Mineralogy and mineral – chemistry of tourmaline and garnet from Molataleb village granitoid (North of Aligudarz) NW of Isfahan

Abstract

The Middle Jurassic granitoids from Molataleb village lie in the Sanandaj-Sirjan zone. This body located, NW of Isfahan, and is predominately composed of tonalites and two-mica peraluminous granodiorites cross cut Jurassi (Liass-Dogger) shales and slates. Tourmaline and garnet are among significant minor minerals of the granodiorites. Subhedral to anhedral tourmaline with pleochroic brown-green to blue color occurs as small amount among other minerals of these rocks. On the bases of chemical data as wall as geochemical diagrams, the studied tourmalines are characterized by weak chemical zoning, more Mg than Fe and deravite in composition. The content of other end members (schorlite, uvite, foitite) is insignificant. Mg- tourmalines, are associated with metamorphic or metasomatic assemblages. The origin of these minerals is likely related to meta-sedimentary rocks (i.e. meta-pelites and meta-psammites) coexisting with a Al-saturated phase.  The studied garnets are anhedral, rimmed and cross cut by veins contain small crystals of biotite and muscovite. In few cases, both biotite and muscovite are found in investigated garnets. Locally, garnets are surrounded by chlorite crystals. Chemically, the garnet is almandine with a rim relatively enriched in spessartine and fairly depleted in pyrope. The revers zoning is characteristic of high grade-metamorphic garnet and point to its crystallization in a low-pressure system. The high content of Mn in residual liquids derived from the crystallization of magma, caused the stability of garnet. On the bases of available data, the pelitic deposits (Lower Jurassic), have been subjected to progressive regional metamorphism (upper amphibolite – lower granulite) followed by partial melting of meta-pelites. The studied garnets (Fe-Mg phases) formed at or near the climax of metamorphism.

Keywords


[1] اتردی س. "کان‍‍‍‍‍ی شناس‍‍‍‍‍ی س‍‍‍‍‍یل‍‍‍یکات ها"، انتشارات دانشگاه پ‍‍‍‍‍یام نور (1378) 291.

[2] Henry D.J., Guiditti C.V., “Tourmaline as a petrogenetic indicator mineral: an example from the staurolite grade metapelites of NW-Marine”, American Mineralogist, 70 (1985) 1-15.

[3] Harraz H. Z., El-Sharkawy M. F., “Origin of tourmaline in the metamorphosed Sikait pelitic belt, south eastern desert, Egypt”, Journal of African Earth Sciences, 33 (2001) 391-416.

[4] Deer W.A., Howie R.A., Zussman J., “Rock forming mineral”, Longman, (1) (1966) 333.

[5] London D., Manning D.A.C., “Chemical variation and significance of tourmaline from SW England”, Economic Geology, 90 (1995) 495–519.

[6] Novak M., Povandra P., Selway J.B., “Schorl–oxy–schorl to dravite–oxy–dravite tourmaline from granitic pegmatite, examples from the Moldanubicum, Czech Republic”, Europian Journal of Mineralogy, 16 (2004) 323-333.

[7] Bernard F., Moutou P., Pichavant M., “Phase relation of tourmaline leucogranites and the significance of tourmaline in silicic magma" Journal of Geology, 93 (1985) 271-291.

[8] Clemens J.D., Wall V.J., “Origin and crystallization of some peraluminous (S-type) ranitic Magmas”, Contribution to Mineralogy and Petrology, 19 (1981) 111-131.

[9] Brich W.D., Andrew J., Gleadow W., “The genesis of garnet and cordierite in acid volcanic rocks, Central Victoria, Australia”, Contribution to Mineralogy and Petrology, 45 (1974) 1-13.

[10] Thiele O., Alavi M., Assefi R., Hushmand–Zadeh A., Seyed–Emami K., Zahedi M., "Explanatory text of the Golpayegan quadrangle map. 1:250000”, Geological Survey Iran, (1968) 3-24.

[11] عبداللهی ش.، "مطالعه‌ی پترولوژی توده نفوذی روستای ملاطالب (شمال الیگودرز) پهنه ی سنندج- سیرجان"، پایان نامه کارشناسی ارشد دانشگاه اصفهان (1388) 124.

[12] Chappell B.W., white A.J.R., “Two contrasting granite types”, Pacific Geology 8 (1974) 173-174.

[13] Kretz R., “Symbols for rock-forming minerals”, Americam Mineralogists 68 (1983) 277-279

[14] Hawthoren F.C., Henry D.J., “Classification of the mineral of the tourmaline group”, Europian Journal of Mineralogy, 11 (1999) 201-215.

[15] Hawthoren F.C., “Bond–valance constraints on the chemical composition of tourmaline”, Canadian Mineralogists, 40 (2002) 789-797.

[16] Collins A.C., “Mineralogy and geochemistry of tourmaline in contrasting hydrothermal system, Coplapo area, Northern Chile”, PhD Thesis, Faculty of Geoscience University of Arizona (2010).

[17] Einaudi M.T., Meinert L.D., Meinert R.J., “Newberry skarn deposit”, Economic Geology, 75th Anniversary special volume (1981) 317-391.

[18] Atherton M.P., “The variation in garnet, biotite, and chlorite composition in medium-grade pelitic rocks from the Dalradian, Scotland, with particular reference to the zonation in garnet”, Contribution to Mineralogy and Petrology, 18 (1968) 347-371.

[19] Taylor J., Setevens G., “Selective entrainment of peritectic garnet into S-Type granitic magmas: Evidance from Archean mid-crustal anatectites”, Lithos, 120 (2010) 277-292.

[20] Seprlich R., Giere R., Frey M., “Evolution of compositional polarity and zoning in tourmaline during prograde metamorphism of sedimentary rocks in the Swiss Central Alps.”, American Mineralogists, 81 (1996) 1222-1236.

[21] Henry D.J., Dutrow B.L., “Metamorphic tourmaline and its petrologic applications. In: Grew Es. Anovitz LM (eds) Boron. Mineralogy, Petrology and Geochemistry. The Mineralogical Society of America, Washington, Dc.”, Review Mineralogy 33 (1996) 503-557.

[22] Samson I.M., Sinclair W.D., “Magmatic hydrothermal fluids and the origin of quartz-tourmaline orbicules in the Seagull batholith, Yukon Territory”, Canadian Mineralogists, 30 (1992) 937-954.

[23] Truscott M.G., Shaw D.M., “Boron in chert and Precambrian siliceous iron formation”, Geochimca et Cosmochimca Acta, 48 (1984) 2220-2313.

[24] Torres–Ruiz J., Pesquera A., Gil–Crespo P.P., Velilla N., “Origin and petrogenetic implication of tourmaline–rich rocks in the Sierra Nevada (Betic Cordillera, Southeastern Spain)”, Chemical Geology, 197 (2003) 55-86.

[25] Wolf M.B., London D., “Boron in granitic magmas stability of tourmaline in equilibrium with biotite and cordierite”, Contribution to Mineralogy and Petrology, 130 (1997) 12-30.

[26] Gaweda A., Pieczka A., Kraczka J., “Tourmalines from the Western Tatra Mountains(W–Carpathians, S- Poland): Their characteristics and petrogenetic important”, Europian Journal of Mineralogy, 14 (2002) 943-955.

[27] طهماسبی ز، احمدی خلجی ا، رجاییه م، "تورمالین‌زایی در توده‌ی گرانیتوئیدی آستانه (جنوب غرب اراک)"، مجله بلورشناسی و کانی شناسی ایران، شماره 3 (1338) 369-380

[28] Yardley B.W.D., Rochelle C.A., Barnicoat A.C., Lioyd G.E., “Oscillatory zoning in metamorphic mineral: an indicator of infiltration metasomatism”, Mineralogical Magazine, 55 (1991) 357-365.

[29] Yuan C., Sun M., Xiao W., Wilde S., Li X., Liu X., Long X., Xia X., Ye K., Li J., “Garnet-bearing tonalitic porphyry from East Kunlun, Northeast Tibrtan Plateau: implications for adakite and magmas from the MASH Zone”, International Journal of Earth Sciences (Geol Rundsch), 98 (2009) 1489-1510.

[30] حسین میرزائی ز.، سپاهی ع.ا.، موذن م.، حسین میرزائی ز.، دادخواه ر.، "بررسی عوامل کنترل کننده‌ی ریخت شناسی بلورهای گارنت در سنگ‌های دگرگون و آذرین منطقه همدان"، مجله بلورشناسی و کانی‌شناسی ایران، شماره 4 (1389) 519-530.