Petrology and geochemistry of volcanic rocks in south Langrood

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Research Paper 01/12/2014
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Petrology and geochemistry of volcanic rocks in south Langrood

Sedigheh Ehsani, Mohammad Ali Arian, Mohammad Hossein Razavi
J. Bio. Env. Sci.5( 6), 345-352, December 2014.
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This region is located 330kmfar from north of Tehran in Gilan province. According to tectono-sedimentary classification of Iran (Nabavi, 1977), this region is located in Alborz-Azarbaijan zone. The area of understudied region in Gilan province is 450 km2 that is located in south and west part of Amlash city. In this region the upper part is formed of an Ophiolite set that its uplifting time is upper Cretaceous. Constitutive rocks of this part are rocks of old ocean crust and totally consist of carbonate cretaceous sedimentary rocks, pillow basalts (include basalt, basaltic andesite, andesite and trachyte terms), delorite and gabbro dikes. Totally it can be concluded that petrologic and geochemical studies in southern of Amlash indicate a magmatic event in various tectonic environments in a way that each rift environments, active continental and intra-plate margins are acceptable for some of the samples. In the other hand, there are evidences that show magmatic differentiation and crust pollution happened in understudied rocks. Therefore, clear and detailed interpretation about tectonic environment of these magmatic events is not possible.


Darvishzadeh A, Asiabanha A. 1992 Magmas and magmatic rocks, the basis for igneous petrology. University of Tehran pub, 2190.

Eftekharnejad J. 1981. Separation of various parts of Iran from structural aspect in relation with sedimentary basins, Oil association journal, 82.

Irvin TN, Baragar WRA. 1971. A guide to the chemical classification of the common volcanic rocks. Canadian Journal of Earth Sciences., 8, 523-548.

Le Bas MJ, Le Maitre RW, Streckeisen A, Zanettin B. 1986. A chemical classification of volcanic rocks based on the total alkali-silica diagram.Journal of Petrology 27,445-450.

Nabavi MH. 1977. An introduction to Iran’s geology, Geology organization of Iran, 109.

Oconnor JT. 1965. Aclassification for quartz –rich igneous rock based on feldspar ratios.U.S. Geol.Surv.Prof. Paper 525B , B79-B84

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

Rahmati, Moussvai. 2005. Langrood 1:100000 geological map. Geology and mineral explorations organization.

Rollinson H. 1993-Using geochemical data: Evalution, presentation, interpretation. Longman. 352p.

Sun S, McDonough WF. 1989. Chemical and isotopic systematics of oceanic basalts: Implications for mantle composition and processes. In: Saunders , A.D., Norry, M.G.(EDS.),Magmatism in the Oceans Basins. Geologycal Society of London Publication, 313 -345.

Taylor SR, M Mclennan. 1985. The continental crust :its compositon and evolution, BlackwelSci. Pup. Oxford, 312p.

Wilson M. 1989, Igneous petrogenesis-Aglobal tectonic approach. Unwin Hyman London, 466p.

Winchester JA, Floyd PA. 1976. Geochemical discrimination of different magma series and their differention product using immobile elemnts.Chemical Geology.20, 325-343.

Wood DA. 1980.  The  application  of  a  Th-Hf-Ta diagram to problems of tectenomagmatic classification and establishing the nature of crustal contamination of basaltic lavasof the British Tertiary volcanic province. Earth Planet.Sci.Lett. 50, 11-30.