Tectono-magmatic characteristics of Bagham pluton in southeastern Ardestan: Base on mineral chemistry of clinopyroxene and amphibole

Abstract

Gabbroic pluton of Bagham is located in southeastern Ardestan and has intruded into Eocene volacanic rocks. The study area is a part of Central Iranian zone and Urumieh-Dokhtar magmatic belt. Clinopyroxene, plagioclase and amphibole are main minerals in the pluton. Mineral chemistry studies show that clinopyroxenes are augite and are plotted in almost medium pressure field. The clinopyroxene composition yields the crystallization temperatures that range from 840°C to 920°C. In tectonic setting diagrams, clinopyroxenes is plotted in orogenic field and related to magmatic arc. Amphiboles plot in the field of calcic amphiboles and are magnesiohornblende. Tectono-magmatic study indicates a sub alkaline nature for the pluton. The coexisting amphibole-clinopyroxene geothermometer shows the temperatures range from 730 to 790 °C. Plagioclases are only felsic mineral in the gabbros. The mineral chemistry of plagioclases shows bytonite (core), labradorite - andesine (rim) and albite (results of saussuritization) fields.

Keywords


[1] Nisbet E. G., Pearce J. A., "Clinopyroxene composition of mafic lavas from different tectonic settings", Contributions to Mineralogy and Petrology 63 (1977) 161-173.

[2] Beccaluva L., Maccciotta G., Piccardo G. B., Zeda O., "Clinopyroxene composition of ophiolite basalts as petrogenetic indicator", Chemical Geology 77 (1989) 165-182.

[3] Anderson J. L., Smith D. R., "The effect of temperature and oxygen fugacity on Al-in-‎hornblende barometry", American Mineralogist 80 (1995) 549-559‎‌.‌

[4] Spear F. S., "Amphibole-plagioclase equilibria: an empirical model for the reaction albite + tremolite = edenite + 4 quartz", Contribution to Mineralogy and Petrology 77 (1981) 355-364.

[5] Hammarstrom J. M., Zen E., "Aluminum in hornblende: An empirical ipeous geobarometer. American Mineralogist", 71(1986) 1297 -1313.

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

[7] Johnson M. C., Rutherford M. J., "Experimental calibration of the aluminum-in-hornblende geobarometer with application ‎to Long Valley caldera (California) volcanic rocks", Geology 17 (1989) 837-841‎‌.‌

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

[9] Schmidt M. W., "Amphibole composition in tonalite as a function of pressure: an experimental calibration of the Al-in-hornblende barometer", Contributions to Mineralogy and Petrology 110 (1992) 304–310.

[10] Lindsley I., "Pyroxene thermometry", American Mineralogist 68 (1983) 477-493.‎

[11] Ulrych J., Cimbalnikova A., Fiala L., Kaspar P., Lang M., Minarik L., Palivcova M., Pivec E., "Petrology of the Petrovice melagabbro", Rozpr Cs Akad Ved R Mat Prir Ved, Academia, Praha (1976) 57.

[12] Abu Anbar M., "Petrogenesis of the Nesryin gabbroic intrusion in SW Sinai, Egypt: new contributions from mineralogy, geochemistry, Nd and Sr isotopes", Mineralogy and Petrology 95 (2009) 87–103.

[13] Stocklin J., "Possible ancient continental margine in Iran .In: Burk C.A. and Drak C. L. (Eds).The Geology of Continental Margines", Springer, New York (1974) 873-887.

]14[ نبوی م. ح.، "دیباچه‌ایی بر زمین‌شناسی ایران"، سازمان زمین‌شناسی ایران، (1355) 109 ص.

]15[ درویش‌زاده ع.، زمین شناسی ایران. انتشارات امیر کبیر (1370)، 901ص

[16] Pourhosseini F., "Petrogenesis of Iranian plutons: a study of the Natanz and Bazman intrusive complexes", PhD thesis, University of Cambridge (1981) 315p.

[17] Amidi S. M., "Contribution á l’étude stratigraphique, petrologique et petrographique des roches magmatiques de la region Natanz-Nain-Surk (Iran central)", Thèse Ph.D., Univ. Grénoble, France (1975) 316pp.

[18] Amidi S. M., "Étude géologique de la région de Natanz-Surk (Iran Central), stratigraphie et pétrologie", Geology Survey of Iran 42 (1977) 316 p.

[19] Reyre D., Mohafez S., "Une premie`re contribution des accords NIOC-ERAP á laconnaissance géologique de l’Iran", Revue de l’Institut Franc¸ais du Pétrole 25 (1981) 979–1014.

]20[ رادفر ج.، "نقشه چهارگوش زمین شناسی 1:100000 اردستان"، سازمان زمین شناسی و اکتشافات معدنی کشور، 1378.

[21] Dachs E., "PET: Petrological elementary tools for mathematica: an update", Computers and Geoscience 30 (1981) 173-182.

[22] Droop G.T.R., "A general equation for estimating Fe+3 concentrations. in ferromagnesian silicates and oxides from microprobe analyses, using stoichiometric criteria", Mineralogical Magazine 51(1987) 431-435.

[23] Morimoto N., "The nomenclature of pyroxenes", Mineralogical Magazine 52 (1988) 535–50.

[24] Berger J., Féménias O., Mercier J. C. C., Demaiffe D., "Ocean-floor hydrothermal metamorphism in the Limousin ophiolites (western French Massif Central): evidence of a rare preserved Variscan oceanic marker", Journal of Metamorphic Geology. 23b(2005) 795-812.

[25] Kushiro I., "Si-Al relation in clinopyroxenes from igneous rocks", American Journal of Scince 258 (1960) 548-554.

[26] Le Bas M. J., "The role of aluminium in igneous clinopyroxenes with relation to their parentage", American Journal of Scince 260 (1962) 267-288.

[27] Bence A. E., Papike J. J., Ayuso R. A., "Petrology of Atlantic island arcs", Bulletin of ‎Volcanology 32 (1975) 189-206.‎

[28] Schweitzer E. L., Papike, J. J., Bence E., "Statistical analysis of clinopyroxenes from ‎deep-sea basalts", American Mineralogist 64 (1979) 501-513.

[29] Gamble R. P., Taylor L. A., "Crystal/liquid partitioning augite: effects of cooling rate", Earth and Planetary Science Letters 47 (1980) 21-33.

[30] Mahood G. A., Baker D. R., "Experimental constraints on depths of fractionation of mildly alkalic basalts and associated felsic rocks: Pantelleria, strait of Sicily", Contribution to Mineralogy and Petrology 93 (1986) 251–264.

[31] Aoki K., Shiba I., "Pyroxene from lherzolite inclusions of Itinomegata Japan", Lithos 6 (1973) 41–51.

[32] Letterrier J., Maury R. C., Thonon P., Girard D., Marchal M., "Clinopyroxene composition as a method of identification of the magmatic affinities of paleo-volcanic series", Earth and Planetary Science Letters 59 (1982) 139–54.

[33] Loucks, R. R., "Discrimination of ophiolitic from nonophiolitic ultramafic-mafic allochthons in orogenic belts by the Al/Ti ratio in clinopyroxene", Geology 18 (1990) 346–349.

[34] Molina J. F., Scarrow J.H., Montero P.G., "High-Ti amphibole as a petrogenetic indicator of magma chemistry: evidence for mildly alkalic-hybrid melts during evolution of Variscan basic–ultrabasic magmatism of Central Iberia", Contribution to Mineralogy and Petrology 158 (2009) 69–98

[35] Leake B. E., "Nomenclature of amphiboles, Report of the subcommittee on amphiboles of the International Mineralogical Association on new minerals and mineral names", European Journal of Mineralogy 9 (1997) 623-651.