Document Type : Original Research Paper


1 Department of Hydrology, Agriculture Faculty, University of Mohaghegh Ardabili, Ardabil, Iran

2 Department of Geology, Natural Science Faculty, University of Tabriz, Tabriz, Iran.

3 Department of Geology, University of New Brunswick, Canada.


In this paper the study of Plio-Quaternary post-collisional magmatism in northwest of Iran and northwest of Marand is considered. The studied Potassic and ultrapotassic (UP) alkaline rocks were erupted at northern part of Urumieh-Dokhtar magmatic arc (UDMA). The studied rocks dispaly microlithic porphyritic texture with phenocrysts of clinopyroxene, leucite, and plagioclase ± biotite ± olivine. The UP volcanic rocks are mostly silica undersatuated with normative nephline, high Mg# and high K2O/Na2O ratios. They characterized with significant enrichment in LILEs and LREEs and depletion in high field strength elements such as Nb, Ta and Ti. Exhibit high Ba/Nb (41-60) and Ba/Ta (682-1139) ratios, which are a typical feature of subduction. With considering end of subduction (upper cretaceouse) and stratigraphic age of studed rocks (plio-quaternary), we can say that these rocks has formed in post collisional environment and metasomatic mantle due to addition of volatiles and incompatible elements lead to enrichment of these magmas. And in fact we can say that the subduction properties of these rocks inherited from an ancient subduction. On the otherhand, high contents of LILE such as Th and Ba and Ba/Nb, Ba/Ta ratios indicate the involvement of crustal components in genesis of these rocks by addition of crustal components to source and contamination through ascent of magma. Rare earth elements modeling indicate that they can be generated from low degree partial melting of lithospheric mantle with garnet-spinel peridotite source.


Agard, P., Omrani, J., Jolivet, L. & Mouthereau, F., 2005- Convergence history across Zagros (Iran): constraints from collisional and earlier deformation. International Journal of Earth Sciences 94, 401–419.
Alavi, M., 1994- Tectonics of the Zagros Orogenic belt of Iran: new data and interpretations.   Tectonophysics 220, 211–238.
Alavi, M., 2004- Regional stratigraphy of the Zagros fold-thrust belt of Iran and its proforeland evolution. American Journal of Science 304, 1–20.
Aldanmaz, E., Pearce, J. A., Thirwali, M. F. & Mitchel, J. G., 2000- Petrogenetic evolution of late Cenozoic post-collision volcanism in western Anatolia, Turkey. Journal of Volcanology and Geothermal Research 102, 67-95.
Alici, P., Temel, A., Gourgaud, A., Vidal, P. & Gundogdu, M. N., 2001- Quaternary Tholeitic to alkaline volcanism in the Karasu valley (Hatay), N-end of Dead sea Rift zone in SE Turkey: Sr-Nd-Pb-O isotopic and trace element approaches to crust mantle interaction. International Geology Review 43(2), 120-38.
Amidi, S. M., Emami, M. H. & Michel, R., 1984- Alkaline character of Eocene volcanism in the middle part of Central Iran and its geodynamic situation. Geologische Rundschau 73, 917–932.
Berberian, F. & Berberian, M., 1981- Tectono-plutonic episodes in Iran. In: Gupta, H.K., Delany, F.M. (Eds.), Zagros, Hindukosh, Himalaya. Geodynamic Evolution. American Geophysical Union, Washington, DC, pp. 5–32.
Berberian, F., Muir, I. D., Pankhurst, R. J. & Berberian, M., 1982- Late Cretaceous and early Miocene Andean type plutonic activity in northern Makran and central Iran. Journal of Geological Society of London 139, 605–614.
Boudier, F., Ceuleneer, G. & Nicolas, A., 1988- Shear zones, thrusts and relatedmagmatism in the Oman ophiolite: initiation of thrusting on an oceanic ridge. Tectonophysics 151, 275–296.
Boynton, W. V., 1984- Geochemistry of the rare earth elements: meteorite studies. In: Henderson, P. (Ed.), Rare Earth Element Geochemistry. Elsevier, pp. 63– 114.
Coleman, R. G., 1971- Plate tectonic emplacement of upper mantle peridotites along continental edges. Journal of Geophysical Research 76, 1212–1222.
Emami, H., 1981- Geologie de la reigon de Qom-Aran (Iran) contribution a l’ etude denamique et geochemique du volcanisme Teriaire de l’ Iran centaral. Unpublished Ph.D these, University Sc. Et Medical de Grenoble, 489 pp.
Farhoudi, G., 1978- A comparison of Zagros geology to island arcs. Journal of Geology 86, 323–334.
Green, N. L., 2006- Influence of slab thermal structure on basalt source regions and melting conditions: REE and HFSE constraints from the Garibaldi volcanic belt, northern Cascadia subduction system. Lithos 87, 23-49Jahangiri, A. 2007. Post-collisional Miocene adakitic volcanism in NW Iran: Geochemical and geodynamic implications. Journal of Asian Earth Sciences xxx (2007) xxx–xxx
Homke, S., Verges, J., Garces, M., Emami, H. & Karpuz, R., 2004- Magnetostratigraphy of Miocene–Pliocene Zagros foreland deposits in the front of the Push–e Kush Arc (Lurestan Province, Iran). Earth and Planetary Science Letters 225, 397–410.
Jahangiri, A., 2007- Post – Collisional Miocene adakitic volcanism in NW Iran: geochemical and geodynamic implications. Journal of Asian Earth Sciences 30, 433-447.
Jung, D., Kursten, M. & Tarkian, M., 1976- Post-Mesozoic volcanism in Iran and its relation to the subduction of the Afro-Arabian under the Eurasian plate. In: Pilger, A., Rosler, A. (Eds.), A far Between Continental and Oceanic Rifting. Schweizerbartsche Verlagbuchhandlung, Stuttgart, pp. 175–181.
Le Bas, M. J., Le Maitre, R. W., Streckeisen, A. & Zanettin, B., 1986- A chemical classification of volcanic rocks based on the total alkali-silica diagram. Journal of Petrology  27, 445-450.
McCulloch, M. T. & Gamble, J. A., 1991- Geochemical and geodynamical constraints on subduction zone magmatism: Earth and Planetary Science Letters 102, 358-374.
McCulloch, M. T., 1993- The role of subducted slabs in an evolving Earth: Earth and Planetary Science Letters 115, 89-100.
McKenzie, D. P. & O'Nions, R. K., 1991- Partial melt distribution from inversion of rare earth element concentrations. J. Petrol. 32, 1021-1991.
McKenzie, D. P. & O'Nions, R. K., 1995- The source regions of Ocean Island Basalts. Journal of  Petrology 36, 133-159.
Moayyed, M., Moazzena, M.,  Calagari, A. A., Jahangiri, A. &  Modjarrad, M., 2007- Geochemistry and petrogenesis of lamprophyric dykes and the associated rocks from Eslamy peninsula, NW Iran: Implications for deep-mantle metasomatism. Chemie der Erde, in press.
Molinaro, M., Leturmy, P., Guezou, J. C., Frizon de Lamotte, D., Eshraghi, S. A., 2005a- The structure and kinematics of the southeastern Zagros fold–thrust belt, Iran: from thin-skinned to thick-skinned tectonics. Tectonics 24. doi:10.1029/2004TC001633.
Muller, D., Rock, N. M. S. & Groves, D. I., 1992- Geochemical discrimination between shoshonitic and potassic volcanic rocks from different tectonic setting: a pilot study. Mineralogy and Petrology 46, 259-289.
Murphy, J. B., 2007- Igneous Rock Associations and Arc Magmatism II: Geochemical and Isotopic Characteristics. Geoscience Canada.
Nicolas, A., 1989- Structures in Ophiolites and Dynamics of Oceanic Lithosphere. Kluwer, Dordrecht. 367 pp.
Omrani, J., Agard, P., Whitechurch, H., Benoit, M., Prouteau, G. and Jolivet, L., 2008- Arc-magmatism and subduction history beneath the Zagros Mountains, Iran: A new report of adakites and geodynamic consequences, Lithos (2008), doi: 10.1016/j. lithos.2008.09.008.
Pearce, J. A. & Peate, D. W., 1995- Tectonic implications of the composition of volcanic arc magmas. Annu. Rev. Earth Planet. Sci. 23, 251-285.
Pearce, J. A., 1983- Role of the sub-continental lithosphere in magma genesis at active continental margins. In: C.J. Hawkesworth & M.J., Norry, eds.Continental Basalts and Mantle Xenoliths. Shiva Press, Nantwich, U.K., pp 230-249.
Ricou, L. E., 1971- Le croissant ophiolitique péri-arabe, une ceinture de nappes mise en place au crétacé supérieur. Revue de géographie physique et de géologie dynamique 13, 327–350.
Rollinson, H., 1993- Using geochemical data: Evalution, presentation, interpretation. Longman. 352 pp.
Saunders, A. D. & Tarney, J., 1984- Geochemical characteristics of basaltic volcanism in back-arc basins. In Kokelaar, B.P., and Howells, M.F., (Eds). Marginal Basin Geology: Volcanic and Associated Sedimentary and Tectonic Processes in Modern and Ancient Marginal Basins: Geological Society of London, Special Publication 16, 59-76.
Saunders, A. D., Norry, M. J. & Tarney, J., 1988- Origin of MORB and chemically-depleted mantle reservoirs: trace element constrainst. Journal of petrology, Special Lithosphere Issue 415–445.
Saunders, A. D., Norry, M. J. & Tarney, J., 1991- Fluid influence on the trace element composition of subduction zone magmas: Philosophical Transactions of the Royal Society of London 335, 377-392.
Saunders, A. D., Tarney, J. & Weawer, S. D., 1980- Transverse geochemical variations across Antarctic Peninsula: implications for the genesis of calc-alkaline magmas. Earth and Planetary Science Letters 46, 344–360.
Searle, M. P. & Cox, J., 1999- Tectonic setting, origin and obduction of the Oman ophiolite. Geological Society of America Bulletin 111, 104–122.
Shaw, D. M., 1970- Trace element fractionation during anatexis. Geochim. Cosmochim. Acta 34, 237-243.
Sun, S. S. & McDonough, W. F., 1989- Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. In: Saunders, A.D., Norry, M.J. (Eds.). Magmatism in the Ocean Basins, Geol. Soc., London, Spec. Publ. 42, pp. 313±345.
Thompson, R. N., Morrison, M. A., Dickin, A. P. & Hendry, G. L., 1983- Continental flood basalts… arachnids rule OK? In continental basalts and mantle xenoliths (eds C. J. Hawkesworth and M. J. Norry), pp. 158-85. Nantwich, Cheshire: Shiva Publishing Limited.
Whitechurch, H., Juteau, T. & Montigny, R., 1984- The eastern mediterranean ophiolites (Turkey, Syria, Cyprus): their contribution to the history of the Neo-Tethys. In: Dixon, J.E., Robertson, A.H.F. (Eds.), The Geological Evolution of the Eastern Mediterranean. Geological Society Special Publication, Oxford, pp. 425–441.
Wilson, M., 1989- Igneous Petrogenesis, a Global Approach. Unwin Hyman London.
Woods, S. C.,  Lotter, E. C.,  Mckay, L. D. &  Porte, D. Jr., 1979- Chronic intracerebroventricular infusion of insulin reduces food intake and body weight of baboons. nature 282, 503 - 505 (29 november 1979); doi:10.1038/282503a0