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Mineral chemistry and P-T estimations of Grt-Cpx amphibolites, SE Qarehaghaj-East Azerbaijan province

Document Type : Original Research Paper

Authors

1 Assistant Professor, Department of Geology, Islamic Azad University, Ahar Branch, Ahar, Iran

2 Associated Professor, Department of Earth Sciences, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran

3 Professor, Department of Earth Sciences, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran

Abstract

The study area is located in the Central Iran Zone, in the view of tectonic subdivisions of Iranian terrains. The main outcropping rock types are metabasites and amphibolites having Precambrian age. The amphibolites have been classified as Ep-amphibolite, normal amphibolite, Grt-amphibolite and Grt-Cpx amphibolite, considering characteristic mineral assemblages. The main textures are granoblastic and porphyrogranobastic. Mineral chemistry of Grt-Cpx amphibolites have been investigated in this contribution. The results have been used to estimate metamorphic P-T conditions. The compositions of amphiboles are pargasite and hornblende. Clinopyroxne is diopside. Plagioclases are rich in An content (An73.50-95.90) and Ab content is low (Ab3.90-24.70). Garnet have compositions as Alm (%45.90-%59.10)، Prp (%5.6-%16.1)، Sps (%10.90-%23.50)، GAU (%13.20-%23.70) . Garnet composition is non-uniform as increasing of Fe and Mg contents where Mn and Ca contents are decreased from the core to the rim. The peak metamorphic T-P obtained as 670 oC to 705 oC  at 8.5 Kbar respectively. The estimated pressure is consistent with the depth of ~25Km correspending to the lower crustal condition. The recorded mid P-T conditions of Grt-Cpx ampgibolites belonge to Barrovian type regional metamorphism. On the basis of geological and petrological studies from the SE Qarehaghaj and the analogies with comparable rocks from adjucent Precambrian terrains, it seems that the Pan-African Orogeny is the phase causing metamorphism and consolidation of the basement rocks. The Precambrian metabasites and amphibolites have been probably formed in this regard. The subsequent mid P-T metamorphism of the metabasites under upper amphibolite facies (Barrovian type metamorphism) have been most likely recorded related to continental collision between the Arabian plate and the Central Iranian micocontinent correspending to the Alpian Orogeny during Cenozoic.

Keywords

References
Abd El-Naby, H., Frisch, W. and Hegner, E., 2000- Evolution of Pan-African Wadi Haimur metamorphic sole, Eastern Desert, Egypt. Journal of Metamorphic Petrology, 18: 639-651.
Alavi, M., 1994- Tectonics of the Zagros orogenic belt of Iran: New data and interpretations. Tectonophysics, 229: 211–238.
Alavi, M., 2004- Regional stratigraphy of the Zagros Fold-Thrust belt of Iran and its proforelenad evolution. American Journal of Science, 304: 1–20.
Alavi, M., Hajian, J., Amidi, M. and Bolourchi, H., 1982- Geology of Takab-Shahin-Dez Quadrangle. The Ministry of Mines and Metals of Iran, Tehran, 100 p.
Anderson, J. L., 1983- Proterozoic anorogenic granite plutonism of North American. Geological Society of America Memoir, 161: 133-152.
Andreev, A. A., Rytsk, E. Y., Velikoslavinskii, S. D., Kotov, A. B., Yarmolyuk, V. V., Kovach, V. P. and Tolmacheva, E. V., 2015- Geodynamic settings of the formation of amphibolites of the Kichera zone of the Baikal-Muya foldbelt: Results of geochemical studies. Doklady Earth Sciences, 460 (2): 168-173.
Berberian, M. and King, G. C. P., 1981- Towards a paleogeography and tectonic evolution of Iran. Canadian Journal of Earth Sciences, 18: 210–265.
Colombi, A., 1988- Métamorphisme et géochemie des roches mafiques des Alpes ouest-centrales (géoprofil Viège–Domodossola–Locarno). Ph.D. thesis, University of Lausanne, 216 p.
Dahl, P. S., 1980- The thermal-compositional dependence of Fe2+-Mg distributions between coexisting garnet and pyroxene: applications to geothermometry. American Mineralogist, 65: 854-866.
Deer, W. A., Howie, R. A and Zussman, J., 1963- Rock-forming minerals,vol. 2, Longmans, Green, London.
Deer, W. A., Howie, R. A. and Zussman, J., 1978- Rock-forming minerals, 2A, single-chain silicates (2nd edition). Longman, U.K. and Wiley, New York.
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: 431–435.
Ellis, D. J. and Green, E. H., 1979- An experimental study of the effect of Ca upon garnet-clinopyroxene Fe-Mg exchange equilibria. Contribution to Mineralogy and Petrology, 71: 13-22.
Hajialioghli, R., Moazzen, M., Droop, G. T. R., Oberhansli, R., Bousquet, R., Jahangiri, A. and Ziemann, M., 2007- Serpentine polymorphs and P-T evolution of meta-peridotites and serpentinites in the Takab area, NW Iran. Minralogical Magazine, 71: 155–174.
Hammarstrom, J. M. and Zen, E., 1986- Aluminum in hornblende: An empirical igneous Geobarometer. American Mineralogist, 71: 1297-1313.
Kretz, R., 1983- Symbols for rock-forming minerals. American Mineralogist, 68: 277-279.
Leake, B. E., Woolley, A. R., Birch, W. D., Burke, E. A. J., Ferraris, G., Grice, J. D., Hawthorne, F. C., Kisch, H. J., Krivovichev, V. G., Schumacher, J. C., Stephenson, N. C. N. and Whittaker, E. J. W., 2004- Nomenclature of amphiboles: additions and revisions to the International Mineralogical Association’s amphibole nomenclature. Canadian Mineraogist,41: 1355-1370.
McCarthy, T. C. and Patiño Douce, A. E., 1998- Empirical calibration of the silica-Ca-tschermak’s anorthite (SCAn) geobarometer. Journal of Metamorphic Geology, 16: 675-686.
Moazzen, M., Hajialioghli, R., Möller, A., Droop, G. T. R., Oberhänsli, R., Altenberger, U. and Jahangiri A., 2013- Oligocene partial melting in the Takab metamorphic complex, NW Iran: Evidence from in situ U-Pb geochronology. Journal of Sciences, Islamic Republic of Iran, 24(3): 217-228.
Morimoto, N. and Kitamura, M., 1983- Q-J diagram for classification of pyroxenes. Journal of the Japanese - Association of Mineralogists, Petrologists and Economic Geologists, 78, 141 (in Japanese).
Morimoto, N., Fabries, J., Ferguson, A. K., Ginzburg, I. V., Ross, M., Seifert, F. A., Zussman, J., Aoki, K. and Gottardi, D., 1988- Nomenclature of pyroxenes. American Miniralogist, 62: 53-62.
O’Brien, P. J., 1997- Garnet zoning and reaction textures in overprinted eclogites, Bohemian Massif, European Variscides: A record of their thermal history during exhumation. Lithos 41, 119-133.
Otten, M. T., 1984- The origin of brown hornblende in the Artfjället gabbro and dolerites. Contribution to Mineralogy and Petrology, 86: 189-199.
Ravna, E. K., 2000- Distribution of Fe2+ and Mg between coexisting garnet and hornblende in synthetic and natural systems: an empirical calibration of the garnet–hornblende Fe–Mg geothermometer. Lithos 53: 265–277.
Sengupta, P., Dasgupta, S., Bhattacharya, P. K. and Hariya, Y., 1989- Mixing behavior in Quaternary garnet solid solution and an extended Ellis and green garnet-clinopyroxene geothermometer. Contribution to Mineralogy and Petrology, 103: 223-227.
Spear, F. S., 1980- The gedrite-anthophyllite solvus and the composition limits of orthoamphibole from the Post Pond Volcanics, Vermont. American Mineralogist, 65: 1103-1118.
Stockli, D. F., Hassanzadeh, J., Stockli, L. D., Axen, G., Walker, J. D. and Dewane, T. J., 2004- Structural and geochronological evidence for Oligo-Miocene intra-arc low-angle detachment faulting in the Takab-Zanjan area, NW Iran. Abstract, Programs Geological Society of America, 36: 319.
Stocklin, J., 1968- Structural history and tectonics of Iran: a review: American Association of Petroleum. Geologists Bulletin, 52: 1229–1258.
Scientific Quarterly Journal of Geosciences
Volume 26, Issue 104
VOL.26, NO104
September 2017
Pages 29-42
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