Whole Rock Geochemical Techniques for Discrimination of Hydrothermal Alteration of the Kuh-e Dom Fe−Cu (±Au) prospect, Central Iran

Authors

Faculty of Earth Sciences, Kharazmi University, Tehran, Iran

Abstract

The intrusive rocks hosting Fe−Cu (±Au) mineralization at Kuh-e Dom prospect affected by mass transfer associated with sodic, potassic and quartz-calcite (±chlorite-sulfide) alteration caused quartz-hematite-gold vein-breccia mineralization. Resultant hydrothermal alteration zonation shows that increasing Na-rich mineral assemblages with proximity to mineralization veins, K-rich mineral assemblages distal from veins and quartz-calcite (±chlorite-sulfide) occurs as disseminated in the veins and mineralization host rock. In this contribution, we describe the whole rock geochemical techniques of the altered and fresh-rock equivalents for mass transfer evaluating, compositional gradients, and molar ratios for the discrimination of the hydrothermal alteration. Sodic (-calcic) alteration occurred at stage I accompanied with albite and mass gains are apparent in Na2O, CaO, Fe2O3, Cu and Co whereas mass losses in K2O, MgO and Rb occur to the proximal veins and ore-bearing zones. Potassic alteration accompanied with orthose, quartz and calcite occurred at stage II and displays mass gains in K2O, Ba, Y and Sr whereas Na2O, CaO, MgO and Fe2O3 are depleted far from the veins. Quartz-calcite (±chlorite-sulfide) alteration occurs as disseminated in the veins and accompanied with relative enrichment of Fe2O3, MgO, CaO, and LREE (i.e., Ce, La and Nd) associated with depletion of Na2O, K2O, Ba, and Sr. In the base of molar ratios in the alteration assemblages, the (2Ca+Na+K)/Al highest ratio belongs to mafic and felsic dikes with 1.4 and 1.2, accordingly. The negative correlation between Fe and Cu mineralization vs. K/(2Ca+Na+K) molar ratio shows enrichments of this elements in the veins and ore-bearing zones and geochemical relations with sodic (-calcic) alteration in the area. At the base of petrographic, whole rock geochemistry and molar ratio evidences of the Kuh-e Dom alteration rocks, the high proportion of sodic (-calcic) alteration in the area occurs with mafic and felsic rocks which cause hydrothermal fluid mobilization and Fe−Cu (±Au) vein-breccia mineralization. The studies of this metal enrichment associated with geochemistry of alteration in the dikes of the south area can be a criterion for progress of prospecting process and exploration development at mineralization area.
 

Keywords

References

افشونی. ز.، اسماعیلی. د.، اسدی هارونی. ه.، 1392، مطالعه ایزوتوپ‌های پایدار (O، H و S) در زون‌های دگرسانی فیلیک و پتاسیک-فیلیک کانسار مس-مولیبدن پورفیری کهنگ (شمال شرق اصفهان)، مجله زمین‌شناسی کاربردی پیشرفته، شماره 7، ص 64-73.
خلعتبری. ر.، 1371، پلوتونیسم ترشیری منطقه اردستان و ایران مرکزی، پایان‌نامه کارشناسی ارشد، سازمان زمین شناسی کشور.
ربیعی. م.، 1385، اکتشافات ژئوشیمیایی ناحیه کوه‌دم و بررسی ژنز اندیس طلای آن، پایان‌نامه کارشناسی ارشد، دانشگاه خوارزمی تهران، 130صفحه.
سامانی. ب.، 1373، فلززایی و ایالت‌های متالوژنی ایران، سیزدهمین گردهمایی علوم‌زمین سازمان زمین‌شناسی کشور.
سرجوقیان. ف.، 1391، ماهیت پلوتونیسم (شمال‌شرق اردستان): پدیده‌های زمین‌شناسی و تحولات ماگمایی آن، رساله دکتری دانشگاه تهران.
شرکت تهیه و تولید مواد معدنی ایران.، 1388، مطالعات اکتشافات تفصیلی آنومالی‌های طلا و مس منطقه کوه‌دم.
نبوی. م.ح.، هوشمندزاده. ع.و.، حمدی. ب.، 1363، نکته‌ها و پیچیدگی‌هایی از زمین‌شناسی دگرگونه سنگ‌های منطقه انارک-خور جندق (ایران مرکزی) در پیوند با کارهای زمین‌شناسی، شرکت تکنواکسپورت (ژئومتال).
نجفیان. ط.، فتحیان‌پور. ن.، رنجبر. ح.، بخش‌پور. ر.، 1391، شناسایی پدیده‌های طیفی ناشناخته از داده‌های تلفیقی تصاویر ماهواره‌ای ALI+ASTER و ابر طیفی Hyperion برمینای روش ضریب همبستگی، مطالعه موردی (محدوده معدنی مس‌سرچشمه)، مجله زمین‌شناسی کاربردی پیشرفته، شماره 5، ص 59-67.
73
 
Appleyard. E.C., 1991, SOMA-A package of Fortran programs for calculating mass exchange in metasomatic and altered rocks, Waterloo, ON, University of Waterloo, 65 p.
Babcock. R.S., 1973, Computational models of metasomatic processes, Lithos, Vol: 6, p: 279–290
Bagheri. S., Stampfli. G.M., 2008, The Anarak, Jandaq and Posht-e-Badam metamorphic complexes in central Iran: New geological data, relationships and tectonic implications, Tectonophysics, No. 451, p: 123–155
Barton. M.D., Johnson. D.A., 2000, Alternative brine sources for Fe–oxide (–Cu–Au) systems: implications for hydrothermal alteration and metals. In: Porter TM (ed) Hydrothermal iron oxide copper gold & related deposits: a global perspective, Australian Mineral Foundation, Adelaide, p: 43–60
Giggenbach. W.F., 1981, Geothermal mineral equilibria, Geochimica et Cosmochimica Acta, Vol. 45, p: 393–410
Giggenbach. W.F., 1984, Mass transfer in hydrothermal alteration systems—a conceptual approach, Geochimica et Cosmochimica Acta, Vol. 48, p: 2693–2711
Giggenbach. W.F., 1997, The origin and evolution of fluids in magmatic-hydrothermal systems, in Barnes, H.L., ed., Geochemistry of hydrothermal ore deposits, 3rd ed.: New York, John Wiley and Sons, p: 737–796
Grant. J.A., 1986, The isocon diagram—a simple solution to Gresens’ equation for metasomatic alteration, Economic Geology, Vol. 81, p: 1976–1982
Gresens. R.L., 1967, Composition-volume relationships of metasomatism, Chemical Geology, Vol. 2, p: 47–65
GSI (Geological Survey of Iran). 1981, Geological map of Iran 1:100,000 series, Sheet 6557, Kuh-e Dom
GSI (Geological Survey of Iran). 1979, Geological map of Iran 1:250,000 series, No.G7, Anarak
Hitzman. M.W., Oreskes. N., Einaudi. M.T., 1992, Geological characteristics and tectonic setting of Proterozoic iron oxide (Cu–U–Au–REE) deposits, Precambrian Res, Vol: 58, p: 241–287
Leitch. C.H.B., Lentz. D.R., 1994, The Gresens approach to mass balance constraints of alteration systems, Geological Association of Canada Short Course Notes, Vol: 11, p: 161–192
MacLean. W.H., 1990, Mass change calculations in altered rock series, Mineralium Deposita, Vol: 25, p: 44–49
MacLean. W.H., Barrett. T.J., 1993, Lithogeochemical techniques using immobile elements, Journal of Geochemical Exploration, Vol: 48, p: 109–133
MacLean. W.H., Kranidiotis. P., 1987, Immobile elements as monitors of mass transfer in hydrothermal alteration: Phelps Dodge massive sulfide deposit, Matagami, Quebec, Economic Geology, Vol: 82, p: 951–962
McDonough. W.F., Sun. S.S., 1995, The composition of the earth, Chemical Geology, Vol: 120, p: 223–253
Oliver. N.H.S., Cleverley. J.S., Mark. G., Pollard. P.J., Fu. B., Marshall. L.J., Rubenach. M.J., Williams. P.J., Baker. T., 2004, Modeling the role of sodic alteration in the genesis of iron–oxide–copper–gold deposits, eastern Mount Isa block, Australia, Economic Geology, Vol: 99, p: 1145–1176
Pollard. P.J., 2001, Sodic (–calcic) alteration in Fe–oxide–Cu–Au districts: an origin via unmixing of magmatic H2O–CO2–NaCl±CaCl2–KCl fluids, Miner Deposita, Vol: 36, p: 93–100
Stanley. C.R., Madeisky. H.E., 1994, Lithogeochemical exploration for hydrothermal ore deposits using Pearce element ratio analysis, Geological Association of Canada Short Course Notes, Vol: 11, p: 193–212
Technoexport., 1981, Detail geology prospecting in the Anarak Area Central Iran, Geological Survey of Iran, Report No. 9
Warren. I., Simmons. S.F., Mauk. J., 2007, Whole-Rock Geochemical Techniques for Evaluating Hydrothermal Alteration, Mass Changes, and Compositional Gradients Associated with Epithermal Au-Ag Mineralization, Economic Geology, Vol: 102, p: 923–948
Zanchi. A., Zanchetta. S., Garzanti. E., Balini. M., Berra. F., Mattei. M., Muttoni. G., 2009, The Cimmerian evolution of the Nakhlak–Anarak area, Central Iran, and its bearing for the reconstruction of the history of the Eurasian margin in Brunet, M.F., Wilmsen, M. and Granath, J. W. (eds) South Caspian to Central Iran Basins, The Geological Society, London, Special Publications, Vol: 312, p: 261–286

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