تعیین دمای تشکیل، فوگاسیته اکسیژن و نسبت Ce4+/Ce3+ با استفاده از شیمی زیرکن دردایک¬های پگماتیتی ملاير- بروجرد- شازند، پهنه سنندج-سیرجان
محورهای موضوعی :
1 - دانشگاه خوارزمی
کلید واژه: شیمی زیرکن# دایک¬های پگماتیتی# ضریب توزیع# عناصر نادرخاکی# فوگاسیته اکسیژن# پهنه سنندج- سیرجان#,
چکیده مقاله :
پلوتون های گرانیتوئیدی در پهنه سنندج-سیرجان میزبان دایک های پگماتیتی متعددی هستند. این پژوهش بر روی مطالعه شیمی کانی زیرکن در دایک های پگماتیتی گستره ملایر، بروجرد و شازند به منظور ارزیابی دمای تبلور زیرکن، فوگاسیته اکسیژن و نسبت Ce4+/Ce3+ و همچنین تعیین ضریب توزیع عناصر نادر خاکی، عناصر اورانیوم، توریوم، تالیم، نیوبیم و ایتریم متمرکز شده است. نمودارهای متمایزکننده گرانیتوئیدها از جمله Th در برابر Y و Yb/Sm در برابر Y و Nb، نشان داد، زیرکن های مورد مطالعه در گستره سنگ های سینیت پگماتیت قرار دارند. ضریب توزیع زیرکن/ سنگ کل نشان داد، بلورهای زیرکن غنی شدگی نسبت HREE به LREE دارند. شیمی زیرکن نشان داد، دایک های پگماتیتی ملایر و شازند دارای مقادیر Hf کمتر و تغییرات کمتر در REE نسبت به زیرکن های دایک پگماتیت بروجرد هستند که نشان‌دهنده نقش فرایندهای هیدروترمالی بعدی در تشکیل زیرکن های بروجرد است. دمای تبلور، فوگاسیته اکسیژن و نسبت های Ce4+/Ce3+ از دایک پگماتیتی ملایر به شازند و در نهایت بروجرد کاهش یافته است. شرایط احیایی ماگماتیسم، مقدار Th/U کمتر از یک و مقدار Y/Ho بالای 20 نشان می دهد، بنابراین این پگماتیت ها از لحاظ کانی سازی عقیم هستند.
The Granitoid plutons in the Sanandaj-Sirjan zone host numerous pegmatitic dikes. This study is focused on mineral chemistry of zircons in the pegmatite dikes in the Malayer, Boroujerd and Shazand district to evaluate zircon crystallization temperature, oxygen fugacity and Ce4+/Ce3+ ratio and also zircon/rock partition coefficients of REEs and U, Th, Ta, Nb and Y. Trace element discrimination digrams such as Th versus Y and Yb/Sm versus Y and Nb, indicated studied zircons were located in the syenite pegmatite field. Zircon/rock partition coefficients indicate that zircon granis are enriched in the HREE than LREE. Zircon chemistry show that zircon in the Shazand and Malayer pegmatite dikes have more Hf and less REE distribution than zircons in the Boroujerd pegmatite dikes. Consequently, it indicates the role of latter hydrothermal process in the formation of Boroujerd zircons. Crystallization temperature, oxygen fugacity and Ce4+/Ce3+ ratios decrease from Malayer to Shazand and finally Boroujerd pegmatite dikes. Reduced condition of magmatism, Th/U contents below 1 and Y/Ho content higher than 20 indicate that these pegmatities are barren.
Bau, M., 1996. Controls on the fractionation of isovalent trace elements in magmatic and aqueous systems: evidence from Y/Ho, Zr/Hf, and lanthanide tetrad effect. Contributions to Mineralogy and Petrology, 123, 323–333.
Ballard, J.R., Palin, M.J. and Campbell, I.H., 2002. Relative oxidation states of magmas inferred from Ce(IV)/Ce(III) in zircon: application to porphyry copper deposits of northern Chile. Contribution to Mineralogy and Petrology, 144, 347–364.
Belousova, E.A., Griffin, W.L. and O'Reilly, S.Y., 2006. Zircon crystal morphology, trace element signatures and Hf isotope composition as a tool for petrogenetic modelling: examples from Eastern Australian granitoids. Journal of Petrology, 47, 329–353.
Belousova, E.A., Griffin, W.L., O'Reilly, S.Y. and Fisher, N.I.I., 2002. Igneous zircon: trace element composition as an indicator of source rock type. Contribution to Mineralogy and Petrology, 143, 602–622.
Blundy, J.D. and Wood, B.J., 1994. Prediction of crystal-melt partition coefficients from elastic moduli. Nature 372, 452–454.
Cabral, A.R. and Zeh, A., 2015. Detrital zircon without detritus: a result of 496 Ma-old fluid–rock interaction during the gold-lode formation of Passagem, Minas Gerais, Brazil. Lithos, 212–215, 415–427.
Claiborne, L.L., Miller, C.F., Walker, B.A., Wooden, J.L., Mazdab, F.K. and Bea, F., 2006. Tracking magmatic processes through Zr/Hf ratios in rocks and Hf and Ti zoning in zircons: an example from the Spirit Mountain batholith, Nevada. Mineralogy Magazine 70, 517–543.
Corfu, F., Hanchar, J.M., Hoskin, P.W.O. and Kinny, P., 2003. Atlas of zircon textures. In: Hanchar JM, Hoskin PWO (Eds). Review in Mineralogy and Geochemistry, 53, 469–500.
El-Bialy, M. Z. and Ali, K. A., 2013. Zircon Trace Element Geochemical Constraints on the Evolution of the Ediacaran (600–614 Ma) Post-Collisional Dokhan Volcanics and Younger Granites of SE Sinai, NE Arabian-Nubian Shield. Chemical Geology, 360/361, 54–73.
Ferry, J.M. and Watson, E.B., 2007. New thermodynamic models and revised calibrations for the Ti-in-zircon and Zr-in-rutile thermometers. Contribution to Mineralogy and Petrology, 154, 429–437.
Ghasemi Siani, M., Mehrabi, B., Bayat, S., Neubauer, F. and Cao, Sh., 2021. Geochronology, geochemistry and mineral chemistry of Malayer–Boroujerd–Shazand pegmatite dikes, Sanandaj–Sirjan zone, NW Iran. International Journal of Earth Sciences. Doi: 10.1007/s00531-021-02009-9.
Harrison, T.M., Watson, E.B. and Aikman, A.B., 2007. Temperature spectra of zircon crystallization in plutonic rocks. Geology, 35, 635–638.
Hofmann, A.E., Baker, M.B. and Eiler, J.M., 2014. Sub-micron-scale trace element distributions in natural zircons of known provenance: implications for Ti-in-zircon thermometry. Contribution to Mineralogy and Petrology, 168, 1057.
oskin, P.W.O., 2005. Trace-element composition of hydrothermal zircon and the alteration of Hadean zircon from the Jack Hills, Australia. Geochimica et Cosmochimica Acta, 69, 637–648.
Hoskin, P.W.O. and Schaltegger, U., 2003. The composition of zircon and igneous and metamorphic petrogenesis. Reviews in Mineralogy and Geochemistry, 53, 27–62.
Krauskopf, K.B., 1979. Introduction to Geochemistry. McGraw-Hill, New York. 721.
Linnen, R.L. and Keppler, H., 1997. Columbite solubility in granitic melts: consequences for the enrichment and fractionation of Nb and Ta in the earth's crust. Contributions to Mineralogy and Petrology, 128, 213–227.
Nardi, L.V.S., Formoso, M.L.L., Müller, I.F., Fontana, E., Jarvis, K. and Lamarão, C., 2013. Zircon/rock partition coefficients of REEs, Y, Th, U, Nb, and Ta in granitic rocks: Uses for provenance and mineral exploration purposes. Chemical Geology, 335, 1–7.
Nasdala, L., Hanchar, J.M., Rhede, D., Kennedy, A.K. and Váczi, T., 2010. Retention of uranium in complexly altered zircon: an example from Bancroft, Ontario. Chemical Geology, 269, 290–300.
Pettke, T., Audetat, A., Schaltegger, U. and Heinrich, C.A., 2005. Magmatic-to hydrothermal crystallization in the W-Sn mineralized mole granite (NSW, Australia)—part II: evolving zircon and thorite trace element chemistry. Chemical Geology, 220,191–213.
Rubatto, D. and Hermann, J., 2007. Experimental zircon/melt and zircon/garnet trace element partitioning and implications for the geochronology of crustal rocks. Chemical Geology, 241, 38–61.
Schaltegger, U., 2007. Hydrothermal zircon. Elements, 3, 51.
Sepahi, A.A., Salami, S., Lentz, D.R., McFarlane, C. and Maanijou, M., 2018. Petrography, geochemistry, and U-Pb geochronology of pegmatites and aplites associated with the Alvand intrusive complex in the Hamedan region, Sanandaj-Sirjan zone, Zagros orogen (Iran). International Journal of Earth Science, 107(3), 1059–1096.
Sepahi, A.A., Vahidpour, H., Lentz, D.R., McFarlane, C.R., Maanijou, M., Salami, S., Miri, M., Mansouri, M. and Mohammadi, R., 2020. Rare sapphire-bearing syenitoid pegmatites and associated granitoids of the Hamedan region, Sanandaj-Sirjan zone, Iran: analysis of petrology, lithogeochemistry and zircon geochronology/trace element geochemistry. Geological Magazine, 157(9), 1499–1525. Doi: 10.1017/S0016 75682 00000 23.
Shannon, R.D., 1976. Revised effective ionic radii and systematic studies of inter-atomic distances in halides and chaleogenides. Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials 32, 751–767.
Smythe, D.J. and Brenan, J.M., 2016. Magmatic oxygen fugacity estimated using zircon-melt partitioning of cerium. Earth and Planetary Science Letters 453, 260–266.
Sun, S.S. and McDonough, W.F., 1989. Chemical and isotopic systematic of oceanic basalts. Implications for mantle composition and processes. In: Saunders, A.D., Norry, M.J. (Eds.). Magmatism in the Ocean Basins. Geological Society, London, Special Publications 42, 313–345.
Trail, D., Watson, E.B. and Tailby, N.D., 2012. Ce and Eu anomalies in zircon as proxies for the oxidation state of magmas. Geochimica et Cosmochimica Acta, 97, 70–87.
Trail, D., Watson, E.B. and Tailby, N.D., 2011. The oxidation state of Hadean magmas and implications for early Earth's atmosphere. Nature, 480, 79–82.
Virgo, D., Mysen, B.O. and Kushiro, I., 1980. Anionic constitution of 1-atmosphere silicate melts: implications for the structure of igneous melts. Science 20, 1371–1373.
Wang, X., Griffin, W.L. and Chen, J., 2010. Hf contents and Zr/Hf ratios in granitic zircons. Geochemical Journal 44, 65–72.
Watson, E.B., Wark, D.A. and Thomas, J.B., 2006. Crystallization thermometers for zircon and rutile. Contribution to Mineralogy and Petrology, 151, 413–433.
Zeh, A., Gerdes, A., Will, T.M. and Frimmel, H.E., 2010. Hafnium isotope homogenization during metamorphic zircon growth in amphibolite-facies rocks: examples from the Shackleton Range (Antarctica). Geochimica et Cosmochimica Acta, 74, 4740–4758.
