Magmatic-hydrothermal fluid evolution of the Dalli porphyry Cu-Au deposit; using Amphibole and Plagioclas mineral chemistry

Document Type : Research Article

Authors

• Houshang Pourkaseb ¹
• Alireza Zarasvandi ¹
• Madineh Saed ¹
• Ali Reza Davoudian Dehkordy ²

¹ Shahid Chamran University of Ahvaz

² Shahrekord

10.22067/econg.v9i1.51704

Abstract

Introduction
The formation of porphyry copper deposits is attributed to the shallow emplacement, and subsequent cooling of the hydrothermal system of porphyritic intrusive rocks (Titley and Bean, 1981). These deposits have usually been developed along the chain of subduction-related volcanic and calc-alkalin batholiths (Sillitoe, 2010). Nevertheless, it is now confirmed that porphyry copper systems can also form in collisional and post collisional settings (Zarasvandi et al., 2015b). Detailed studies on the geochemical features of ore-hosting porphyry Cu-Mo-Au intrusions indicate that they are generally adakitic, water and sulfur- riched, and oxidized (Wang et al., 2014). For example, high oxygen fugacity of magma has decisive role in transmission of copper and gold to the porphyry systems as revealed in (Wang et al., 2014). In this regard, the present work deals with the mineral chemistry of amphibole and plagioclase in the Dalli porphyry Cu-Au deposit. The data is used to achieve the physical and chemical conditions of magma and its impact on mineralization. Moreover, the results of previous studies on the hydrothermal system of the Dalli deposit such as Raman laser spectroscopy and fluid inclusion studies are included for determination of the evolution from magmatic to hydrothermal conditions.

Materials and methods
In order to correctly characterize the physical and chemical conditions affecting the trend of mineralization, 20 least altered and fractured samples of diorite and quartz-diorite intrusions were chosen from boreholes. Subsequently, 20 thin-polished sections were prepared in the Shahid Chamran University of Ahvaz. Finally, mineral chemistry of amphibole and plagioclase were determined using electron micro probe analyses (EMPA) in the central lab of the Leoben University.

Results
Amphibole that is one of the the main rock-forming minerals can form in a wide variety of igneous and metamorphic rocks. Accordingly, amphibole chemistry can be used as an indicator for characterizing the conditions involved during the evaluation of magma crystallization i.e., pressure, temperature, liquid water content and oxygen fugacity. Most recent studies on the porphyry copper intrusions in the Urumieh- Dokhtar magmatic arc by (Zarasvandi et al., 2015a), indicate that all of the mineralized porphyry systems (Dalli porphyry is included) consistently show high levels of La/Sm and Sm/Yb, with concave upward patterns in the rare earth elements’ spider diagrams. Importantly, such features indicate high crustal assimilation in a relatively thickened crust and provide insight into the contribution of hornblende during the development of mineralized porphyry systems in the Urumieh- Dokhtar belt. The results of this study indicate that amphiboles of Dalli intrusions belong to the calsic group and range in composition from magnesio- hornblende, to edenite, magnesiohastingsite, and tschermakite. (Ridolfi et al., 2010), indicating that the alumina content of amphibole could be used for geobarometry. The calculations of geobarometry for quartz diorite intrusions of Dalli indicate that they formed in the pressure range of 136 to 287 (MPa). Also, calculation of magmatic water content using amphibole geochemistry indicates that the water content of quartz diorite intrusions in the Dalli were between 4.6- 5.7 (wt. %). The results of plagioclase chemistry indicate that there is a little zoning in this mineral. Also, the plagioclase composition varies from Or0.01 to Ab 0.48, An 0.50, Or 0.018, Ab 0.62 and An 0.35. They mostly have Andesine and Labradorite compositions.

Discussion
Amphibole minerals of the Dalli intrusions are calcic type and exhibit geochemical signatures of subduction zones. Also, characterizing the source of ore-hosting intrusions with amphibole chemistry indicate that parental magma of Dalli intrusion were generated from mixing of mantle melts with crustal materials. It seems that in an ongoing process of closure of Neo-Tethys, during compression and crustal shortening favourable conditions were provided for mixing of mantle melts with crustal materials. The geothermobaromerty calculations using amphibole and plagioclase minerals indicate conditions of 777 - 850 oC and 1-4 Kbar, representing magmatic stage of Dalli intrusions. Also, amphibole minerals are characterized by Fetot/Fetot + Mg > 0.3 and AlIV > 0.7 which reveal the presence of primary oxidative magma in the Dalli porphyry Cu-Au deposit. Oxidative conditions seem to have prevailed during the onset of the hydrothermal stage of the Dalli porphyry deposit. This is because it has been confirmed by laser Raman spectroscopy analyses that the most primitive quartz veins in the potassic alteration of the Dalli deposit are characterized by the presence of anhydrite and hematite minerals (see Zarasvandi et al., 2015b). Also, microthermometry results on the most primitive barren quartz veins in potassic alteration represent temperatures as high as 620oC which indicate the beginning temperature of hydrothermal conditions.

Acknowledgements
Many thanks are due to the office of vice-chancellor of the Shahid Chamran University of Ahvaz for valuable information concerning the field work and sampling.

References
Ridolfi, F., Renzulli, A. and Puerini, M., 2010. Stability and chemical equilibrium of amphibole in calc-alkaline magmas: An overview, new thermobarometric formulations and application to subduction-related volcanoes. Contributions to Mineralogy and Petrology, 160(1): 45–66.
Sillitoe, R.H., 2010. Porphyry Copper Systems. Economic Geology, 105(1): 3-41.
Titley, S.R. and Beane, R.E., 1981. Porphyry copper deposits. Part 1. Geologic Setting, Petrology, and Tectogenesis. In: J.W. Hedenquist, J.F.H. Thompson, R.J. Goldfarb and J.P. Richards (Editors), Economic Geologists, 75th Anniversary Volume. Society of Economic Geologists, U.S.A, pp. 214-234.
Wang, R., Richards, J.P., Hou, Z.Q., Yang, Z.M., Gou, Z.B. and DuFrane, A., 2014. Increasing Magmatic Oxidation State from Paleocene to Miocene in the Eastern Gangdese Belt, Tibet: Implication for Collision-Related Porphyry Cu-Mo ±Au Mineralization. Economic Geology, 109(7): 1943–1965.
Zarasvandi, A., Rezaei, M., Sadeghi, M., Lentz, D., Adelpour, M. and Pourkaseb, H., 2015a. Rare earth element signatures of economic and sub-economic porphyry copper systems in Urumieh–Dokhtar Magmatic Arc (UDMA), Iran. Ore Geology Reviews, 70: 407-423.
Zarasvandi, A., Rezaei, M., Raith, J., Lentz, D., Azimzadeh, A.M. and Pourkaseb, H., 2015b. Geochemistry and fluid characteristics of the Dalli porphyry Cu–Au deposit, Central Iran. Journal of Asian Earth Sciences, 111: 175-191.

Keywords

• Plagioclas
• Amphibole
• Oxygen fugacity
• EMPA
• Dalli
• Urumieh- Dokhtar Magmatic Arc

20.1001.1.20087306.1396.9.1.4.0

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References

Alai, Mahabadi, S., Kohansal, R., Ghomian, Y. and Soltani, M.V., 2000. Geological map of SALAFCHEGAN- KHORHE, scale 1:100,000. Geological Survey of Iran.

Almeev, R.R. and Ariskin, A.A., 1996. Mineral-melt equilibria in a hydrous basaltic system: computer modeling. Geochemistry International, 34(7): 563-573.

Anderson, J.L. and Smith, D.R., 1995. The effects of temperature and fO2 on the Al- in hornblende barometer. American Mineralogist, 80(5-6): 549–559.

Asadi, F., 2015. The Investigation characteristics of Physico-Chemical of the fluid inclusions at the Dalli Cu-Au porphyry deposit, Delijan, Markazi province. M.Sc. Thesis, Shahid Chamran University, Ahvaz, Iran, 118 pp. (in Persian with English abstract)

Asadi Harouni, H., 2010. Final exploration report at Dalli Cu–Au deposit. Unpublished report (Industry, Mine and Trade of Central Province), Central Province, Report DP-01, 40 pp.

Ayati, F., Noghreyan, M.K. and Khalili, M., 2012. Petrographic and mineral-chemistry of the magmatic-alteration zones South of Salafchegan. Petrology, 2)8(: 1-20. (in Persian with English abstract)

Ayati, F., Yavuz, F., Asadi Harouni, H., Richards, J.P. and Jourdan, F., 2013. Petrology and geochemistry of calc-alkaline volcanic and subvolcanic rocks, Dalli porphyry copper–gold deposit, Markazi Province, Iran. International Geology Review, 55(2): 158-184.

Blundy, J.D. and Holland, T.J.B., 1990. Calcic amphibole equilibria and a new amphibole plagioclase geothermometer. Contributions to Mineralogy and Petrology, 104(2): 208-224.

Camus, F., 2005. The Andean porphyry systems. In: T.M. Porter (Editor), Super Porphyry Copper & Gold Deposits - A Global Perspective. PGC Publishing, Adelaide, pp. 45-63.

Chivas, A.R., 1981. Geochemical evidence for magmatic fluids in porphyry copper mineralization. Contributions to Mineralogy and Petrology, 78(4):389-403.

Cloos. M., 2001. Bubbling Magma Chambers, Cupolas and Porphyry Copper Deposits. International Geology Reviwe, 43(4): 285-311.

Coltorti, M., Bondaiman, C., Faccini, B., Gregoire, M., O’Reilly, S.Y. and Powell, W., 2007. Amphiboles from suprasubduction and intraplate lithospheric mantle. Lithos, 99(1-2): 68-84.

Dachs E., 2004. PET: Petrological elementary tools for Mathematica an update. Computers and Geoscience, 30(2):173-182.

Daneshjou, M., 2014. Geology, Geochemistry and Gensis model of the Dalli Cu-Au Porphyry Deposit, Delijan, Markazi province. M.Sc. Thesis, Shahid Chamran University, Ahvaz, Iran, 141 pp. (in Persian with English abstract)

Davidson, J., Turner, S., Handley, H., Macpherson, C. and Dosseto, A., 2007. Amphibole "sponge" in arc crust? Geology, 35(9): 787–790.

Deer, W.A., Howie, R.A. and Zussman, J., 1991. An introduction to rock forming mineral. Longman, London, 787 pp.

Eugster, H.P. and Wones, D.R., 1963. Stability Relations of the Ferruginous Biotite, Annite. Journal of Petrology, 3(1): 82–125.

Ewart, A., 1979. A review of the mineralogy and chemistry of tertiary recent dacitic, latitic, rhyolitic and related salic volcanic rocks. In: B. Fred (Editor), Trondhjemites, dacites, and related rocks. Springer- Verlag, Berlin, pp. 12–101.

Frost, B.R., 1991. Introduction to oxygen fugacity and its petrologic importance. Reviews in Mineralogy and Geochemistry, 25: 1–9.

Giret, A., Bonin, B. and Leger, J.M., 1980. Amphibole compositional trends in oversaturated and undersaturated alkaline plutonic ring-complexes. Canadian Mineralogist, 18(4): 481–495.

Hammarstrom, J.M. and Zen, E., 1986. Aluminum-in-hornblende: an empirical igneous geobarometer. American Mineralogist, 71(11-12): 1297-1313.

Helmy, H.M., Ahmed, A.F., El Mahallawi, M.M. and Ali, S.M., 2004. Pressure, temperature and oxygen fugacity conditions of calc-alkaline granitoids, Eastern Desert of Egypt, and tectonic Implication. Journal of African Earth Science, 38(3): 255-268.

Hendry, D.A.F., Chivas, A.R., Long, J.V.p. and Reed, S.J.B., 1985. Chemical differences between minerals from mineralizing and barren intrusions from some North American prophyry copper deposits. Contributions to Mineralogy and Petrology, 89(4): 317-329.

Hezarkhani, A., 2006. Hydrothermal evolution of the Sar-Cheshmeh porphyry Cu–Mo deposit, Iran: Evidence from fluid inclusions. Journal of Asian Earth Sciences, 28(4-6): 409–422.

Hirschmann, M.M., Ghiorso, M.S., Davis, F.A., Gordon, S.M., Mukherjee, S., Grove, T.L., Krawczynski, M., Medard, E. and Till, C.B., 2008. Library of Experimental Phase Relations (LEPR): A database and Web portal for experimental magmatic phase equilibria data. Geochemistry, Geophysics, Geosystems, 9(3): 1–15.

Holland, T.J.B. and Blundy, J.D., 1994. Non-ideal interactions in calcic amphiboles and their bearing on amphibole- plagioclase thermometry. Contributions to Mineralogy and Petrology, 116: 433-447.

Hollister, L.S., Grissom, G.C., Peters, E.K., Stowell, H.H. and Sisson, V.B., 1987. Confirmation of the empirical correlation of Al in hornblende with pressure of solidification of calc-alkaline plutons. American Mineralogist, 72(3-4): 231-239.

Jiang, C.Y. and An, S.Y., 1984. On chemical characteristics of calcic amphiboles from igneous rocks and their petrogenesis significance. Journal of Mineralogy and Petrology, 03: 1–9. (in Chinese with English abstract)

John, D.A., Ayuso, R.A., Barton, M.D., Blakely, R.J., Robert, J., Bodnar, J.H., Dilles, F.G., Fred T. Graybeal, John L., Mars, D.K., McPhee, R., Seal, Ryan D., Taylor. and Peter G. Vikre., 2010. Porphyry Copper Deposit Model, Chapter B of Mineral Deposit Models for Resource Assessment. U.S. Geological Survey, U.S.A, Report 2010–5070 B, 166 pp.

Johnson, M.C. and Rutherford, M.J., 1989. Experimental calibration of the aluminium-in-hornblende geobarometer with application to Long Valley caldera (California) volcanic rocks. Geology, 17(9): 837–841.

Leake, B.E., Woolley, A.R., Arps, C.E.S., Birch, W.D., Gilbert, M.C., Grice, J.D., Hawthorne, F.C., Kato, A., Kisch, H.J., Krivovichev, V.G., Linthout, K., Laird, J., Mandarino, J.A., Maresch, W.V., Nickel, E.H., Rock, N.M.S., Schumacher, J.C., Smith, D.C., Stephenson, N.C.N., Ungaretti, L., Whittaker, E.J.W. and Youzhi, G., 1997. Nomenclature of amphiboles: report of the subcommittee on amphiboles of the International Mineralogical Association, Commission on New Minerals and Mineral Names. Canadian Mineralogist, 35(1): 219– 246.

Li, S.R. and Santosh, M., 2014. Metallogeny and craton destruction: records from the North China Craton. Ore Geology Reviews, 56: 376–414.

Li, S.R., Santosh, M., Zhang, H.F., Luo, J.Y., Zhang, J.Q., Li, C.L., Song, J.Y. and Zhang, X.B., 2014. Metallogeny in response to lithospheric thinning and craton destruction: geochemistry and U–Pb zircon chronology of the Yixingzhai gold deposit, central North China Craton. Ore Geology Reviews, 56: 457–471.

Müntener, O., Kelemen, P.B. and Grove, T.L., 2001. The role of H2O during crystallization of primitive arc magmas under uppermost mantle conditions and genesis of igneous pyroxenites: an experimental study. Contributions to Mineralogy and Petrology, 141(6): 643–658.

Naney, M.T., 1983. Phase equilibria of rock-forming ferromagnesian silicates in granitic systems. American Journal of Science, 283(10): 993-1033.

O’Neill, H.S.C. and Pownceby, M.L., 1993. Thermodynamic data from redox reactions at high temperatures. I. An experimental and theoretical assessment of the electrochemical method using stabilized zirconia electrolytes, with revised values for the Fe-‘FeO’, Co-CoO, Ni-NiO, and Cu-Cu2O oxygen buffers, and new data for the W-WO2 buffer. Contributions to Mineralogy and Petrology, 114(3): 296–314.

Pirajno, F., 1992. Hydrothermal mineral deposits. Springer Verlag, Berlin Heidelberg, 703 pp.

Pletchov, P.Y. and Gerya, T.V., 1998. Effect of H2O on plagioclase-melt equilibrium. Experiment in Geosciences, 7(2): 7-9.

Preston, J. and Still, J., 2001. Mineral chemistry Spreadsheet V 15. Electronic internet publication, www.earth.ox.ac.uk/~davewa/pt/tools/formula.xls

Putirka, K.A., 2005. Igneous thermometers and barometers based on plagioclase plus liquid equilibria: tests of some existing models and new calibrations. American Mineralogist, 90(2-3): 336-346.

Rezaei, M., Zarasvandi, A., Azimzadeh, A.M. and Pourkaseb, H., 2015. Fluid inclusion petrography evaluation of Dalli porphyry copper-gold deposit using laser Raman spectroscopy analysis. 18th Symposium of the Geological Society of Iran, Tarbiat Modares University of Tehran, Tehran, Iran. (In Persian with English abstract)

Richards, J.P., 2003. Tectono-Magmatic Precursors for Porphyry Cu-(Mo-Au) Deposit Formation. Economic Geology, 98(8): 1515-1533.

Richards, J.P., 2005. Cumulative Factors in the Generation of Giant Calc-Alkalan Porphyry Cu Deposits. In: T.M. Porter (Editor), Super Porphyry Copper & Gold Deposits - A Global Perspective. PGC Publishing , Adelaide, pp. 7-25.

Richards, J.P., 2009. Postsubduction porphyry Cu-Au and epithermal Au deposits: Products of remelting of subduction-modified lithosphere. Geology, 37(3): 247-250.

Ridolfi, F., Renzulli, A. and Puerini, M., 2010. Stability and chemical equilibrium of amphibole in calc-alkaline magmas: An overview, new thermobarometric formulations and application to subduction-related volcanoes. Contributions to Mineralogy and Petrology, 160(1): 45–66.

Rowins, S.M., 2000. Reduced porphyry copper-gold deposits: A new variation on an old theme. Geology, 28(6): 491-494.

Schmidt, M.W., 1992. Amphibole composition intonalite as a function of pressure: An experimental calibration of the Al-in-hornblende baromete. Contributions to Mineralogy and Petrology, 110(2): 304-310.

Sillitoe, R.H., 1972. A Plate Tectonic Model for the Origin of Porphyry Copper Deposits. Economic Geology, 67(2): 184-197.

Sillitoe, R.H., 2010. Porphyry Copper Systems. Economic Geology, 105(1): 3-41.

Smith, J.V. and Brown, W.L., 1988. Feldspar Minerals. Crystal structures, physical, chemical, and microstructural properties. Springer-Verlag, New York. 809 pp.

Stein, E. and Dietl, C., 2001. Hornblende thermobarometry of granitoids from the Central Odenwald (Germany) and their implications for the geotectonic development of the Odenwald. Mineralogy and Petrology, 72(1): 185–207.

Sun, W., Huang, R.F., Li, H, Hu, Y.B., Zhang, C.C., Sun, S.J., Zhang, L.P., Ding, X., Li, C.Y., Zartman, R.E. and Ling. M.X., 2015. Porphyry deposits and oxidized magmas. Ore Geology Reviews, 65: 97–131.

Titley, S.R. and Beane, R.E., 1981. Porphyry copper deposits. Part 1. Geologic Setting, Petrology, and Tectogenesis. In: J.W.

Hedenquist, J.F.H. Thompson, R.J. Goldfarb and J.P. Richards (Editors), Economic Geologists, 75th Anniversary Volume. Society of Economic Geologists, U.S.A, pp. 214-234.

Wang, R., Richards, J.P., Hou, Z.Q., Yang, Z.M., Gou, Z.B. and DuFrane, A., 2014. Increasing Magmatic Oxidation State from Paleocene to Miocene in the Eastern Gangdese Belt, Tibet: Implication for Collision-Related Porphyry Cu-Mo ±Au Mineralization. Economic Geology, 109(7): 1943–1965.

Whitney, J.A., 1975. Volatiles in magmatic systems, in Fluid-mineral equilibria in hydrothermal systems. Reviews in Economic Geology, 1: 155-175.

Whitney, D.L. and Evans, B.W., 2010. Abbreviations for names of rock-forming minerals. American Mineralogist, 95(1): 185-187.

Whitney, J.A. and Storme jr, J.C., 1985. Mineralogy, petrology, and magmatic conditions from the Fish Canyon Tuff, central San Juan volcanic field, Colorado. Journal of Petrology, 26(3): 726-762.

Wilkinson, J.J., 2001. Fluid inclusions in hydrothermal ore deposits. Lithos, 55: 229-272.

Yoder, H.S. and Tilley, G.E., 1962. Origion of basalt magmas: an experimental study of natural and synthetic rock systems. Journal of Petrology, 3(3): 342-532.

Zarasvandi, A. and Liaghat, S., 2005. Discrimination of Productive and Nonproductive Porphyritic Intrusions in the South of Khezr-Abad area, Yazd: Using by REE Geochemistry. Proceeding of 9th symposium of Geological Society of Iran, Kharazmi University of Tehran, Tehran, Iran. (In Persian with English abstract)

Zarasvandi, A., Rezaei, M., Sadeghi, M., Lentz, D., Adelpour, M. and Pourkaseb, H., 2015a. Rare earth element signatures of economic and sub-economic porphyry copper systems in Urumieh–Dokhtar Magmatic Arc (UDMA), Iran. Ore Geology Reviews, 70: 407-423.

Zarasvandi, A., Rezaei, M., Raith, J., Lentz, D., Azimzadeh, A.M. and Pourkaseb, H., 2015b. Geochemistry and fluid characteristics of the Dalli porphyry Cu–Au deposit, Central Iran. Journal of Asian Earth Sciences, 111: 175-191.

Zhong, J., Chen, Y., Pirajno, F., Chen, J., Li, J., Qi, J. and Li, N., 2014. Geology, geochronology, fluid inclusion and H–O isotope geochemistry of the Luoboling Porphyry Cu–Mo deposit, Zijinshan Orefield, Fujian Province, China. Ore Geology Reviews, 57: 61–77.