishing Ltd Oxford, UK, 152(2), pp. 251–265.
Locke, C. A., Cassidy, J., Harris, M. C., Kirkby, A., Mauk, J. L., Morrell, A. E., Rowland, J. V., and Smith, N., 2007. Geophysical characteristics of the southern Coromandel Volcanic Zone, New Zealand, and associated epithermal deposits, ASEG Extended Abstracts. Taylor & Francis, 2007(1), pp. 1–5.
Maden, N., and Akaryalı, E., 2015. Gamma ray spectrometry for recognition of hydrothermal alteration zones related to a low sulfidation epithermal gold mineralization (eastern Pontides, NE Türkiye), Journal of Applied Geophysics. Elsevier, 122, pp. 74–85.
Meng, Z., 2017. New potential data inversion to obtain the geological structures with a Laplacian kernel, International Geophysical Conference, Qingdao, China, 17-20 April 2017, doi.org/10.1190/IGC2017-068.
Menke, W., 2018. Geophysical data analysis: Discrete inverse theory. Academic press.
Modriniak, N., and Marsden, E., 1938. Experiments in geophysical survey in New Zealand. Department of Scientific and Industrial Research.
Okada, K., 2000. Geophysical exploration at Hishikari gold mine, Kagoshima, Japan, The Leading Edge. Society of Exploration Geophysicists, 19(7), pp. 744–750.
Oldenburg, D. W., and Li, Y., 1994. Inversion of induced polarization data, Geophysics. Society of Exploration Geophysicists, 59(9), pp. 1327–1341.
Oldenburg, D. W., and Pratt, D. A., 2007. Geophysical Inversion for Mineral Exploration : a Decade of Progress in Theory and Practice, Proceedings of Exploration ’07: Fifth Decennial International Conference on Mineral Exploration, (2003), pp. 61–99.
Oruç, B., and Selim, H. H., 2011. Interpretation of magnetic data in the Sinop area of Mid Black Sea, Turkey, using tilt derivative, Euler deconvolution, and discrete wavelet transform, Journal of Applied Geophysics. Elsevier B.V., 74(4), pp. 194–204. doi: 10.1016/j.jappgeo.2011.05.007.
Ransome, F. L., 1907. The association of alunite with gold in the Goldfield district, Nevada, Economic Geology. Society of Economic Geologists, 2(7), pp. 667–692.
Ravat, D., 1996. Analysis of the Euler method and its applicability in environmental magnetic investigations, Journal of Environmental and Engineering Geophysics. Society of Exploration Geophysicists, 1(3), pp. 229–238.
Ren, Z., and Kalscheuer, T., 2020. Uncertainty and Resolution Analysis of 2D and 3D Inversion Models Computed from Geophysical Electromagnetic Data, Surveys in Geophysics, 41, pp. 47–112, doi.org/10.1007/s10712-019-09567-3.
Reynolds, J. M., 2011. An Introduction to Applied and Environmental Geophysics, Preview. doi: 10.1071/pvv2011n155other.
Spichak, V. V., 2020. Modern Methods for Joint Analysis and Inversion of Geophysical Data, Russian Geology and Geophysics, 61 (3), pp. 341–357.doi.org/10.15372/RGG2019092.
Taylor, B. E., 2007. Epithermal gold deposits, Mineral deposits of Canada: a synthesis of major deposit-types, district metallogeny, the evolution of geological provinces, and exploration methods: Geological Association of Canada, Mineral Deposits Division, Special Publication, 5, pp. 113–139.
Thompson, D. T., 1982. EULDPH: A new technique for making computer-assisted depth estimates from magnetic data, Geophysics. Society of Exploration Geophysicists, 47(1), pp. 31–37.
Usman, N., 2018. Automatic interpretation ofmagnetic data usingeulerdeconvolution with modified algorithm, Ph.D. thesis, Universiti Sains Malaysia.
Wang, L., Qin, K., Song, G., and Li, G., 2019. A review of intermediate sulfidation epithermal deposits and subclassification, Ore Geology Reviews, 107, pp. 434-456