تغییرات پاراژنزهای کانی‌شناسی گرانولیت‌های شمال غرب سبزوار در طی تحولات دگرگونی

نصرآبادی, محسن; معین‌وزیری, حسین; رضوی, محمد حسین; محجل, محمد

تغییرات پاراژنزهای کانی‌شناسی گرانولیت‌های شمال غرب سبزوار در طی تحولات دگرگونی

نویسندگان

¹ دانشگاه بین المللی امام خمینی قزوین

² دانشگاه تربیت معلم

³ دانشگاه تربیت مدرس

چکیده

بیرونزدگیهایی از متابازیتها در داخل نوار افیولیتی شمالغرب سبزوار دیده میشوند که در شرایط رخسارهی گرانولیت فشار بالا دگرگون شدهاند. بر مبنای پاراژنزهای کانیشناسی، ساختارهای واکنشی بین مجموعههای کانیشناسی مختلف، روابط کانیشناسی و بافتی بین ادخال و پورفیربلاست و قلمرو پایداری مجموعههای کانیشناسی متفاوت یک دگرگونی پنج مرحلهای (M1 تا M5) تشخیص داده شد که عبارتند از: مرحلهی دگرگونی پیشرونده (M1)، مرحلهی اوج دگرگونی (M2)، کلیفیتیزاسیون گارنت و تشکیل سیمپلکتیت آمفیبول+ پلاژیوکلاز بهصورت کرونا (M3)، جانشینی بخشی یا کامل گارنت بهوسیله مجموعهی آمفیبول+ کلریت+ اپیدوت(M4) و تشکیل رگههای پرهنیت و زئولیت در شکستگیهای سنگها (M5). دادههای دما- فشارسنجی این مراحل یک مسیر فشار- دمای دگرگونی ساعتگرد نشان میدهد که از نظر زمینساختی با برخورد خرده قارهی ایران مرکزی با بلوک البرز و سپس فرسایش و بالاآمدگی بعدی سازگار است.

کلیدواژه‌ها

عنوان مقاله [English]

Mineralogical paragenesis variations of northwest Sabzevar granulites during metamorphic evolutions

چکیده [English]

There are metabasite exposures inside ophiolitic belt of northwest Sabzevar that metamorphosed under high pressure granulite facies. On the basis of mineralogical paragenesis, reactional textures between different mineralogical assemblages, textural and mineralogical relations between inclusion and porphyroblast and stability fields of different mineralogical assemblages, five stages of evolution of metamorphism is distinguished. These stages consist of prograde metamorphic stage (M1), peak metamorphic stage (M2), garnet kelyphitisation as the formation of Pl+Am symplectite and corona (M3), partial or quite replacement of garnet by Am+Chl+Ep assemblage (M4) and the occurrence of Prh-Zl veins. The thermobarometric data of these stages represent a clock-wise P-T path. This path is consistent with the collision of the Iranian micro-continent with the Alborz block and later erosion and uplifting.

کلیدواژه‌ها [English]

Sabzevar
granulite
mineralogical paragenesis
metamorphic evolution

مراجع

[1] Smulikowski W., Desmons J., Hart B., Sassi F. P., Schmid R., "Towards a unified nomenclature of metamorphism: 3 Types, Grades and Facies. International :union: of Geological Sciences-Subcommission of the Systematic of Metamorphic Rocks (SCMR)", (1997) Work in progress.

[2] Green D.H., Ringwood A.E., "An experimental investigation of the gabbro to eclogite transition and petrological implications", Geochimica et Cosmochimica Acta 31(1967), 767–833.

[3] Lensch G., Mihm A., Alavi Tehrani N., "Major element geochemistry of the ophiolites north of Sabzevar (Iran)", J. P. Geol. Planet. Mh . 7)1979) 415-447.

[4] Leake B.E., Alan R.W., William D.B., Ernst A.J.B., Giovanni F., Jeol D.J., Frank C.H., Hanan J.K., Vladimir G.K., John C.S., Nicholas C.N.S., Eric J.W.W., "Nomenclature of amphiboles: Additions and revisions to the International Mineralogical Associations amphibole nomenclature", American Mineralogist 89(2004) 883–887.

[5] Carswell D.A., "Eclogites and eclogite facies: definitions and classification", In: Eclogite Facies Rocks, (ed. D. A. Carswell), (1990) 219-221. Blackie, London.

[6] O’Brien P.J., "Garnet zoning and reaction textures in overprinted eclogites, Bohemian Massif, European Variscides: a record of their thermal history during exhumation", Lithos 41(1997) 119-133.

[7] O’Brien P.J., RÖtzler J., "High-pressure granulites: Formation, Recovery of Peak Conditions and Implication for Tectonics", Journal of Metamorphic Geology 21 (2003) 3-20.

[8] Holland T.J.B., Powell R., "An internally consistent thermodynamic data set for phases of petrological interest", Journal of Metamorphic Petrology 16(1998) 309-343.

[9] Ellis D.J., Green D.H., "An experimental study of the effect of Ca upon garnet-clinopyroxene Fe-Mg exchange equlibria", Contribution to Mineralogy and Petrology 71(1979) 13-22.

[10] Krogh Ravna E., "The garnet-clinopyroxene Fe -Mg geothermometer: an update calibration", Journal of Metamorphic Geology 18(2000a) 211-219.

[11] Krogh Ravna E., "Distribution of Fe and Mg between coexisting garnet and hornblende in synthetic and natural systems: an empirical calibration of the garnet – hornblende Fe-Mg geothermometer", Lithos 53(2000b) 305-321.

[12] Zack T., Moraes R., Kronz A., "Temperature dependence of Zr in rutile : empirical calibration of a rutile thermometer", Contribution to Mineralogy and Petrology 148(2004a) 471-488.

[13] Watson E.B., Wark D.A., Thomas J.B., "Crystalysation thermometers for zircon and rutile", Contribution to Mineralogy and Petrology 151(2006) 413-433.

[14] Ferry J., Watson E.B., "New thermodynamic models and revised calibrations for the Ti-in-zircon and Zr-in-rutile thermometers", Contribution to Mineralogy and Petrology 154(2007) 429-437.

[15] Tomkins A.G., Pattison D.R.M., Frost B.R., "On the initiation of metamorphic sulfid anatexis", Journal of Petrology 48(2007) 511-535.

[16] Perkins D. III, Newton R.C., "Chamockite geobarometers based on coexisting gamet-plroxene-plagioclase-quartz", Nature 292(1981) 144-146.

[17] Eckert J.O., Newton R.C., Kleppa O.G., "The ΔH of reaction and recalibration of garnet-pyroxene-plagioclase-quartze geobarometers in the CMAS system by solution calorimetry", American Mineralogist 76(1991) 148-160.

[18] Kohn M.J., Spear F.S., "Two new geobarometers for garnet amphibolites, with applications to Southeastern Vermont", American Mineralogist 75(1990) 89-96.

[19] McCarthy T.C., Patiño Douce A.E., "Empirical calibration of the silica-Ca-tschermak’s-anorthite (SCAn) geobarometer", Journal of Metamorphic Geology 16(1998) 675-689.

[20] Ernest W.G., Liu J., "Experimental phase-equilibrium study of Al- and Ti-contents of calcic amphibole in MORB-A semiquantitative thermobarometer", American Mineralogist 83(1998) 952-969.

[21] Vielzeuf D., Schmidt M.W., "Melting reactions in hydrous systems revisited: applications to metapelites, metagreywackes and metabasalts", Contributions to Mineralogy and Petrology 141(2001) 251-267.

[22] Holdaway M.J., "Significance of chloritoid-bearing rocks in the Picuris Range, New Mexico", Geological Society of America Bulletin 89(1978) 1404–1414.

[23] Liou J.G., Zhang R., Ernst W.G., Liu J., McLimans R., "Mineral parageneses in the Piampaludo eclogitic body, Gruppo di Voltri, western Ligurian Alps",(1998) Schweizerische

[24] Liu J., Bohlen S.R., Ernest W.G., "Stability of hydrous phases in subducting oceanic crust", Earth and Planetary Science Letters 143(1996) 161-171.

[25] Holland T.J.B., "The experimental determination of activities in disordered and short-range ordered jadeitic pyroxenes", Contributions to Mineralogy and Petrology 82(1983) 214–220.

[26] Harly S.L., "The origin of granulites: A metamorphic perspective", Geological Magazine 126(1989) 215-247.

[27] Sonder L.J., England P.C., Wernicke B.P., Christiansen R.L., "A physical model for Cenozoic extension of western North America In: Continental Extensional Tectonics", Special Publication 28(1987), (Eds Coward, M. P. Dewey, J. F. & Hancock P. L.), PP. 187-201. Geological Society, London.

[28] Wells P.R.A., "Thermal models for the magmatic accretion and subsequent metamorphism of continental crust", Earth and Planetary Science Letters 46(1980) 253-265.

[29] Bohlen S.R., 1987. "Pressure-temp erature-time path and a tectonic model for the evolution of granulites", Journal of Geology 95(1980) 617-632.

[30] Bohlen S.R., "On the formation of granulites", Journal of Metamorphic Geology 9(1991) 223-229.

[31] Hill R.I., Campbell I.R., Davis G.F., Griffiths R.W., "Mantle plumes and continental tectonics", Science 256(1992) 186-193.

[32] Sandiford M., Powell R., "Deep crustal metamorphism during continental extension: ancient and modern examples", Earth and Planetary Science Letters 79(1986) 151-158.

[33] Peacock S.M., "Creation and preservation of subduction-related inverted metamorphic gradients", Journal of Geophysical Research, B, Solid Earth and Planets 92(1987) 12763-12781.

[34] Cloos M., "Thermal evolution of convergent plate margin: thermal modeling and reevaluation of isotopic Ar-ages for blue schist in Franciscan subduction complex of California", Tectonics 4(1985) 421-433.

[35] StÖcklin J., "Possible ancient continental margins in Iran". In: Burke, C.A., Darke C. L. (Eds.), The geology of continent margins, Springer, New York, (1974) pp. 873-887.

[36] Stampfli G.M., "Etude geologique generale the I’ Elbourz oriental au sud de Gondbad-e-Qabus, Iran NE", These Geneve, (1978) 329 P.

[37] Berberian M., King G.C.P., "Toward a paleogeograpy and tectonic evolution of Iran", Can. J. Earth Science 18(1981) 210- 265.

[38] Baroze J., Macaudiere J., Montigny R., Noghreyan M., Ohnensteter M., Rocci G.A., "Ophiolites and related formations in the central part of the Sabzevar (Iran) and possible geotectonics reconstructions", Geodynamic Project (Geotraverse) in Iran: GSI, Rep. No.: 51(1983).