Document Type : Original Research Paper
Authors
Assistant Professor, Department of Geology, University of Hormozgan, Bandarabbas, Iran
Abstract
The studied area is located in the north of Rudan city, Groom mountain, in the contact area of the Zagros and Makran zones and some part of Kahnuj-Rudan-Minab ophiolite belt. The studied ultramafic rocks include lherzolite and harzburgite, matrix minerals contains olivine, orthopyroxene, clinopyroxene and chromian spinel which is a minor mineral. Based on the geochemical data, the amount of CaO, MgO, TiO2 and V, these rocks belong to non serpentinized orogenic ophiolites. According to microprobe data, the high amounts of Mg#(91.15-93.24) in the lherzolite olivines are indicated that these olivines had refractory and restite, also lherzolite clinopyroxenes are also of the diopside quality, but spinels have poor chromian. Detailed microprobe studies on the spinel of these rocks, ndicated of the high amounts of Mg#(71-77) and Al2O3(52.98 to 46.31Wt%) ) and low Cr#(14-22). Cr/Al proporation of in chromian spinels of lherzolites are equal to 0.19 and amount of Fe3+ in the lherzolite spinels is very low (
Keywords
Main Subjects
References
Ahmadipour, H., Sabzehei, M., Whitechurch, H., Rastad, E. and Emami, M. H., 2003- Soghan complex as an evidence for paleospreading center and mantle diapirism in Sanandaj-Sirjan zone (South-East of Iran). Journal of Sciences, Islamic Republic of Iran 14: 157-172.
Arai, S., 1992- A- Chemistry of chromian spinel in volcanic rocks as a potential guide to magma chemistry. Mineralogical Magazine 56: 173-184.
Arai, S., 1994- Characterization of spinel peridotites by olivine-spinel compositional relationships: Review and interpretation. Chemical Geology 113: 191-204.
Barnes, S. J. and Roeder, P. L., 2001- The Range of spinel compositions in terrestrial mafic and ultramafic rocks. Journal of Petrology 42: 2279-2302.
Batanova, V. G., Suhr, G. and Sobolev, A. V., 1998- Origin of Geochemical Heterogeneity in the Mantle Peridotites from the Bay of Islands Ophiolite, Newfoundland, Canada: Ion Probe Study of Clinopyroxenes. Geochimica et Cosmochimica Acta 62: 853-866.
Beccaluva, L., Ohnenstetter, D. and Ohnenstetter, M., 1979- Geochemical discrimination between ocean-floor and island-arc tholeiites application to some ophiolites. Canadian Journal of Earth Sciences 16: 1874-1882.
Best, M. G., 2000- Igneous and metamorphic petrology, Freeman pub, 325 p.
Conrad, W. K. and Kay, R. W., 1984- Ultramafic and mafic inclusions from Adak Island: Crystallization history and implications for the nature of primary magmas and crustal evolution in the Aleutian arc. Journal of Petrology 25: 88-125.
Dick, H. J. B. and Bullen, T., 1984- Chromian spinel as a petrogenetic indicator in abyssal and Alpine type peridotites and spatially associated lavas. Contributions to Mineralogy and Petrology 86: 54-76.
Downes, H., 2001- Formation and modification of the shallow sub–continental lithospheric mantle: A review of geochemical evidence from ultramafic xenolith suites and tectonically emplaced ultramafic massifs of western and Central Europe. Journal of petrology 42: 233-250.
Droop, G. T. R., 1987- general equation for estimating Fe+3 concentration in ferromagnesian silicates and oxides from microprobe analyses, using stoichiometric criteria. Mineralogical Magazine 51: 431-435.
Eggins, S. M., Rudnick, R. L. and McDonough, W. F., 1998- The composition of peridotites and their minerals: a laser-ablation ICP-MS study. Earth and Planetary Science Letter 154, 53-71.
Emami, M. H., Sadeghi, M. M. and Omrani, S. J., 1993- Magmatic map of Iran, scale 1:1,000,000 Geological Survey of Iran.
Fisk, M. R. and Bence, A. E., 1980- Experimental crystallization of chrome spinel in FAMUS basalt 527-1-1. Earth and planetary science letters 48: 111-123.
Haggerty, S. E., 1988- Upper mantle opaque mineral stratigraphy and the genesis of metasomatites and alkali-rich melts. Journal of Geological Society of Australia 14: 687-699.
Hellebrand, E., Snow, J. E., Dick, H. J. B. and Hoffmann, A. W. , 2001- Coupled major and trace elements as indicators of extent of melting in mid-ocean-ridge peridotites. Nature 410: 677-681.
Hickey, R. L. and Frey, R. A., 1982- Geochemical characteristics of boninite series volcanics: implications for their source. Geochimica et Cosmochimica Acta 46: 2099-2115.
Hill, R. and Roeder, P., 1974- The crystallization of spinel from basaltic liquid as a function of oxygen fugacity. Journal of Geology 82: 709-729.
Kamenetsky, V. S., Crawford, A. J. and Meffre, S., 2001- Factors controlling chemistry of magmatic spinel: An empirical study of associated olivine, Cr-spinel and melt inclusions from primitive rocks. Journal Petrology 42: 655-671.
Kelemen, P. B., Hirth, G., Shimizu, N., Spiegelman, M. and Dick, H. J. B., 1997- A review of melt migration processes in the adiabatically upwelling mantle beneath oceanic spreading ridges. Philosophical Transactions of the Royal Society of London, A. 355: 283-318.
Kepezhinskas, P. K., Defant, M. J. and Drummond, M. S., 1995- Na metasomatism in the island-arc mantle by slab melt-peridotite interaction: evidence from mantle xenoliths in the North Kamchatka arc. Journal of Petrology 36: 1505–1527.
Kornprobst, J., Ohnenstetter, D. and Ohnenstetter, M., 1981- Na and Cr contents in Cpx from peridotites: a possible discriminant between sub-continental and sub-oceanic mantle. Earth and Planetary Science Letters 53: 241-254.
Kretz, R., 1983- Symbols for rock-forming minerals. American Mineralogist 68: 277-279.
Le Bas, M. J., 2000- IUGS reclassification of the high-Mg and picritic volcanic rocks. Journal of Petrology 41: 1467-1470.
McCall, G. G. H., Morgan, K. H. and Huber, H., 1983- Geological Quadrangle Map of Minab, 1:250,000 Series, Sheet J 13, Geological Survey of Iran, Tehran.
McCall, G. J. H., 1985- A- Explanatory text of the Minab Quadrangle Map; 1:250,000; No. J13, Geological Survey of Iran, Tehran, 530 pp.
McCall, G. J. H., 2003- A critique of the analogy between Archaean and Phanerozoic tectonics based on regional mapping of the Mesozoic-Cenozoic plate convergent zone in the Makran, Iran. Precambrian research 127: 5-17.
McDonough, W. F., Stosch, H. G. and Ware, N. G., 1992- Distribution of titanium and the rare elements between peridotitic minerals. Mineralogy and Petrology 110: 321-328.
Melluso, L. and Sethna, S. F., 2011- Mineral compositions in the Deccan igneous rocks of India: An Overview. In: J., Ray, G., Sen, B., Ghosh (Eds.), Topics in igneous petrology. Springer 7: 35-159.
Morimoto, N., 1989- Nomenclature of pyroxenes. The Canadian Mineralogist 27: 143-156.
Najafzadeh, A. R., Arvin, M. Pan, Y. and Ahmadipour, H., 2008- Podiform chromitites in the Sorkhband ultramafic complex, Southern Iran: evidence for ophiolitic chromitite. Journal of Sciences, Islamic Republic of Iran 19: 49-65.
Nicolas, A., 1989- Structure of ophiolites and dynamics of oceanic lithosphere. Kluwer Academic Publishers, Dordrecht, Boston.
Orberger, B., Lorand, J. P., Girardeau, J., Mercier, J. C. C. and Pitragool, S., 1995- Petrogenesis of ultramafic rocks and associated chromitites in the Nan Uttardit ophiolite, Northern Thailand. Lithos 35: 153-182.
Parkinson, I. J. and Pearce, J. A., 1998- Peridotites from the Izu-Bunin-Mariana forearc (ODP Leg 125): evidence for mantle melting and melt-mantle interaction in a supra-subduction zone setting. Journal of Petrology 39: 1577-1618.
Pearce, J. A. and Norry, M. J., 1979- Petrogenetic implications of Ti, Zr, Y, and Nb variations in volcanic rocks. Contributions to Mineralogy and Petrology 69: 33-47.
Rahgoshay, M. and Shafaii Moghadam H., 2005- Stratiform chromitites in the faryab ophiolitic massif, Southern Iran. Ofioliti, 30(2):85-89.
Rajabzadeh, M. A., 1998- Minéralisation en chrome et éléments du groupe du platine dans les ophiolites d'Assemion et de Neyriz, ceinture du Zagros, Iran. Thèse d'Etat, Institut National Polytechnique de Lorraine, 358pp.
Saccani, E., Delavari, M., Beccaluva, L. and Amini, S., 2010- Petrological and geochemical constraints on the origin of the Nehbandan ophiolitic complex (eastern Iran) : Implication for the evolution of the Sistan Ocean . Lithos 117: 209-228.
Sharma, M. and Wasserburg, G. J., 1996- The neodymium isotopic compositions and rare earth patterns in highly depleted ultramafic rocks. Geochimica et Cosmochimica Acta 60: 4537-4550.
Sigurdsson, H. and Schilling, J. G., 1976- Spinels in Mid-Atlantic ridge basalts: chemistry and occurrence. Earth and Planetary Science Letters 29: 2-7.
Mondal, S., Ripley, E. M., Chusi, L. and Frei R., 2006- The genesis of Archaean chromitites from the Nuasahi and Sukinda massif in the Singhbhym craton, India. Precambrian Research 147: 45-66.
Sun, S. S. and Mc Donough, W. F., 1989- Chemical and isotopic systematic of oceanic basalts: implication for mantle composition and processes, In: Sandres, A.D. and Norry, M.H (Eds), Magmatism in the Ocean Basins. The Geological Society of London 42: 313-345.
Workman, R. K. and Hart, S. R., 2005 Major and trace element composition of the 5 depleted MORB mantle (DMM). Earth and Planetary Science Letters 231(1-2): 53-72.
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