Petrology, mineral chemistry and tectono-magmatic setting of volcanic rocks from northeast Farmahin, north of Arak

زمین شناسی اقتصادی

Article 7, Volume 6, Issue 2 - Serial Number 11, January 2015, Pages 375-392   

Document Type: Research Article

DOI: 10.22067/econg.v6i2.25969

Authors

Reza Zarei Sahamieh^* ; Sara Ebrahimi

Lorestan

Abstract

Introduction
The study area is a small part of the Urumieh-Dokhtar structural zone in the Markazi province, located in the northeastern part of the Farmahin, north of Arak (Hajian, 1970). The volcanic rocks studied from the area include andesite, dacite, rhyodacite, ignimbrite and tuff of Middle to Late Eocene age (middle Lutetian to upper Lutetian) (Ameri et al., 2009). It seems that folding and faulting is caused in sedimentary basin and volcanic activities. On the other hand, except of orogeny maybe rifting had rule in eruption so that this case has seen in the other area such as Taft and Khezrabad in central Iran (Zarei Sahamieh et al., 2008). The oldest formation in the studied area is Triassic limestones. The dominant textures of these rocks are porphyritic, microlite porphyritic, microlitic and rarely sieve-texture. Sieve texture and dusty texture (dusty plagioclases) indicates magma mixing. Mineralogically, they contain plagioclases, clinopyroxenes, amphiboles, quartz and biotite as the main constituents and zircon, apatite, and opaque minerals as accessories. Plagioclases in the andesitic and basaltic- andesite rocks are labradorite, bytownite and anorthite (based on electron microprobe) .Moreover, plagioclases in andesitic rocks show that H2O is lesser than 2.5 precent. Amphibole is found in both plagioclases and groundmass.

Materials and methods
In this article are used different analyses methods such as XRF, ICP-MS and EPMA.
Whole-rock major and trace element analyses were determined with ICP-MS method.
The major and trace element composition of some rock was determined by electron probe micro-analysis (EPMA) using a Cameca SX100 instrument in Iran Mineral Processing Research Center (IMPRC). Moreover, whole-rock major and some trace element analyses for some samples were obtained by X-ray fluorescence (XRF), using an ARL Advant-XP automated X-ray spectrometer.

Results
Chemical data based on electron micro probe studies of minerals indicate the presence of labradorite, bytownite, anorthite as the plagioclases in volcanic rocks, as well as augite, pigeonite and clinoenstatite among the pyroxenes are abundant. Microscopic study of these lavas and pyroclastic rocks show evidences of magmatic contamination in the form of oscillatory zoning, resorption rims in plagioclase and presence of basic inclusions. The presence of oxidized amphibole rims (in hornblende) indicates the high temperature of the magma at the time of eruption.
Based on geochemistry especially the ratio of Eu/Eu* is variable between liquid and solid phases. The calculated of this ratio in studied rocks show negative anomaly (Eu

Keywords

Farmahin; calc-alkaline; continental margin; orogenic

References

Ahmadian, J., Bahadoran, N., Torabi, G. and Morata, M., 2010. Geochemistry and petrogenesis of volcanic rocks in Aroosan Kabood (north-east of Anarak). Journal of Petrology, 1(1): 103-120. (in Persian)

Ameri, A., ashrafi, N. and Karimi qarebaba, H., 2009. Petrology, Geochemistry and tectonics environment of Eocene volcanic rocks in east of Herris, east Azerbayjan, north-west of Iran. Journal of geosciences, 18(71): 85-90. (in Persian)

Barth, M.G., Foley, S.F. and Horn, I., 2002 . Partial melting in Archean subduction zones: constraints from experimentally determined trace elements partition coefficients between ecologitic material and tonalitic melts under upper mantle conditions. Precambrian Research, 113(3-4): 323-340.

Berberian, F. and Berberian, M., 1981 .Tectonoplutonic episodes in Iran. In: H.K. Gupta and F.M. Delany (Editors), Zagros Hindukush, Himalaya Geodynamic Evolution. American Geophysical Union, Washington DC, pp. 5-32.

Clarke, D.B., 1992. Granitoid Rocks. Chapman & Hall, New York, 283 pp.

De La Roche, H., Laterier, J., Grand Claude, P. and Marchel, M., 1980. A classification of volcanic and plutonic rocks using R1-R2 diagrams and major elements- Its relationships with current nomenclature. Chemical Geology, 29(1-4): 183-210

Emami, M.H., 1991. Geological map of Qom (1/100000). Geological Survey of Iran.

Ghasemi, A. and Talbot, C.J., 2006. A new scenario for the Sanandaj-Sirjan zone (Iran). Journal of Asian Earth Sciences, 26(6): 683-693.

Gill, J.B., 1981. Orogenic Andesites and Plate Tectonics. Minerals and Rocks, 16. Spring-verlag, Berlin, Heidelberg, New York, 390 pp.

Gioncada, A., Hauser, N., Matteini, M., Mazzuolir, M. and Omarini, R., 2006. Mingling and mixing features in basaltic andesites of the eastern Cordillera (central Andes, 24S): a petrographic and microanalytical study. Periodico di Mineralogia, 75(2-3): 127-140.

Hajian, J., 1970 . Geological map of Farmahin (1/100000). Geological Survey of Iran.

Ionov, D.A. and Hoffmann, A.W., 1995. Nb–Ta-rich mantle amphiboles and micas; implication for subduction- related metasomatic trace element fractionations. Earth and Planetary Science Letters, 131(3-4): 341–356.

Irvine, T.N. and Baragar, W.R.A., 1971. A guide to the chemical classification of the common volcanic rocks. Canadian Journal of Earth Sciences, 8(5:( 523-548.

Kelemen, P.B., Hanghoj, K. and Greene, A.R., 2004. One View of the Geochemistry of Subduction related Magmatic Arcs, with an Emphasis on Primitive Andesite and Lower Crust. Treatise on Geochemistry, 3: 593-659.

Le Bas, M.J., Le Maitre, R.W., Streckeisen, A. and Zanettin, B., 1986. Achemical classification of volcanic rocks based on the total alkali silica diagram. Journal of Petrology, 27(3): 745-750.

Li, X., Mo, X., Yu, X., Ding, Y., Huang, X., Wei, P., He, W., 2013. Petrology and geochemistry of the early Mesozoic pyroxene andesites in the Maixiu Area, West Qinling,China: Products of subduction or syn-collision. Lithos, 172-173: 158-174.

Pearce, T.H., Gorman, B.E. and Birkett, T.C., 1977. The relationship between major element geochemistry and tectonic environment of basic and intermediate volcanic rocks. Earth and Planetary Science Letters, 36(1): 121–132.

Pitcher, W.S., Atherton, M.P., Cobbing, E.J. and Beckinsale, R.D., 1985. Magmatism at a Plate Edge: the Peruvian Andes. Blackie, London, 328 pp.

Riecker, R.E., Zimmerman, C. and Kudo ,A., 2013. Geochemistry of Andesites and Related Rocks, Rio Grande Rift, New Mexico. American Geophysical Union, New Mexico, 438 pp.

Rollinson, H.R., 1993. Using Geochemical Data: Evaluation, Presentation and Interpretation. Longman scientific and technical, London, 352 pp.

Rollinson, H.R., (translated by Karimzadeh Samarin, A.), 2003. Using geochemical data: evaluation, presentation, interpretation. Tabriz University Press, Tabriz, 557 pp. (in Persian)

Roozbehani, L. and Arvin, M., 2010. Petrography, geochemistry and petrogenesis of ryolitic and andesitic rocks in Nasir Abad, south-west, Kerman .Journal of Petrology, 1(2): 1-16. (in Persian).

Saunders, A.D., Tarncy, J. and Weaver, S.D., 1980. Transverse geochemical variations across the Antarctic Peninsula: implications for the genesis of calc-alkaline magmas. Earth and Planetary Science Letters, 46(3): 344-360.

Shelley, D., 1993. Igneous and metamorphic rocks under the microscope. Chapman & Hall, University Press, Cambridge, Great Britain, 445 pp.

Tabatabai Manesh, M., Sayed Safai, H. and Mirlohi, A.S., 2010. Study of mineralogy and effective process on volcanic rocks in Jahaq anticlinal (south of Kashan). Journal of Petrology, 1(2): 61-76. (in Persian)

Tsuchiyama, A., 1985. Dissolution Kinetics of plagioclase in the melt of the system diopside -albite -anorthite, and origin of dusty plagioclase in andesite. Contributions to Mineralogy and Petrology, 89(1): 1-16.

White, P. J., 1985. Age, petrology and geochemistry of Wairakau Andesites, Whangaroa, Northland. New Zealand Journal of Geology and Geophysics, 28(4): 635-647.

Wilson, M., 1989. Igneous petrogenesis A global tectonic approach. Unwin Hyman, London, 466 pp.

Winchester, J.A. and Floyd, P.A., 1977. Geochemical discrimination of different magma series and their differentiation products using immobile elements. Chemical geology, 20: 325-343.

Yoshida,T., Okamura, S., Sakamoto, I., Ikeda, Y., Adachi, Y., Kojima, M., Sugawara, M. and Shitahaku, R., 2013. Petrology of felsic rocks dredged from the Myojin Seamount and the Myojin Rift in the north Izu-Bonin arc - Contribution of intra-oceanic subduction system to making continental middle crust. Meeting of International Association of Volcanology and Chemistry of the Earth's Interior‌, Kagoshima, Japan.

Zarasvandi, A., Liaghat, S. and Zentilli, M., 2005. Geology of the Darreh-Zerreshk and Ali-Abad Porphyry Copper Deposits, Central Iran. International Geology Review, 47(6): 620-645.

Zarei Sahamieh, R., Tabasi, H. and Jalali, M., 2008. Petrology and tectonomagmatic investigation of volcanic rocks of Ashtian. Journal of Science Kharazmi University, 8(3):227-240. (in Persian)