استفاده از ترکیب شیمیایی کلینوپیروکسن در تحلیل شرایط فیزیکی صعود ماگما، بررسی موردی سنگهای آتشفشانی ائوسن در منطقه قهرود (شمال اصفهان)

زمین شناسی اقتصادی

مقاله 3، دوره 8، شماره 1 - شماره پیاپی 14، تیر 1395، صفحه 61-78   

نوع مقاله: علمی- پژوهشی

شناسه دیجیتال (DOI): 10.22067/econg.v8i1.38857

نویسندگان

محمد سیاری^* ؛ مرتضی شریفی

اصفهان

چکیده

در منطقه قهرود (شمال اصفهان)، سنگهای آتشفشانی با ترکیب آندزیت تا بازالت به‌صورت توده‌هایی با ابعاد مختلف پراکنده‌اند. از نظر کانی‌شناسی، سنگهای آتشفشانی بازالتی مورد بررسی از فنوکریست‌های پلاژیوکلاز به‌همراه بلورهای کوچکتر کلینوپیروکسن در زمینه‌ای از میکرولیت، شیشه و کانیهای کدر تشکیل شده‌اند. پلاژیوکلازها ترکیب لابرادوریت- بیتونیت (41-An85-58Ab15) دارند و کلینوپیروکسنها از نوع اوژیت (26-En41-49Di29-38Fs17) هستند. ترکیب کلینوپیروکسن‌ها نشان می‌دهد، ماگمای مادر سنگها دارای ماهیت تولئیتی است. بر اساس محاسبات نظام‌‌مند زمین‌دما- فشارسنجی با استفاده از نرم‌افزار تخصصی SCG، کلینوپیروکسنها در محدوده دمایی حدود 1120-1170 درجه سانتیگراد و محدوده فشار حدود 2-6 کیلوبار متبلور شده‌‌اند. پردازشهای آماری نشان می‌دهد، همگام با صعود ماگما و تبلور هم‌زمان پیروکسن‌‌ها، در قبال هر درجه سانتی‌گراد کاهش دما، به میزان 6/84 بار از فشار وارد بر ماگما کاسته شده که معادل با 320 متر کاهش عمق در پوسته قاره‌ای است.

کلیدواژه‌ها

کلینوپیروکسن؛ دما- فشارسنجی؛ سنگهای آتشفشانی؛ قهرود

مراجع

Aftabi, A. and Atapour, H., 2000. Regional aspects of shoshonitic volcanism in Iran. Episodes, 23(2): 119-125.

Agard, P., Omrani, J., Jolivet, L., Whitechurch, H., Vrielynck, B., Spakman, W., Monie, P., Meyer, B. and Wortel, R., 2011. Zagros orogeny: a subduction-dominated process. In: O. Lacombe, B. Grasemann and G. Simpson (Editors), Geodynamic Evolution of the Zagros. Geological Magazine, Cambridge, pp. 692-725.

Allen, M., Jackson, J. and Walker, R., 2004. Late Cenozoic reorganization of the Arabia-Eurasia collision and the comparison of short-term and long-term deformation rates. Tectonics, 23(2): 1-16.

Amidi, S.M., Emami, M.H. and Michel, R., 1984. Alkaline character of Eocene volcanism in the middle part of Central Iran and its geodynamic situation. Geologische Rundschau, 73(3): 917–932.

Barker D.S., 1983. Igneous rocks. Englewood cliffs, New jersey, 415 pp.

Berger, J., Femenias, O., Mercier, J.C.C. and Demaiffe, D., 2005. Ocean-floor hydrothermal metamorphism in the Limousin ophiolites (western French Massif Central): evidence of a rare preserved Variscan oceanic marker. Journal of Metamorphic Geology, 23(9): 795-812.

Best, M.G., 2003. Igneous and metamorphic petrology. Blackwell science ltd, Oxford UK, 729 pp.

Deer, W.A., Howie, R.A. and Zussman, J., 2013. An Introduction to the Rock Forming Minerals. Mineralogical Society, London, 498 pp.

Dewey, J.F., Hempton, M.R., Kidd, W.S.F., Saroglu, F. and Sengo, A.M.C., 1986. Shortening of continental lithosphere: The neotectonics of Eastern Anatolia - a young collision zone. In: M.P. Coward and A.C. Ries (Editors), Collision Zone Tectonics. Geological Society of London Special Publication, London, pp. 3-36.

Dilek, Y., Imamverdiyev, N. and Altunkaynak, S., 2010. Geochemistry and tectonics of Cenozoic volcanism in the Lesser Caucasus (Azerbaijan) and the peri-Arabian region: collision-induced mantle dynamics and its magmatic fingerprint. International Geology Review, 52(4-6): 536-578.

Dilek, Y. and Sandvol, E., 2009. Seismic Structure, Crustal Architecture and Tectonic Evolution of the Anatolian-African Plate Boundary and the Cenozoic Orogenic Belts in the Eastern Mediterranean Region. Geological Society of London Special Publication, 327: 127-160.

Dioh, E., Beziat, D., Gregoire, M. and Debat, P., 2009. Origin of rare earth element variations in clinopyroxene from plutonic and associated volcanic rocks from the Foulde basin, Northern Kedougou inlier, Senegal, West Africa. European Journal of Mineralogy, 21(5): 1029-1043.

Droop, G.T.R., 1987. A general equation for estimating Fe3+ concentrations in ferromagnesian silicates and oxides from microprobe analyses, using stoichiometric criteria. Mineralogical Magazine, 51(361): 431-435.

Emami, M.H., 1981. Geologie de la region de Qom-Aran (Iran), Contribution ả l׳ etude dynamique et geochimique du volcanisme tertiaire de l׳Iran central. Ph.D. these, Universite de Grenoble, France, 489 pp.

Ghadami, G., Moradian, A. and Mortazavi, M., 2008. Post-collisional Plio–Pleistocene adakitic volcanism in Central Iranian volcanic belt: geochemical and geodynamic implications. Journal of Sciences, Islamic Republic of Iran, 19(3): 223-235.

Hassanzadeh, J., 1993. Metallogenic and tectonomagmatic events in the SE sector of Cenozoic active continental margin of Central Iran (Sharebabak area), Kerman province. Ph.D. thesis, University of California, Los Angeles, USA, 204 pp.

Jackson, J. and McKenzie, D., 1984. Active tectonics of the Alpine-Himalayan belt between western Turkey and Pakistan. Geophysical Journal International, 77(1): 185-264.

Jahangiri, A., 2007. Post-collisional Miocene adakitic volcanism in NW Iran: geochemical and geodynamic implications. Journal of Asian Earth Sciences, 30(3-4): 433-447.

Khodami, M., 2009. Petrology of Plio-Quaternary volcanic rocks in south-east and north-west of Isfahan. PhD Thesis, University of Isfahan, Isfahan, Iran, 174 pp (in Persian with English abstract).

Kretz, R., 1983. Symbols for rock-forming minerals. American Mineralogist, 68(1-2): 277- 279.

Le Bas M.J., 1962. The role of aluminium in igneous clinopyroxenes with relation to their parentage. American Journal of Science, 260(4): 267-288.

Leterrier, J., Maury, R.C., Thonon, P., Girard, D. and Marchal, M., 1982. Clinopyroxene composition as method of identification of the magmatic affinities of paleo-volcanic series. Earth and Planetary Science Letters, 59(1): 139-154.

Lindsley, D.H., 1983. Pyroxene thermometry. American Mineralogist, 68(5-6): 477-493.

McClusky, S., Balassanian, S., Barka, A., Demir, C., Ergintav, S., Georgiev, G., Gurkan, O., Hamburger, M., Hurst, K., Kahle, H., Kastens, K., Kekelidze, G., King, R., Kotzev, V., Lenk, O., Mahmoud, S., Mishin, A., Ndariya, M., Ouzounis, A., Paradissis, D., Peter, Y., Prilepin, M., Reilinger, R., Sanli, I., Seeger, H., Tealeb, A., Toksoz, M.N. and Veis, G., 2000. Global Positioning System constraints on plate kinematics and dynamics in the eastern Mediterranean and Caucasus. Journal of Geophysical Research, 105(B3): 5695-5719.

McClusky, S., Reilinger, R., Mahmoud, S., Ben Sari, D. and Tealeb, A., 2003. GPS constraints on Africa (Nubia) and Arabia plate motions. Geophysical Journal International, 155(1): 126-138.

Mendenhall, W. and Sincich, T., 2011. A Second Course in Statistics: Regression Analysis. Pearson, USA, 816 pp.

Montgomery, D.C., Peck, E.A. and Vining, G.G., 2012. Introduction to Linear Regression Analysis. Wiley, New Jersey, 646 pp.

Morimoto, N. and Kitamura, M., 1983, Q-J diagram for classification of pyroxenes. Journal of the Japanese Association of Mineralogy. Petrology and Economic Geology, 78: 141.

Morimoto, N., 1989. Nomenclature of pyroxenes. Canadian Mineralogist, 27(1): 143-156.

Nakamura, D., 2009. A new formulation of garnet-clinopyroxene geothermometer based on accumulation and statistical analysis of a large experimental data set. Journal of Metamorphic Geology, 27(7): 495-508.

Nimis, P.A., 1995. A clinopyroxene geobarometer for basaltic systems based on crystal-structure modeling. Contributions to Mineralogy and Petrology, 121(2): 115-125.

Nimis, P. and Taylor, W.R., 2000. Single clinopyroxene thermobarometry for garnet peridotite. Part 1. Calibration and testing of a Cr-in-Cpx barometer and an enstatite-in-Cpx thermometer. Contributions to Mineralogy and Petrology, 139(5): 541-554.

Nimis, P. and Ulmer, P., 1998. Clinopyroxene geobarometry of magmatic rocks. 1. An expanded structural geobarometer for anhydrous and hydrous, basic and ultrabasic systems. Contributions to Mineralogy and Petrology, 133(1-2): 122-135.

Omrani, J., Agard, P., Witechurch, H., Benoit, M., Prouteau, G. and Jolivet, L., 2008. Arc magmatism and subduction history beneath the Zagros Mountains, Iran: a new report of adakites and geodynamic consequences. Lithos, 106(3-4): 380-398.

Ottonello, G., 1997. Principles of geochemistry. Columbia Universiyt Press, New York, 894 pp.

Putirka, K., 2008. Thermometers and Barometers for Volcanic Systems. Reviews in Mineralogy and Geochemistry, 69(1): 61-120.

Putirka, K., Johnson, M., Kinzler, R. and Walker, D., 1996. Thermobarometry of mafic igneous rocks based on clinopyroxene-liquid equilibria, 0-30 kbar. Contributions to Mineralogy and Petrology, 123(1): 92-108.

Putirka, K., Mikaelian, H., Ryerson, F. and Shaw, H., 2003. New clinopyroxene-liquid thermobarometers for mafic, evolved, and volatile-bearing lava compositions, with applications to lavas from Tibet and the Snake River Plain, Idaho. American Mineralogist, 88(10): 1542-1554.

Sayari, M., 2012. APG: An efficient software program for Amp-Pl thermobarometry based on graphical method. Journal of Sciences, Islamic Republic of Iran, 22(4): 345-349.

Sayari, M., 2015. Petrogenesis and evolution of Oligocene-Pliocene volcanism in the central part of Urumieh-Dokhtar Magmatic Arc (NE of Isfahan). Ph.D Thesis, University of Isfahan, Isfahan, Iran, 195 pp (in Persian with English abstract).

Sayari, M. and Sharifi, M., 2014. SCG: A computer application for single clinopyroxene geothermobarometry. Italian Journal of Geosciences 133(2): 315-322.

Sayari, M., Sharifi, M. and Ahmadian, J., 2014a. Determining magmatic series and oxygen fugacity of volcanic rocks in the east of Kamu (North of Esfahan) based on biotite chemistry. Journal of Economic Geology, 6(1): 149-161 (in Persian with English abstract).

Sayari, M., Sharifi, M. and Tabatabaei Manesh, S.M., 2014b. Thermo-barometry of amphibole-plagioclase phenocrysts in volcanic rocks in the east of Kamu, north of Isfahan province (middle part of the Central Iranian volcanic belt). Petrology, 18(5): 93-104 (in Persian with English abstract).

Spear, F.S., 1995. Metamorphic phase equilibria and pressure-temperature-time paths. Mineralogical Society of America, Washington D.C., 799 pp.

Vieten, K. and Hamm, H.M., 1978. Additional notes on the calculation of the crystal chemical formula of clinopyroxenes and their contents of Fe3+ from microprobe analyses. Neues Jahrbuch für Mineralogie Monatshefte, 2: 71-83.

Zahedi, M., Amidi, S.M. and Zohrehbakhsh, A.M., 1981. Geological map of Kashan, scale 1:250,000. Geological Survey of Iran.