Petrology, geochemistry and petrogenesis of intrusive rock units of Varcheh, SE Arak, Iran.

Saeed Naeemi; Mohammad-Ali Arian; Nader Kohansal-Ghadimvand

Saeed Naeemi Department of geology, faculty of science, North Tehran Branch, Islamic Azad University, Tehran, Iran
Mohammad-Ali Arian Department of geology, faculty of science, North Tehran Branch, Islamic Azad University, Tehran, Iran
Nader Kohansal-Ghadimvand Department of geology, faculty of science, North Tehran Branch, Islamic Azad University, Tehran, Iran

Keywords: Petrogenesis, geochemistry, tertiary intrusive rocks, Varcheh, Iran.

Abstract

The area covering south and southeast Arak toward north Khomein, there are several intrusive igneous rocks including gabbro and monzodiorite units. Intrusive units consists of gabbro to diorite. These intrusive units belong to tertiary period. Over 120 samples were collected from the outcrops and thin section studies and geochemical analysis were carried out as well. 14 samples have been sent for ICP and basic melt analysis for studying major and rare earth elements. The results are compiled by related software. As far as mineralogy is concerned, plagioclase, pyroxene (augite type) and orthoclase are the dominant minerals recognized in the samples. Petrological and mineralogical similarities among the studied samples may suggest a presence of a huge gabbro-diorite batholith between Arak and Khomein. The outcrops of this batholith can be seen in the studied area as a result of erosion. In the other word, some fingerprints of a huge batholite can be observed in the studied area.

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Author Biographies

Saeed Naeemi, Department of geology, faculty of science, North Tehran Branch, Islamic Azad University, Tehran, Iran

Department of geology, faculty of science, North Tehran Branch, Islamic Azad University, Tehran, Iran

Mohammad-Ali Arian, Department of geology, faculty of science, North Tehran Branch, Islamic Azad University, Tehran, Iran

Department of geology, faculty of science, North Tehran Branch, Islamic Azad University, Tehran, Iran

Nader Kohansal-Ghadimvand, Department of geology, faculty of science, North Tehran Branch, Islamic Azad University, Tehran, Iran

Department of geology, faculty of science, North Tehran Branch, Islamic Azad University, Tehran, Iran

References

Aghanabati, A. (2006). Geology of Iran, Geological Survey and Mineral Exploration. Country Publications, Tehran.

Boynton, W.V. (1984). Cosmochemistry of the rare earth elements; meteorite studies. In: Rare earth element geochemistry. Henderson, P. (Editors), Elsevier Sci.

Cabanis, B. & Lecolle, M. (1989). Le diagramme La/10-Y/15-Nb/8: Un outil pour la discrimination des series volcaniques et lamise en evidence des processus demelange et/ou de contamination crustale. Compte Rendus de I’Académie des Sciences Series II, 309, 2023-2029.

Cox, K. G., Bell, J. D.,& Pankhurts, R. J. (1979). The interpretation of igneous rocks. George Allen and Unwin., 450 pp.

De La Roche, H., Leterrier, J., Grandclaude, P., & Marchal, M.(1980). A classification of volcanic and plutonic rocks using R1R2-diagram and major-element analyses--Its relationships with current nomenclature: Chemical Geology, v. 29, p. 183-210.

Fenner, C, N. (1948). Incandescent tuuf flows in southern Peru. Geological society of America. Bulletin, V. 59, pp. 879-893.

Harker, A. (1909). The Natural History of Igneous Rocks. Methuen and Co., London.

Kholghi. M. H.(2004). 1:100K geological map of Varcheh and Khomein, Geological Survey of Iran.

Meschede, M.(1986). A method of discriminating between different types of mid-ocean ridge basalts and continental tholeiites with the Nb-Zr-Y diagram: Chemical Geology, Vol. 56, PP. 207-218.

Middlemost, E. A. K. (1985). Magma and magmatic rocks, An Introduction to igneous petrology. Longman Group U.K., pp. 73 – 86.

Middlemost, E. A. K.(1994). Naming materials in the magma / igneous rock system. Longman Groun u. k., 73 – 86.

Nakamura, N.(1974). Determination of REE, Ba, Fe, Mg, Na and K in carbonaceous and ordinary chondrites. Geochim Cosmochim Acta., Vol. 38, pp. 757-775.

Pearce, J.A. (1983). Role of the sub-continental lithosphere in magma genesis at active continental margins. In: Hawkesworth, C.J., Norry, M.J. (Eds.), Continental Basalts and Mantle Xenoliths, Shiva. Cheshire, UK, pp. 230-249.

Pearce, J.A., Harris, N.B.W., & Tindle, A.G.(1984). Trace element discrimination diagrams for the tectonic interpretation of granitic rocks: Journal of Petrology, v. 25, p. 956-983.

Peccerillo R.,& Taylor S. R. (1976). Geochemistry of Eocene calk – alkaline volcanic rocks from the Kastamonu area, northern Turkey. Contrib. Mineral. Petrol., V 58, pp. 63 – 81.

Rollinson, H. (1993). The Geochemistry of Mafic and Ultramafic Rocks from the Archaen Greenstone Belts of Sierra Leone.

Shervais, J. W. (1982). Ti–V plots and the petrogenesis of modernophiolitic lavas. Earth Planet. Sci. Lett. 59, pp. 101–118.

Streckeisen A.,& Le Maitre R. (1979). A chemical approximation to the modal QAPF classification of igneous rocks. Neues jahrb. Mineral Abh. 136, 169 – 206.

Thompson, R, N. (1982). British Tertiary volcanic province. Scoot. J. Geol., 18, pp. 49 – 107.

Vaezipour. M. J.(1985). 1:100K geological map of Varcheh and Khomein, Geological Survey of Iran.

Wilson, M. (1989). Igneous petrogenesis a global tectonic approach. Department of earth science, University of leeds. 466pp.