Kharazmi Journal of Earth Sciences

Kharazmi Journal of Earth Sciences

Investigation of metamorphic conditions and mineralogical changes at green-schist to amphibolite facies transition zone using phase diagrams and compositions of the mineral: a case study from the Kordestan province metabasites

Author
Mirmohammad Miri
Shahid Chamran University of Ahvaz
Abstract
In this paper, metamorphic conditions (T, P and fluid composition) in greenschist to amphibolite facies transition zone are investigated using textural evidence, composition of the minerals and phase diagrams. Metabasites from the south of Kordestan Province were metamorphosed from sub-greenschist to upper amphibolite facies. Field observations and petrography studies show that there are some rocks containing mineral assemblage hornblende + plagioclase + epidote + quartz formed in conditions intermediate between greenschist and amphibolite facies. Electron microprobe analysis and scanning electron microscopy images reveal that the amphiboles have chemical zoning with actinolite cores and hornblende rims and these chemical changes are discontinous. The plagioclases are commonly oligoclase but there is some remnant albite. The epidotes are enriched in Fe with low clinozoisite contents. Geothermobarometry calculations using the amphibole compositions represent 423 °C and 2 kbar for the cores and 543 oC and 4 kbar for the rims. The calculated phase diagram based on whole-rock composition of a sample indicates that it was formed in 450 to 550 °C and 2.1 to 6.8 kbar that fall in the field of epidote-amphibolite facies condition. The O2 and CO2 vs. T variation phase diagrams show that O2 had a significant role formation of the mineral assemblage but the fluid contained very low CO2. Chemical discontinuities in the amphiboles and the plagioclases with different compositions demonstrate that the studied rocks formed in disequilibrium conditions.
Keywords
Metabasit
Greenschist
Amphibolite
Phase diagram
Kordestan
Subjects
ترکیان، ا.، ایزدیار، ج.، رضوانی مکبر، ز.، سپاهی، ع. ا.، "سنگ‌نگاری و کاربرد شیمی بلور در بررسی‌های ترمودینامیکی سنگ‌های دگرگونی، منطقه زرینه، جنوب قروه- کردستان". مجله بلورشناسی و کانی شناسی ایران، دوره ۲۵، شماره ۴ (1398) صفحات ۷۸۶-۷۷۵.
شیخ ذکریایی، ج.، منصف، ا.، "کانی شناسی - پتروفابریک مجموعه دگرگونی قروه (شمال غرب ایران)"، مجله علوم پایه دانشگاه آزاد اسلامی، دوره 20 ، شماره 77 (1389)، صفحه 203 تا 220.
عمرانی، ه.، "مطالعه دگرگونی و دگرشکلی سنگ های جنوب و جنوب قروه، استان کردستان"، پایان نامه کارشناسی ارشد، دانشگاه تبریز، (1384).
میری، م، م.، "شیمی کانی، ترموبارومتری و تحول دگرگونی آمفیبول شیست ها و آمفیبولیت های مناطق قروه و همدان"، پایان نامه دکتری، دانشگاه بوعلی سینا، (1395).
Azizi, H., Nouri, F., Stern R. J., Azizi, M., Lucci, F., Asahara, Y., Zarinkoub, M.H., Chung, S. L., New evidence for Jurassic continental rifting in the northern Sanandaj Sirjan Zone, western Iran: the Ghalaylan seamount, southwest Ghorveh. International Geology Review, 62 (2020) 1–23.
Azizi, H., Stern, R.J. "Jurassic igneous rocks of the central Sanandaj–Sirjan zone (Iran) mark a propagating continental rift, not a magmatic arc", Terra Nova. 31 (2019) 415-423.
Begin, N., “Contrasting mineral isograd sequences in metabasites of the Cape Smith Belt, northern Quebec, Canada: three new bathograds for mafic rocks”. Journal of Metamorphic Geology, 10 (1992) 685–704.
Berberian, F., Berberian, M., "Tectono-plutonic episodes in Iran", In: Zagros, Hindukush, Himalaya Geodynamic Evolution, Eds. Gupta, H.K., Delany, F.M., AGU, (1981) 5–32.
Berberian, M. King, G., "Towards a paleogeography and tectonic evolution of Iran", Canadian Journal of Earth Sciences, 18 (1981) 210–265.
Bucher, K., Grapes, R., "Petrogenesis of metamorphic rocks. Springer", (2011) 428p.
Bushmin, S.A., Glebovitsky, V.A., "Scheme of Mineral Facies of Metamorphic Rocks", Geology of Ore Deposits, 50 (2008), 659-669.
Connolly, J.A.D., "Computation of phase equilibria by linear programming: A tool for geodynamic modeling and its application to subduction zone decarbonation", Earth and Planetary Science Letters, 236 (2005), 524–541.
Deer, W.A., Howie, R.A., Zussman, J., "Rock forming minerals, volume4A, framework silicates". Wiley, (1963), 992p.
Ghasemi, A., Talbot, C.J., "A new tectonic scenario for the Sanandaj–Sirjan Zone (Iran)", Journal of Asian Earth Science, 26 (2006) 683–693.
Graham, C.M., "Metabasite amphiboles of the Scottish Dalradian". Contributions to Mineralogy and Petrology, 47 (1974) 165–185
Grapes, R.H., Hoskin P.W.O. "Epidote Group Minerals in Low–Medium Pressure Metamorphic Terranes", Reviews in Mineralogy and Geochemistry, 56 (2004) 301-345.
Grapes, R.H., "Actinolite-Hornblende Pairs in Metamorphosed Gabbros, Hidaka Mountains, Hokkaido", Contributions to Mineralogy and Petrology, 49 (1975), 125-140.
Green, E.C.R., White, R.W., Diener, J.F.A., Powell, R., Holland, T.J.B., Palin, R.M., "Activity-composition relations for the calculation of partial melting equilibria in metabasic rocks", Journal of Metamorphic Geology, 34 (2016), 845-869.
Gutiérrez-Aguilar, F., Schaaf, P., Solís-Pichardo, G., Arrieta-García, G., Hernández-Treviño, T., Linares-López, C., "Phase equilibrium modelling of the amphibolite facies metamorphism in the Yelapa-Chimo Metamorphic Complex, Mexico", Geoscience Frontiers, 12 (2021) 293-312.
Hassanzadeh, J., Wernicke, B., "The Neotethyan Sanadaj–Sirjan zone of Iran as an archetype for passive margin–arc transitions". Tectonics, 35 (2016) 586–621.
Hawthorn, F.C., Oberti, R., "Classification of the amphiboles", Reviews in Mineralogy and Geochemistry 67 (2007) 55–88.
Hawthorne, F.C., "The Crystal Chemistry of the Amphiboles", Canadian Mineralogist, 21, (1983) 173–480.
Holland, T. J. B., Powell, R., "Activity-composition relations for phases in petrological calculations: an asymmetric multicomponent formulation", Contributions to Mineralogy and Petrology 145 (2003) 492-501.
Holland, T. J. B., Powell, R., "An improved and extended internally consistent thermodynamic dataset for phases of petrological interest, involving a new equation of state for solids", Journal of Metamorphic Geology, 29 (2011) 333 – 383.
Hollister, L.S., Grissom, G.C., Peters, E.K., "Confirmation of the empirical correlation of Al in hornblende with pressure of solidification of calc-alkaline plutons," American Mineralogist, 72 (1987) 231–239.
Hosseini, M., "Geological map of Qorveh, 1:100000", Geological Survey of Iran, (1999).
Laird, J., "Phase relations of metamorphic amphiboles; natural occurrence and theory; amphiboles in metamorphosed basaltic rocks; greenschist facies to amphibolite facies", Reviews in Mineralogy and Geochemistry 9 (1982) 113–138.
Laird J., Albee A.L., "Pressure, temperature, and time indicators in mafic schist: their application to reconstructing the polymetamorphic history of Vermont". American Journal of Science, 281 (1981) 127-175.
Maruyama, S., Liou, J.G., Suzuki, K., "The peristerite gap in low-grade metamorphic rocks". Contributions to Mineralogy and Petrology, 81 (1982) 268–276.
Miri, M., Sepahi, A., Aliani, F., Maanijou, M., "Chemical Zoning of Ca-Amphiboles in Amphibolites, from the Hamedan Area, West Iran", Arabian Journal of Geosciences 9 (2016) 13:619.
Miyashiro, A., "Volcanic Rock Series in Island Arcs and Active Continental Margins", American Journal of Science, 274 (1974) 321-355.
Mohajjel, M., Fergusson, C.L., "Jurassic to Cenozoic tectonics of the Zagros Orogen in northwestern Iran", International Geology Reviews, 56 (2014) 263–287.
Oba, T.U, Yagi, K., "Phase Relations on the Actinolite-Pargasite Join", Journal of Petrology 281 (1987) 23–36.
Oba, T., "Phase relations in the tremolite-pargasite join", Contribution to Mineralogy and Petrology 71(1980) 247–256
Oliveira, D.P., Wiechowski, A., Robb, L., Inverno, C., "Amphibolite vs. banded amphibolite: a case study in the São Martinho-Arronches area, Tomar Cordoba Shear Zone, NE Ossa Morena Zone, Portugal", Cadernos Lab. Xeolóxico de Laxe, 28 (2003) 213-229.
Ríos, C., "Cation substitutions governing the chemistry of amphibole in the Silgará Formation metabasites at the southwestern Santander Massif", Boletín de Geología UIS, 27 (2005), 13-30.
Robinson, P., Spear, F.S., Schumacher, J.C., Laird, J., Klein, C., Evans, B.W., Doolan, B.L., "Phase relations of metamorphic amphiboles: Natural occurrence and theory", In: Amphiboles: Petrology and Experimetal Phase Relations, Eds. Veblen D.R., Ribbe P.H., Reviews in Mineralogy, 9 (1982), 1-227.
Sartibi, A.H., "Geological map of Sanandaj, 1:100000", Geological Survey of Iran, (2005).
Schumacher, J.C., "Metamorphic amphiboles: composition and coexistence", Reviews in Mineralogy and Geochemistry, 67 (2007) 359–416.
Schumacher, R., (1991) "Compositions and phase relations of calcic amphiboles in epidote- and clinopyroxene-bearing rocks of the amphibolite and lower granulite facies, central Massachusetts, USA Renate Schumacher", Contributions to Mineralogy and Petrology, 108 (1991) 196-211
Smelik, E.A., Veblen, D.R., "Exsolution of cummingtonite from glaucophane - a new orientation for exsolution lamellae in clinoamphiboles". American Mineralogist 76 (1991) 971-984.
Starr, P., "Sub-Greenschist to Lower Amphibolite Facies Metamorphism of Basalts: Examples from Flin Flon, Manitoba and Rossland, British Columbia", Phd thesis, University of Calgary (2017).
Starr, P.G., Pattison, D.R.M., "Equilibrium and disequilibrium processes across the greenschist–amphibolite transition zone in metabasites", Contributions to Mineralogy and Petrology, (2019) 174:18.
White, R.W., Powell, R., Holland, T.J.B., Johnson, T.E., Green, E.C.R., "New mineral activity-composition relations for thermodynamic calculations in metapelitic systems", Journal of Metamorphic Geology, 32 (2014) 261-286.
Whitney, D.L. Evans, B.W., "Abbreviations for names of rock-forming minerals", American Mineralogist, 95 (2010) 185-187.
Yavuz, F., " WinAmphcal: A Windows program for the IMA04 amphibole classification", Geochemistry, Geophysics, Gcosystems, 8 (2007) 1-12.
Zenk, M., Schulz, B., "Zoned Ca-amphiboles and related P-T evolution in metabasites from the classical Barrovian metamorphic zones in Scotland", Mineralogical Magazine, 68 (2004) 769–786.
Zingg, A.J., "Immiscibility in Ca-amphiboles", Journal of Petrology, 37 (1996) 471- 496.
Kharazmi Journal of Earth Sciences
Volume 8, Issue 1 - Serial Number 15
September 2022
Pages 47-74