عنوان مقاله [English]
نویسندگان [English]چکیده [English]
The Sadrabad iron deposit is located 28 km west of Sadrabad village (west of Yazd) at the Urumieh-Dokhtar magmatic arc. The Upper Triassic-lower Jurassic sedimentary rocks (dolomitic limestone, sandstone, shale and marl), the Cenozoic granite to dioritic intrusive bodies and the Quaternary unconsolidated deposits outcrop in the study area. The intrusive bodies are of I-type calc-alkaline series formed in syn-collision to post collision settings of continental margin subduction zone. The later quartz monzodiorite intrusions played a significant role in iron mineralization. The location of mineralization controlled by NW-SE and NE-SW fault systems. Olivine, clinopyroxene, garnet, tremolite-actinolite, epidote, serpentine, talc, phlogopite, calcite, dolomite, brucite and hydromagnesite are the main skarn minerals. The ore bodies consist mainly of magnetite with minor pyrite, chalcopyrite and pyrhotite which occur as massive, vein-veinlets, brecciate and disseminated magnetite. Skarn formation occurs in two prograde and retrograde stages. Olivine, clinopyroxene and garnet formed in prograde and the remaining minerals in retrograde stages. The temperature and salinity of fluid inclusions in quartz veins associated with serpentine (in retrograde stage) range from 217 to 280˚c and 8 to 16 (wt %) NaCl respectively, indicating the mixing of magmatic and meteoric water in retrograde stage. The Mg-bearing silicates such as serpentine, phlogopite, diopside and talc in the Sadrabad skarn, point to the mineralization of magnesian type.
Agard, P., Omrani, J., Jolivet, F. and Mouthereau, P. (2005) Convergence history across Zagros (Iran): constraints from collisional and earlier deformation. International Journal of Earth Sciences 94: 401 – 419.
Baharifar, A. A. (2011) Mineralogy and origin of garnet in acidic volcanic rocks of Dastgerd area, Qom. Petrology 4: 1-14 (in Persian).
Baniadam, F. (2013) Report on geological map (1:5000) of Sadrabad iron deposit. Madankaran Khak-e-Sorkh-e- Nodoshan Co., Tehran (in Persian).
Barnes, H. L. (1979) Geochemistry of hydrothermal ore deposits. 2nd edition, Wiley, New York.
Chappell, B. W. and White, A. J. R. (1992) I and S type granites in the Lachlan fold belt. Earth Science 83: 1- 26.
Cox, K.G., Bell, J. D. and Pankhurst, R.J. (1979) The interpretation of igneous rocks. George Allen and Unwin, London.
Droop, G. T. R. (1987) A general equation for estimating Fe3+ concentrations in ferromagnesian silicates and oxides from microprobe analyses, using stoichiometric data. Mineralogical Magazine 51: 431-435.
Einaudi, M. T. and Burt, D. M. (1982) Introduction, terminology, classification and composition of skarn deposits. Economic Geology 77: 745–754.
Ghanei, J. and Mackizadeh, M. A. (2011) Textural assemblage relationships between clintonite-spinel-garnet in the central Iranian skarns as evidence of clintonite genesis. Petrology 4: 65-72 (in Persian).
Irvine, T. N. and Baragar, W. R. A. (1971) A guide to the chemical classification of the common volcanic rocks. Canadian Journal of Earth Sciences 8: 523–548.
Kamvong, T. and Zaw, K. (2009) The origin and evolution of skarn–forming fluids form the Phu Lon deposit, northern Loei Fold Belt, Thailand: Evidence form fluid inclusion and sulfur isotope studies. Journal of Asian Earth Sciences 34: 624–633.
Karimi, M. (2012) Mineralogy and geochemistry of Sork iron deposit, Yazd. Proceeding of the 1st National congress of Iranian geologists, Azad University, Shiraz, Iran (in Persian).
Kesler, S. E. (2005) Ore-forming fluids. Ore Geology Reviews 12: 18–113.
Kohsari, A. (2007) The mineralogy of Koh-e-Ahan skarn, Yazd. Proceeding of the 15th Congress of Crystallography and Mineralography Society of Iran, Mashhad University, Mashhad, Iran (in Persian).
Kusku. I., Kascu. G., Meinert. L. and Floyed. P. (2002) Tectonic setting and petrogenesis of the Celebi granitoid (Turkey) and comparison with world skarn granitoids. Geochemical Exploration 76: 175–194.
Liaghat, S. (2011) Characteristics of intrusive bodies at SW Yazd and comparison with world skarn granitoids. Journal of Science 14: 53-63 (in Persian).
Meinert, L. D, Dipple, G. N., and Nicolescu, S. (2005) World Skarn Deposits. Economic Geology 100th anniversary volume 299-336.
Meinert. L. D. (1995) Mineralogy and petrology of iron skarns in Western British Colombia, Canada. Economic Geology 79: 869–882.
Moshtagh, S. (2014) Mineralogy, Alteration, Petrogenesis and ore forming process of Sadrabad iron deposit, South West of Yazd. M. Sc. thesis, University of Isfahan, Isfahan, Iran (in Persian).
Pearce, J. A., Haris, N. B. W. and Tindle, A. G. (1994) Trace element discrimination diagrams for the tectonic interpretation of granitic rocks. Journal of Petrology 25: 956–983.
Pirajno, F. (2009) Hydrothermal processes and mineral systems. Springer, New York, USA.
Rickwood, P. C., (1968) On recasting analyses of garnet into end-member molecules. Contributions to Mineralogy and Petrology 18: 175-198.
Robb, L. (2005) Introduction to ore-forming processes. Black well Publishing, Oxford.
Roedder. E. and Bodnar. R. J. (1980) Geological pressure determination from fluid inclusion studies. Annual Review of Earth and Planetary Science 8: 263–301.
Taghipour, B. (2011) Petrogenesis of porphyry related skarn in Aliabad-Darreh Zereshk, Yazd. Journal of Economic Geology 1: 79-92.
Wilkinson. J. J. (2001) Fluid inclusion in hydrothermal mineral deposits. Lithos 55: 229_272.
Zahedi, A. and Boomeri, M. (2014) Studies on fluid inclusions and stable isotopes (C, O and S) during generation and evolution of Khut copper skarn West of Yazd, Central Iran. Petrology 20: 107-127 (in Persian).