Siah Kooh area is northeast of Shahroud city and is located in eastern Alborz. The lithologic composition of the volcanic rocks in the area consists of andesite, basalt, trachyandesite and quartztrachite. Plagioclase, olivine, and augite phenocrysts as the main minerals and apatite and magnetite, sericite, chlorite and apacite minerals are sub-minerals of volcanic rocks that are located in the glass slabs. Quartz is also found in fine-grained rock pulp and sometimes in phenocrysts. The dominant texture in these rocks are porphyritic, amygdaloidal and microlithic. According to geochemical studies of basaltic magmatic volcanic rocks, calc-alkaline potassium is high and negative Nb anomaly, Ce / Pb ratio and enrichment of rocks of light rare earth elements (LRRE) and high LREE / HREE ratio indicate contamination. The crust is an indicator of the presence of the garnet phase in the mantle source. On the other hand, the similarity of their trace elements to Oceanic Basalts (OIB) is a clear evidence of their relevance to this environment. Early basaltic magma originated from a mantle with a garnet-lherzolite composition with a partial melting rate of 15–12%. FeOtotal values in basalts and other structural evidence indicate the formation of these rocks in the early stages of intra-continental rifting which can be attributed to the pressure drop caused by intra-continental tidal phases associated with deep faults during the orogenic phases. Alpine attributed to Eocene time.

Author Biographies

Mohammad Ali Arian, Islamic Azad University, Iran

Associate Professor, Department of Geology, North Tehran Branch, Islamic Azad University, Tehran, Iran.

Mostafa Baratian, Islamic Azad University, Iran

PhD Candidate of Petrology, Department of Geology, North Tehran Branch, Islamic Azad University, Tehran, Iran.

Abdollah Yazdi, Islamic Azad University, Iran

Assistant Professor, Department of Geology, Kahnooj Branch, Islamic Azad University, Kahnooj, Iran.


ALLEN, M. B., GHASSEMI, M. R., SHAHRABI, M. & QORASHI, M. Accommodation of Late Cenozoic oblique shortening in the Alborz range, northern Iran”, 2003. Journal of Structural Geology Vol.25. PP., 659-675.

ALLEN, M. B., STEPHEN, J. V., ALSOP, G., ISMAIL ZADEH, A. & FLECKER, R. b-late Cenozoicdeformation in the South Caspian region: effects of a rigid basement block within a collision zone. 2003. Tectonophysics, V. 366, P. 223-239.

ARFANIA, Ramin. Role of supra-subduction zone ophiolites in the tectonic evolution of the southeastern Zagros Orogenic Belt, Iran, 2018. Iranian Journal of Earth Sciences, 10(1) pp 31-38.

ASHRAFI, Nasser; HASEBE, Noriko; JAHANGIRI, Ahmad. Cooling history and exhumation of the Nepheline Syenites, NW Iran: Constraints from Apatite fission track, 2018. Iranian Journal of Earth Sciences, 10(2) pp 109-120.

ASIABANHA, A.; FODEN, F. Post-collisional transition from an extensional volcano-sedimentary basin to a continental arc in the Alborz ranges, N-Iran, 2012, Lithos, 148, 98–111.

AZIZI, H., HADAD, S., STERN, R., ASAHARA, Y. Age, geochemistry, and emplacement of the ~40-Ma Baneh granite–appinite complex in a transpressional tectonic regime, Zagros suture zone, northwest Iran. 2018. International Geology Review, DOI: 10.1080/00206814.2017.1422394

COX, K. G., BELL, J. D. & PANKHURST, R. J. The Interpretation Igneous rocks. London: George Allen & Unwin, 1979.

DABIRI, Rahim; AKBARI-MOGADDAM, Mohsen; GHAFFARI, Mitra. Geochemical evolution and petrogenesis of the eocene Kashmar granitoid rocks, NE Iran: implications for fractional crystallization and crustal contamination processes, Iranian Journal of Earth Sciences, 10(1) pp 68-77. 2018.

GLASSER, N.; BENNET. R.M.; HUDDART, D. Distribution of glaciofluvial sediment within and on the surface of a high arctic valley glacier: Marthabreen, Svalbardh. 1999. Journal of Earth surface processes and landforms. Vol. 24., pp. 303-318.

GLAZNER, A. F.; W. USSLER III. Crustal extension, crustal density, and the evolution of Cenozoic magmatism in the Basin and Range of the western United States, 1989. J. Geophys. Res., 94, 7952–7960, doi:10.1029/ JB094iB06p07952.

GREEN, L. 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. 2006. Journal of Lithos, 87, 23– 49pp.

GUEST, B.; GUEST, A.; AXEN, G. Late Tertiary tectonic evolution of northern Iran: A case for simple crustal folding. 2007. Journal of Global and Planetary Change 58: 435-453.

HUMPHREYS, E., E. HESSLER, K. DUEKER, G. L. FARMER, E. ERSLEV, AND T. ATWATER. How Laramide‐age hydration of North American lithosphere by the Farallon slab controlled subsequent activity in the western United States. 2003. Int. Geol. Rev., 45, 575–595, DOI:10.2747/0020- 6814.45.7.575.

IRVINE, T. N. & BARAGAR, W. R. A. A Guide to the chemical classification of the common Volcanic Rocks. 1971. Canadian Journal of Earth Science 8: 523-548.

PEARCE J.A. Role of the sub-continental lithosphere in magma gensis at activevcontinental margins. In: HAWKESWORTH C. J.; NORRY M. J. (eds.). Continental basalts and Mantle Xenoliths. Shiva ,Natwich, 1983, p. 230–249.

PLANK, T.; C. H. LANGMUIR. An evaluation of the global variations in the major element chemistry of arc basalts. 1988. Earth Planet. Sci. Lett., 90, 349–370, DOI:10.1016/0012-821X(88)90135-5.

STÖCKLIN, J. Structural history and tectonics of Iran: A review. 1968. American Association of Petroleum Geologists, v.52, p. 1229–1258.

SUN, S. S.; MCDONOUGH, W. F. 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. 1989. Geol Soc Spec Publ., vol. 42, p. 313-345.

TAPPA, M.J., COLEMAN, D.S., MILLS, R.D., AND SAMPERTON, K. M. The plutonic record of a silicic ignimbrite from the Latir volcanic field, New Mexico. 2011. Geochemistry, Geophysics, Geosystems, v. 12, no. 10, Q10011, DOI: 10.1029/2011GC003700.

TEMIZEL, I; ARSLAN, M. Petrology and geochemistry of Tertiary volcanic rocks from the-Ikizce (Ordu) area, NE Turkey: Implications for the evolution of the eastern Pontide paleo-magmatic arc. 2008. Journal Of Asian Earth Science, 31, pp. 439-463.

WHITE, R. S.; MCKENZIE, D. Mantle plumes and flood basalts. 1995. J Geophys Res., Vol. 100, p. 17543-17585.

YAXLEY, G. M. Experimental study of the phase and melting relations of homogeneous basalt+peridotite mixtures and implications for the petrogenesis of flood basalts. 2000. Contrib Mineral Petr., Vol. 139, p. 326-338.

YAZDI, A.; SHAHHOSINI, E.; DABIRI, R.; ABEDZADEH, H. Magmatic Differentiation Evidences And Source Characteristics Using Mineral Chemistry In The Torud Intrusion (Northern Iran). 2019. Revista GeoAraguaia, 9(2): 6-21.

ZANCHI, A., BERRA, F., MATTEI, M., GHASSEMI, M. R.; SABOURI, J. Inversion tectonics in Central Iran, 2006. Journal of Structural Geology 28: 2023-2037.

ZENG, G., CHEN, L., XU, X., JIANG, SH.; HOFMANN, A. Carbonated mantle sources for Cenozoic intra-plate alkaline basalts in Shandong, North China. 2010. Chem. Geol., Vol. 273, PP. 35-45.

ZONENSHAIN, L. P.; LEPICHON, X. Deep basins of black sea and Caspian Sea as remnants of Mesozoic back-arc basin. 1986. Tectonophysics. 123: 181-211.
How to Cite
ARIAN, Mohammad Ali; BARATIAN, Mostafa; YAZDI, Abdollah. PETROLOGY AND PETROGENESIS OF SIAH KOOH VOLCANIC ROCKS IN THE EASTERN ALBORZ. Geosaberes, Fortaleza, v. 11, p. 349 - 363, may 2020. ISSN 2178-0463. Available at: <>. Date accessed: 19 june 2024. doi: