The study of magnetic structures using aeromagnetic data and investigating their relationship with porphyry copper mineralization in the Shahr-e Babak, Kerman province, Iran

Document Type : Research Article

Authors

1 Ph.D. Student in Mineral Exploration, Amir Kabir University, Tehran, Iran

2 Professor, Department of Mineral Exploration, Faculty of Mine, Amir Kabir university, Tehran, Iran

3 Ph.D. Student in Mineral Exploration, Tehran university, Tehran, Iran

4 Khavaran Kavosh Zahid Consulting Engineers Co.

Abstract

Studied area is located in Kerman province, Iran. This area belongs to the Urumia-Dokhtar magmatic arc (UDMA) zone. Several porphyry copper deposits were known in this magmatic arc. UDMA is marked by voluminous Tertiary volcanic sequences of up to 3000 m thickness. It seemed that these Cu occurrences are related to structures, especially major and main faults.
In this study, magnetic structures were extracted by using the aeromagnetic data. This data was extracted by Atomic Energy Organization of Iran (AEOI) during 1977 and 1978. The flight lines distance and the sensor altitude were about 500 and 120 m, respectively. Airborne magnetic method is among the most efficient geophysical techniques for the detection of buried anomalies.
In the first step, total magnetic intensity map was prepared and reduction to pole transformation was done on it. Reduction to the pole (RTP) is a standard part of magnetic data processing method, especially for large-scale mapping. RTP operation can transform a magnetic anomaly caused by an arbitrary source into the anomaly that the same source would produce if it is located at the pole and magnetized by induction only. Interpretation of magnetic data can further be helped by RTP in order to remove the influence of magnetic latitude on the anomalies, which is significant for anomalies caused by crust. Most of the studied areas are covered by mafic volcanic rocks. These rocks produce moderate to high magnetic anomalies. In some parts, the effect of demagnetization can be observed in these rocks because of the spread of alteration in this area. A low magnetic anomaly is observed in the northern part of the studied area related to sedimentary rocks in this area. In the next step, body magnetic anomalies were extracted from reduction to pole map. A tilt angle filter used to extract magnetic lineaments was applied to the reduction to pole data. Upward continuation filter was implemented at 200 m, 500 m and 1000 m on the tilt angle map and magnetic lineaments were extracted from tilt angle maps. Several magnetic lineaments and magnetic bodies were extracted from magnetic maps (tilt angle maps and reduction to pole maps). There is good correspondence between magnetic structures and copper occurrences. The P-A curve confirms this result. 

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اصفهانی نژاد، م.، رحیمی، م.، 1379، تهیه نقشه پتانسیل مواد معدنی در گستره برگه 1:100000 شهربابک با بهره‌گیری از سیستم اطلاعات جغرافیایی (GIS): گزارش سازمان زمین‌شناسی کشور.
مقدم، م.، فنایی خیرآباد، غ.، میرزایی، س.، عابدی، م.، 1398، تفسیر داده‌های مغناطیس هوایی به‌منظور تخمین عمق پی‌سنگ مغناطیسی و گسل‌های پنهان در منطقه بصیران، خراسان جنوبی: فصلنامه زمین‌شناسی کاربردی، 51، 111-128.
Anderson, E. D., Hitzman, M. W., Monecke, T., Bedrosian, P. A., Shah, A. K., and Kelley, K. D., 2013, Geological analysis of aeromagnetic data from southwestern Alaska: Implications for exploration in the area of the Pebble porphyry Cu-Au-Mo deposit: Economic Geology, 108, 421-436.
Anderson, E. D., Zhou, W., Li, Y. G., Hitzman, M. W., Monecke, T., Lang, J. R., and Kelley, K. D., 2014, Three-dimensional distribution of igneous rocks near the Pebble porphyry Cu-Au-Mo deposit in southwestern Alaska: Constraints from regional-scale aeromagnetic data: Geophysics, 79, B63-B79.
Baranov, V., and Naudy, H., 1964, Numerical calculation of the formula of reduction to the magnetic pole: Geophysics, 29, 67-79.
Behn, G., Camus, F., Carrasco, P., and Ware, H., 2001, Aeromagnetic signature of porphyry copper systems in Northern Chile and its geologic implications: Economic Geology, 96(2), 239–248.
 
De Oliveira, D. C., Dall’Agnol, R., Corrêa da Silva, J. B., and Costa de Almeida, J. A., 2008, Gravimetric, radiometric, and magnetic susceptibility study of the Paleoproterozoic Redenção and Bannach plutons, eastern Amazonian Craton, Brazil: Implications for architecture and zoning of A-type granites: Journal of South American Earth Sciences, 25, 100-115.
Forster, H., 1978, Mesozoic-Cenozoic metallogenesis in Iran: Journal of the Geological Society of London, 135, 443–455.
Guan, Z. N., 2005, Geomagnetic Field and Magnetic Exploration: Geological Publishing House, Beijing.
Hinze, W. J., Von Frese, R. R. B., and Saad, A. H., 2013, Gravity and Magnetic Exploration: Principles, Practices and Applications: Cambridge University Press, New York.Miller, H. G., and Singh, V., 1994, Potential field tilt -A new concept for location of potential field sources: Journal of Applied Geophysics, 32, 213-217.
Mohamed, A., Abdelrady, M., Alshehri, F., Mohammed, M. A., and Abdelrady, A., 2022, Detection of mineralization zones using aeromagnetic data: Applied Sciences, 12, 9078.
Ranjbar, H., Hassanzadeh, H., Torabi, M., and Ilaghi, O., 2001, Integration and analysis of airborne geophysical data of the Darrehzar area, Kerman Province, Iran, using principal component analysis: Journal of Applied Geophysics, 48(1), 33-41, ISSN 0926-9851.
Riahi, S., Abedi, M., and Bahroudi, A., 2021, Integration of airborne geophysics and satellite imagery data for exploration targeting in porphyry Cu systems: Chahargonbad district, Iran: Geophysical Prospecting Journal, 99(5), 1116-1137.Riahi, S., Bahroudi, A., Abedi, M., and Aslani, S., 2022, Hybrid outranking of geospatial data: Multi attributive ideal-real comparative analysis and combined compromise solution: Geochemistry, 82(3), 125898.
Roy, B., and Clowes, R. M., 2000, Seismic and potential-field imaging of the Guichon Creek batholith, British Columbia, Canada, to delineate structures hosting porphyry copper deposits: Geophysics, 65, 1418-1434.
Sillitoe, R. H., 2010, Porphyry copper systems: Economic Geology, 105, 3-41.
Woods, K. T., and Webster, S. S., 1985, Geophysical signature of gold and porphyry copper mineral deposits in the Lachlan Fold Belt, NSW: 4th ASEG Coference, 325-331.
Xiao, F., and Wang, Z., 2017, Geological interpretation of Bouguer gravity and aeromagnetic data from the Gobi-desert covered area, Eastern Tianshan, China: Implications for porphyry Cu-Mo polymetallic deposits exploration: Ore Geology Reviews, 80, 1042-1055, ISSN 0169-1368.
Yousefi, M., and Carranza, E. J. M., 2015, Fuzzification of continuous-value spatial evidence for mineral prospectivity mapping: Computers & Geosciences, 74, 97–109.
Zarasvandi, A., Liaght, S., and Zentilli, M., 2005, Porphyry copper deposits of the Urumieh-Dokhtar magmatic arc, Iran, super porphyry copper and gold deposits, A global perspective: PGC publishing Adelaide, 2, 441-452.