نوع مقاله : مقاله پژوهشی
نویسندگان
1 کارشناسی ارشد، دانشکده زمین‌شناسی، پردیس علوم، دانشگاه تهران، تهران، ایران
2 دانشکده زمین شناسی، پردیس علوم، دانشگاه تهران، تهران، ایران
3 دانشیار، دانشکده زمین‌شناسی، پردیس علوم، دانشگاه تهران، تهران، ایران
چکیده
توده نفوذی ده‌بالا در محدوده 45 کیلومتری جنوب باختر شهرستان بویین‌زهرا در استان قزوین رخنمون دارد. این توده دارای انکلاوهای میکروگرانولار مافیک بسیار با اشکال گرد شده و بیضوی و با اندازه های 2 تا بیشینه 30 سانتی متر است. انکلاوها از مونزودیوریت، دیوریت و گابرودیوریت و سنگ های میزبان بیشتر از گرانودیوریت تشکیل شده اند. حضور بافت های عدم تعادل همچون درشت بلورهای پلاژیوکلاز با سطوح تحلیلی و بافت غربالی، کوارتز اوسلی و آپاتیت های سوزنی در انکلاوها می تواند نشانگر رخداد آمیختگی ماگمایی در توده نفوذی ده‌بالا باشد. توزیع عناصر اصلی و فرعی و خاکی کمیاب به روشنی تبادل میان ماگماهای فلسیک میزبان و انکلاوها را در طی آمیختگی ماگمایی بازتاب می دهد. غنی‌شدگی غیر عادی REE در انکلاوها نسبت به سنگ فلسیک میزبان، نشانه ماهیت متفاوت دو ماگمای فلسیک و مافیک به وجود آورنده این دو سنگ و ناهمگنی شکلی ایجاد شده در انکلاوها (ابعاد فرکتال) ناشی از فرایندهای آمیختگی ماگمایی است. ابعاد فرکتال انکلاوها میان 14/1 تا 29/1متغیر است. رده 29/1 بالاترین فراوانی را در نمودار ستونی نشان می دهد. بر پایه بعد فرکتال (Dbox) انکلاوها، نسبت لگاریتم گرانروی گرانودیوریت میزبان به انکلاو، طیفی از 56/0 تا 96/0 را نشان می دهد و مد آن در نمودار ستونی 96/0 است. بیشتر انکلاوها در توده نفوذی ده‌بالا با محتوای سیلیس نزدیک به 56 درصد و مقادیر بالای ابعاد فرکتال مشخص می شوند. این مسئله آمیختگی کم ماگمای مافیک انکلاوها با ماگمای فلسیک میزبان را تأیید می‌کند و نشانه افزایش اختلاف گرانروی میان ماگماهای گرانودیوریت میزبان و انکلاوهاست.
کلیدواژه‌ها
موضوعات
آقانباتی، ع.، 1383- زمین‌شناسی ایران، انتشارات سازمان زمین‌شناسی و اکتشافات معدنی کشور، 620ص.
اقلیمی، ب.، 1378- نقشه زمین‌شناسی 100000/1دانسفهان (خیارج)، انتشارات سازمان زمین‌شناسی و اکتشافات معدنی کشور.
صفرزاده، ا.، 1386- پتروگرافی و پترولوژی توده نفوذی حاجی‌آباد، پایان‌نامه کارشناسی ارشد، دانشگاه شهید بهشتی، تهران.
طباخ شعبانی، ا. ا.، 1369- پتروگرافی و پترولوژی تودههای نفوذی جنوب بویین زهرا، پایان‌نامه کارشناسی ارشد، دانشگاه خوارزمی، کرج.
نوگل‌سادات، ا. ا.، هوشمندزاده، ا.، 1984- نقشه زمین‌شناسی 250000/1 ساوه، انتشارات سازمان زمین‌شناسی و اکتشافات معدنی کشور.
Agard, P., Omrani, J., Jolivet, L., Whitechurch, H., Vrielynck, B., Spak-man, W., Monié, P., Meyer, B. and Wortel, R., 2011- Zagros orogeny: a subduction-dominated process. Geological Magazine, 148: 692–725.
Alberta, H., Perugini, D. and Marti, J., 2014- Fractal Analysis of Enclaves as a New Tool for Estimating Rheological Properties of Magmas During Mixing: The Case of Montan a Reventada (Tenerife, Canary Islands). Pure and Applied Geophysics DOI 10.1007/s00024-014-0917-5.
Baker, D. R., 1990- Chemical inter-diffusion of dacite and rhyolite: anhydrous measurements at 1 atm and 10 kbar, application of transition state theory, and diffusion in zoned magma chambers. Contributions to Mineralogy and Petrology 104: 407–423.
Barbarin, B. and Didier, J., 1992- Genesis and evolution of mafic microgranular enclaves through various types of interaction between coexisting felsic and mafic magmas. Transactions of the Royal Society of Edinburgh Earth Sciences, 83: 145–153.
Barbarin, B., 1991- Enclaves of the Mesozoic calc-alkaline granitoids of the Sierra Nevada batholith, California. In: Didier J. and Barbarin B. (Eds.), Enclaves and Granite Petrology, Developments in Petrology, Elsevier, Amsterdam, 13: 135–154.
Barbarin, B., 2005- Mafic magmatic enclaves and mafic rocks associated with some granitoids of the central Sierra Nevada batholith, California: nature, origin, and relations with the hosts. Lithos, 80: 155–177.
Baxter, S. and Feely, M., 2002- Magma mixing and mingling textures in granitoids: examples from the Galway Granite, Connemara, Ireland. Mineralogy and petrology, 76: 63-74.
Berberian, M. and King, G. C. P., 1981- Towards a palaeogeography and tectonic evolution of Iran. Canadian Journal of Earth Sciences, 18: 210-265.
Best, M., 1982- Igneous and Metamorphic Petrology. Freeman, San Francisco, 630pp.
Bindeman, I. N. and Davis, A. M., 1999- Convection and redistribution of alkalis and trace elements during the mingling of basaltic and rhyolite melts. Petrology, 7 (1): 99–110.
Boynton, W. V., 1984- Geochemistry of the rare earth elements: Meteorite studies. In: RareEarth element geochemistry (Ed. Henderson, P.), Elsevier, Amsterdam, 63-114.
De Campos, C. P., Perugini, D., Ertel-Ingrisch, W., Dingwell, D. B. and Poli, G., 2011- Enhancement of magma mixing efficiently by chaotic dynamics: an experimental study. Contribution to Mineralogy and Petrology, 161: 863–881.
De La Roche, H., Leterrier, J., Grande Claude, P. and Marchal, M., 1980- A classification of volcanic and plutonic rocks using R1-R2 diagrams and major element analyses – its relationship and current nomenclature. Chemical Geology, 29: 183-210.
Debon, F., 1991- Comparative major element chemistry in various ‘‘microgranular enclave–plutonic host’’ pairs. In: Didier J. Barbarin B. (Eds.), Enclaves and Granite Petrology. Developments in Petrology, Elsevier, Amsterdam, 13: 293–312.
Didier, J. and Barbarin, B., 1991- Enclaves and Granite Petrology, Developments in Petrology, Elsevier, Amsterdam, 13: 625 pp.
Falcon, N. L., 1974- Outline of Geology of Iranian Makran. Geography Journal, 140: 284-291.
Farner, M. J., Lee, C. T. A. and Putirka, K. D., 2014- Mafic-felsic magma mixing limited by reactive processes: A case study of biotite-rich rinds on mafic enclaves. Earth planet science letter, 393: 49-50.
Fernandez, A. N. and Barbarin, B., 1991- Relative rheology of coeval mafic and felsic magmas: nature of resulting interaction processes. Shape and mineral fabrics of microangular enclaves. In: Didier J. Barbarin B. (Eds.), Enclaves and Granite Petrology, Developments in Petrology, Elsevier, Amsterdam, 13: 19–23.
Gamble, J. A., 1979- Some relationships between coexisting granitic and basaltic magmas and the genesis of hybrid rocks in the Tertiary Central Complex of Slieve Gullion, Northeast Ireland. Journal of Volcanology and Geothermal Research, 5: 297-316.
Grogan, S. E. and Reavy, R. J., 2002- Disequilibrium textures in the Leinster Granite Complex, SE Ireland: evidence for acid-acid magma mixing. Mineralogical Magazine, 66 (6): 929–939.
Johnston, A. D. and Wyllie, P. J., 1988- Interaction of granitic and basic magmas: experimental observations on contamination processes at l0 Kbar with H2O. Contributions to Mineralogy and Petrology, 98: 352-362.
Kocak, K., Zedef, V. and Kansun, G., 2011- Magma mixing/mingling in the Eocene Horoz (Nigde) granitoids, Central southern Turkey: evidence from mafic microgranular enclaves. Mineralogy and petrolgy, 103(1-4): 149-176.
Kouchi, A. and Sunagawa, I., 1985- A model for mixing basaltic and dacitic magmas as deduced from experimental data. Contributions to Mineralogy and Petrology, 89: 17-23.
Kretz, R., 1983- Symbols for rock-forming minerals. American Mineralogist, 68: 277-279.
Kumar, S. and Pieru, T., 2010- Petrography and major element geochemistry of microgranular enclaves and Neoproterozoic granitoids of South Khasi, Meghalaya: evidence of magma mixing and alkali diffusion. Journal of Geological Society India, 76: 345–360.
Kumar, S., 2010- Mafic to hybrid microgranular enclaves in the Ladakh batholith, northwestern Himalaya: implications on calc-alkaline magma chamber processes. Journal of Geological Society of India, 76: 5–25.
Kumar, S., Rino, V. and Pal, A. B., 2004- Field evidence of magma mixing from microgranular enclaves hosted in Palaeoproterozoic Malanjkhand granitoids, central India. Gondwana Research, 7: 539–548.
Lesher, C. E., 1990- Decoupling of Chemical and Isotopic Exchange during Magma Mixing. Nature, 344: 235-237.
Mandelbrot, B. B., 1982- The Fractal Geometry of Nature. W. H. Freeman, New York.
Mandelbrot, B., 1989- Fractal geometry: What is it, and what does it do? in: F. R. S. Fleischmann, D. Tildesley, R. C. Ball (Eds.), Fractals in the Natural Sciences, Princeton University Press, Princeton NJ.
Ottino, J. M., Leong, C. W., Rising, H. and Swanson, P. D., 1988- Morphological structures produced by mixing in chaotic flows. Nature, 333: 419-425.
Perugini, D. and Poli, G., 2012- The mixing of magmas in plutonic and volcanic environments: analogies and differences. Lithos, 153: 263–279.
Perugini, D. and Poli, G., 2002- Chemical Diffusion in Complex Geometries during Chaotic Mixing of Magmas. Eurogranites (abstract), 46pp.
Perugini, D. and Poli, G., 2004- Determination of the degree of compositional disorder in magmatic enclaves using SEM, X-ray element, maps. European Journal of Mineralogy, 16: 431–442.
Perugini, D. and Poli, G., 2005- Viscous fingering during replenishment of felsic magma chambers by continuous inputs of mafic magmas: field evidence and fluid-mechanics experiments. Geology, 33 (1): 5–8.
Perugini, D., De Campos, C. P., Dingwell, D. B., Petrelli, M. and Poli, G., 2008- Trace element mobility during magma mixing: preliminary experimental results. Chemical Geology, 256: 146–157.
Perugini, D., Poli, G. and Mazzuoli, R., 2003- Chaotic advection, fractals and diffusion during mixing of magmas: evidence from lava flows. Journal of Volcanology and Geothermal Reasearch, 124: 255-279.
Perugini, D., Poli, G., Christofides, G., Soldatos, T., Koroneos, A. G. and Eleftheriadis, G., 1999- Importance of magmatic interaction processes in the evolution of tertiary granitoids of Serbomacedonian and Rhodope Massifs (Northern Greece), EUG10 Journal of Conference Abstracts, 4 (1): 670.
Rollinson, H., 1993- Using Geochemical Data: Evaluation, Presentation, Interpretation. John Wiley and Sons, New York 5.
Rudnick, R. L. and Gao, S., 2003- Composition of the continental crust. In: Holland H.D. Turekian K.K. (Eds.), Treatise on Geochemistry. Elsevier, Oxford, 3:1–64 pp.
Sawka, W. N., 1988- REE and trace element variations in accessory minerals and hornblende from the strongly zoned McMurry Meadows pluton, California. Transactions of the Royal Society of Edinburgh, 79: 157-168.
Słaby, E., Smigielski, M., Smigielski, T., Domonik, A., Simon, K. and Kronz, A., 2011- Chaotic three-dimensional distribution of Ba, Rb, and Sr in feldspar megacrysts grown in an open magmatic system. Contribution to Mineralogy and Petrology, 162: 909–927.
Sun, S. S. and McDonough, W. F., 1989- Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. Geological Society, London, Special Publications, 42: 313-345.
Tate, M. C., Clarke, D. and Heaman, L. M., 1997- Progressivehybridization between Late Devonian mafic-intermediate and felsic magmas in the Megume zone of Nova Scotia,Canada. Contributions to Mineralogy and Petrology, 126: 401–415.
Tindle, A. G., 1991- Trace element behaviour in microgranular enclaves from granitic rocks. In: Didier J. Barbarin B. (Eds.), Enclaves and Granite Petrology, Developments in Petrology, Elsevier, Amsterdam, 13: 13–331.
Vernon, R. H., 1983- Restites, xenoliths and microgranitoid enclaves in granites. Journal and proceedings of the Royal Society of New South Wales (London), 116: 77-103.
Vernon, R. H., 1984- Microgranitoid enclaves in granites: globules of hybrid magma quenched in a plutonic environment. Nature, 309 (5967): 438–439.
Vernon, R. H., Etheridge, M. A. and Wall, V. J., 1988- Shape and microstructures of microgranitoid enclaves: indicators of magma mingling and flow. Lithos, 22: 1–11.
Vogel, T. A., Younker, L. W., Wilband, J. T. and Kampueller, E., 1984- Magma mixing: the Marsco suite, Isle of Skye, Scotland. Contributions to Mineralogy and Petrology, 87: 231- 241.
Wang, H. Z., Chen, P. R., Sun, L. Q., Ling, H. F., Zhao, Y. D. and Lan, H. F., 2015- Magma mixing and crust–mantle interaction in Southeast China during the Early Cretaceous: Evidence from the Furongshan granite porphyry and mafic microgranular enclaves. Journal of Asian Earth Sciences, 111: 72-78.
Watson, E. B., 1981- Diffusion in magmas at depth in the earth: the effects of pressure and dissolved He2O. Earth Planetary Science Letter, 52: 291-301.
Wiebe, R. A., 1973- Relation between coexisting basaltic and granitic magmas in a composite dike. American JournalofScience, 273: 130-151.
Wiebe, R. A., Smith, D., Sturn, M., King, E. M. and Seckler, 1997- Enclaves in the Cadillac Mountain granite (Coastal Maine): samples of hybrid magma from the base of the chamber. Journal of Petrology, 38: 393–426.
Xiong, F. H., Ma, C. Q., Zhang, J. Y. and Liu, B., 2011- The origin of mafic microgranular enclaves and their host granodiorites from East Kunlun, Northern Qinghai–Tibet Plateau: implications for magma mixing during subduction of Paleo-Tethyan Lithosphere. Mineralogy and Petrology, 104: 211–224.
Yang, J. H., Wu, F. Y., Wilde, S., Xie, L. W., Yang, Y. H. and Liu, X. M., 2007- Tracing magma mixing in granite genesis: in situ U–Pb dating and Hf-isotope analysis of zircons. Contributions to Mineralogy and Petrology, 153: 177–190.
Zhao, K. D., Jiang, S. Y., Yang, S. Y., Dai, B. Z. and Lu, J. J., 2012- Mineral chemistry, trace elements and SrNdHf isotope geochemistry and petrogenesis of Cailing and Furong granites and mafic enclaves from the Qitianling batholith in the Shi-Hang zone, South China. Gondwana Research, 22: 310–324.
)