Estimation of geothermal parameters using spectral analysis and 3D inverse modelling of the magnetic data in the Mahallat geothermal field

Authors

1 Mining Exploration Engineering Department, Faculty of Mining, Petroleum & Geophysics Engineering, Shahrood University of Technology, Shahrood, Iran

2 Geophysics Department, Faculty of Mining, Petroleum & Geophysics Engineering , Shahrood University of Technology, Shahrood, Iran

3 Research Institute of Applied Sciences, Shahid Beheshti University, Daneshjoo Blvd, Tehran, Iran

Abstract

The existence of hot springs, extensive travertine deposits, hydrothermal alteration ranges, and the presence of faults in the Mahallat indicate an important geothermal system. In order to recognize the reservoir of the geothermal system as well as areas with magnetic anomalies, in the study area were conducate the magnetometry measurements In the length of 10 profiles,with total length 160 km and with an station spacing of 40 meters. The main purpose of this study is to estimate the bottom (Curie point depth) and top depth of magnetic sources also thermal gradient and heat flow using spectral analysis (centroid method). As well as conducted 3D inverse modeling of the magnetic data by Li-Oldenberg algorithm, in order to determine of geometries of the heat source. Conformity between of the obtained results by inverse modelling and centroid method indicate the existence of geothermal reservoir in the north part of study area. The results indicated that the range of variations in the bottom- depth, top depth of magnetic sources, varies from 1350 to 3400 meter,1230 to 2390meter, respectively.

Keywords


Aydın, İ., Karat, H.İ., Koçak, A., 2005. Curie-point depth map of Turkey. Geophysical Journal International 162(2), 633-640.
Babaei, B., Falahipour, M., Baghzendani, H. R., 2016. Recognition of geothermal reservoirs using inverse modeling of gravimetric data in the Mahallat hot springs. Journal of Research on Applied Geophysics 3, 43-49.
Bansal, A.R., Gabriel, G., Dimri, V.P., Krawczyk, C.M., 2011. Estimation of depth to the bottom of magnetic sources by a modified centroid method for fractal distribution of sources: An application to aeromagnetic data in Germany. Geophysics 76(3), 11-22.
Beitollahi, A., 1996. Travertine formation and the origin of the high natural radioactivity in the region of Mahallat hot springs (Doctoral dissertation, M. Sc. Thesis. Islamic Azad University of Tehran, Iran) (In Persian).
Bhattacharyya, B.K., Leu, L.K., 1975. Analysis of magnetic anomalies over Yellowstone National Park: mapping of Curie point isothermal surface for geothermal reconnaissance. Journal of Geophysical Research 80(32), 4461-4465.
Blakely, R.J., 1988. Curie temperature isotherm analysis and tectonic implications of aeromagnetic data from Nevada. Journal of Geophysical Research: Solid Earth 93(10), 11817-11832.
Blakely, R.J., 1996. Potential theory in gravity and magnetic applications. Cambridge University Press.
Bouligand, C., Glen, J.M., Blakely, R.J., 2009. Mapping Curie temperature depth in the western United States with a fractal model for crustal magnetization. Journal of Geophysical Research: Solid Earth 114 (11).
Connard, G., Couch, R., Gemperle, M., 1983. Analysis of aeromagnetic measurements from the Cascade Range in central Oregon. Geophysics 48(3), 376-390.
Dolmaz, M.N., Ustaömer, T., Hisarli, Z.M., Orbay, N., 2005. Curie point depth variations to infer thermal structure of the crust at the African-Eurasian convergence zone, SW Turkey. Earth, planets and space 57(5), 373-383.
Hisarli, Z.M., Dolmaz, M.N., Okyar, M., Etiz, A., Orbay, N., 2012. Investigation into regional thermal structure of the Thrace Region, NW Turkey, from aeromagnetic and borehole data. Studia Geophysica et Geodaetica56(1), 269-291.
Hsieh, H.H., Chen, C.H., Lin, P.Y., Yen, H.Y., 2014. Curie point depth from spectral analysis of magnetic data in Taiwan. Journal of Asian Earth Sciences 90, 26-33.
Karastathis, V.K., Papoulia, J., Di Fiore, B., Makris, J., Tsambas, A., Stampolidis, A., Papadopoulos, G.A., 2010. June. Exploration of the deep structure of the central Greece geothermal field by passive seismic and Curie depth analysis. In 72nd EAGE Conference and Exhibition incorporating SPE Europe 2010.
Li, Y., Oldenburg, D.W., 1996. 3-D inversion of magnetic data. Geophysics 61(2), 394-408.
Mirzaei, M., Moghaddam, M.M., Oskooi, B., Ghadimi, F., Jazayeri, S., 2013. Processing and interpretation of ground magnetic data corresponding to geothermal resources using Euler and AN-EUL method, north-east of Mahallat. Journal of Earth Space Physics 39, 83–96.
Mohammadzadeh-Moghaddam, M., Oskooi, B., Mirzaei, M., Jouneghani, S. J., 2012.  September. Magnetic studies for geothermal exploration in Mahallat, Iran. In Istanbul 2012-International Geophysical Conference and Oil & Gas Exhibition, Society of Exploration Geophysicists and The Chamber of Geophysical Engineers of Turkey, 1-4.
Nouraliee, J., Ebrahimi, D., 2012. Geochemical Studies in Mahallt Geothermal Region, Internal Report. Niroo Research Institute (NRI), Tehran, Iran.
Nouraliee, J., Porkhial, S., Mohammadzadeh-Moghaddam, M., Mirzaei, S., Ebrahimi, D. and Rahmani, M.R., 2015. Investigation of density contrasts and geologic structures of hot springs in the Markazi Province of Iran using the gravity method. Russian Geology and Geophysics 56(12), 1791-1800.
Nouraliee, J., Shahhosseini, A., 2012.Geological map of Mahallat geothermal region, Scale: 1:25,000. Niroo Research Institute (NRI), Tehran, Iran (In Persian) .
Nwankwo, L.I., Shehu, A.T., 2015. Evaluation of Curie-point depths, geothermal gradients and near-surface heat flow from high-resolution aeromagnetic (HRAM) data of the entire Sokoto Basin, Nigeria. Journal of Volcanology and Geothermal Research 305, 45-55.
Okubo, Y., Matsushima, J., Correia, A., 2003. Magnetic spectral analysis in Portugal and its adjacent seas. Physics and Chemistry of the Earth, Parts A/B/C 28 (9-11), 511-519.
Oskooi, B., Darijani, M., 2014. 2D inversion of the magnetotelluric data from Mahallat geothermal field in Iran using finite element approach. Arabian Journal of Geosciences 7(7), 2749-2759.
Phillips, N.D., 2002. Geophysical inversion in an integrated exploration program: Examples from the San Nicolas deposit (Doctoral dissertation, University of British Columbia).
Rezaie, M., Ghorbani, M., Bomeri, M., 2009. The hydrogeology and geothermology of the Mahallat hot springs. in: 1st National Conference on Hydrogeology. Behbehan, Iran.
Saada, S.A., 2016. Curie point depth and heat flow from spectral analysis of aeromagnetic data over the northern part of Western Desert, Egypt. Journal of Applied Geophysics 134, 100-111.
Soligo, M., Tuccimei, P., Barberi, R., Delitala, M.C., Miccadei, E., Taddeucci, A., 2002. U/Th dating of freshwater travertine from Middle Velino Valley (Central Italy): paleoclimatic and geological implications. Palaeogeography, Palaeoclimatology, Palaeoecology 184(1-2), 147-161.
Stampolidis, A., Kane, I., Tsokas, G.N., Tsourlos, P., 2005. Curie point depths of Albania inferred from ground total field magnetic data. Surveys in Geophysics 26(4), 461-480.
Tanaka, A., Okubo, Y., Matsubayashi, O., 1999. Curie point depth based on spectrum analysis of the magnetic anomaly data in East and Southeast Asia. Tectonophysics 306(3-4), 461-470.
Tselentis, G.A., 1991. An attempt to define Curie point depths in Greece from aeromagnetic and heat flow data. Pure and Applied Geophysics 136(1), 87-101.
Xu, Y., Hao, T., Zeyen, H., Nan, F., 2017. Curie Point Depths in North China Craton Based on Spectral Analysis of Magnetic Anomalies. Pure and Applied Geophysics 174(1), 339-347.