Cr-spinel Mineral Chemistry from Sawlava Ophiolite Complex, Kurdistan, NW Iran, Geotectonic Setting Implication

Bahman Rahimzadeh , Fariborz Masoudi , Amir Ali Tabbakh Shabani
Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran.
Faculty of Earth Sciences, Kharazmi University, Tehran, Iran.


Ophiolitic ultramafic rocks associated with chromitite lenses are studied in
detail from Sawlava ophiolitic complex along the Zagros suture in the northwest of Iran.
Except one small window in Miana village almost all primary silicates in dunites and
wehrlites have been altered to serpentine; however, Cr-spinel is the surviving phase left.
Chemistry of the Cr-spinel minerals from small chromitite lenses within the ultramafic
units provides information about the primary petrological characteristics. The Cr# of the
Cr-spinels is between 0.76 to 0.82 in chromitite lenses, 0.58 to 0.67 in dunite and 0.49 to
0.52 in wehrlite. Al2O3 values and FeO/MgO ratio in the chromitite lenses indicate a
boninitic melt for the source magmas of the Cr-spinels. The low values of Ti and high
contents of Al and high Cr# in peridotite Cr-spinels reveal a pronounced rate of partial
melting (25-35%) for peridotites. This suggests that Sawlava complex source was mantle
wedge with elevated degrees of partial melting. Olivine, clinopyroxene and Cr-spinel
mineral chemistry shows the characterization similar to those in abyssal to supra-
subduction zone (SSZ) peridotites which suggest a fore-arc basin setting for the
generation of the chromitite lenses from Sawlava ophiolites.

Key Words:
Chromitite, Sawlava
ophiolitic complex,
Zagros, Iran


[1] Irvine T.N. "Cr-spinel as a petrogenetic indicator; Part 2, petrologic applications". Canadian Journal of
Earth Sciences, 4, 71_103. 1967.

[2] Dick H.J.B. and Bullen T. "Chromian spinel as a petrogenetic indicator in abyssal and alpine-type
peridotites and spatially associated lavas". Contributions to Mineralogy and Petrology, 86: 54-76. 1984.

[3] Arai S. "Characterization of spinel peridotites by olivine-spinel compositional relationships: Review and
interpretation". Chemical Geology, 113, 191_204. 1994a.

[4] Barnes S.J. and Roeder P.L. "The range of spinel compositions in terrestrial mafic and ultramafic rocks".
Journal of Petrology, 42, 2279-2302. 2001.

[5] Arai S., Shimizu Y., Ismail S.A. and Ahmad A.H. "Low-T formation of high-Cr spinel with apparently
primary chemical characteristics within podiform chromitite from Rayat, northeastern Iraq". Mineralogical
Magazine, Vol. 70(5), pp. 499–508. 2007.

[6] Barnes S.J. "Chromite in komatiites, II. Modification during greenschist to mid-amphibolite facies
metamorphism". Journal of Petrology, 41, 387-409. 2000.

[7] Ahmed A.H., Arai S. and Attia, A.K. "Petrological characteristics of the Pan African podiform
chromitites and associated peridotites of the Proterozoic ophiolite complexes, Egypt". Mineralium Deposita,
36, 72-84. 2001.

[8] Abzalov M.Z. "Chrome-spinels in gabbro wehrlite intrusions of the Pechenga area, Kola Peninsula,
Russia: emphasis on alteration features". Lithos, 43, 109-134. 1998.

[9] Leblanc M. and Violette J.F. "Distribution of Al-rich and Cr-rich chromite pods in ophiolites". Economic
Geology 78: 293-301. 1983.

[10] Zhou M.F. and Robinson P.T. "High-Cr and high-Al chromitites western China: relationship to partial
melting and melt/rock interaction in the upper mantle". International Geological Reviews 36, 678-686. 1994.

[11] Hock M., Friedrich G., Pluer, W.L. and Wichowski A. "Refractory and metallurgical-type chromite
ores. Zarnbale ophiolite, Luzon, Phillipines". Mineralium Deposita. vol. 21.pp. 190-199. 1986.

[12] Yumul G.P., Jr. and Balce U.K. "Supra-subduction zone ophiolites as favorable hosts for chromitite,
platinum and massive sulfide deposits". Journal of Southeast Asian Earth Sciences, 10, 65-79. 1994.

[13] Lachance G.R. and Trail R.J. "Practical solution to the matrix problem in X-ray analysis". Canadian
Spectroscopy 11: 43-48. 1966.

[14] Pouchou J.L. and Pichoir F. "PAP (pZ) procedure for improved quantitative microanalysis, In: J.T.
Armstrong (Ed.), Microbeam analysis". San Francisco Press, San Francisco, p. 104-106. 1985.

[15] Droop G.T.R. "A general equation for estimating Fe3+ concentrations in ferromagnesian silicates and
oxides from microprobe analyses, using stoichiometric" Contributions to Mineralogy and Petrology, 51: 431-
435. 1987.

[16] Berberian, M. and King G.C.P. "Toward a paleogeography and tectonic evolution of Iran". Canadian
Journal of Earth Science 18: 210–265. 1981.

[17] Agard P., Jolivet L., Vrielynck B., Burov E. and Monié, P., "Plate acceleration: The obduction
trigger?" Earth and Planetary Science Letters 258: 428–441. 2007.

[18] Agard P., Omrani J., Jolivet L. and Mouthereau F. "Convergence history across Zagros (Iran):
constraints from collisional and earlier deformation". Institute Journal of Earth Science (Geol. Rundsch.)
95: 401- 419. 2005.

[19] Ghazi A.M. and Hassanipak A.A. "Geochemistry of sub-alkaline and alkaline extrusive from
Kermanshah Ophiolite, Zagros suture zone, western Iran: implications for Tethyan plate tectonics". Journal
of Asian Earth Science 17 (3): 319-332. 1999.

[20] Nadimi A., "Mantle flow patterns at the Neyriz Paleo – spreading centre, Iran". Earth and Planetary
Science Letters 203: 93-104. 2002.

[21] Sarkarinejad K. "Petrology and tectonic setting of the Neyriz ophiolite, southeast Iran. In: Ishiwatari,
A., Malpas, J. and Ishizuka, H. (Eds.), Circum-Pacific Ophiolites", Proceedings of 29th International
Geological Congress, Part D, 221-234. 2005.

[22] Aswad J.A.Kh., Nabaz Aziz R.H. and Koyi H.A. "Cr-spinel compositions in serpentinites, and their
implications for the petrotectonic history of the Zagros Suture Zone, Kurdistan Region, Iraq". Geological
Magazine. 2011.

[23] Azizi H., Tanaka T., Asahara Y., Chung S. L. and Zarrinkoub M. H. "Discrimination of the age and
tectonic setting for magmatic rocks along the Zagros thrust zone, northwest Iran, using the zircon U–Pb age
and Sr–Nd isotope". Journal of Geodynamics 52: 304– 320. 2011.

[24] Dilek Y. and Furnes H. "Structure and geochemistry of Tethyan ophiolites and their petrogenesis in
subduction rollback systems". Lithos 113: 1-20. 2009

[25] Khalatbari-Jafari M., Juteau T. and Cotton, J. "Petrological and geochemical study of the Late
Cretaceous ophiolites of Khoy (NW Iran), and related geological formations". Journal of Asian Earth
Science 27 (4): 465-502. 2006.

[26] Alavi, M., "Tectonics of the Zagros orogenic belt of Iran; new data and interpretations".
Tectonophysics 229, 211–238. 1994.

[27] Sabzehai M., Gourabjiri A. and Eslamdoust F. "1/100000 Geological map of the Paveh and east of
Paveh". Geological survey of Iran. 2009.

[28] Whitney, D. L. and Evans, B.W. "Abbreviations for names of rock-forming minerals". American
Mineralogist, Volume 95, 185–187. 2010.

[29] Snow, J.E., Dick, H.J.B., Pervasive magnesium loss by marine weathering of peridotite. Geochimica Et
Cosmochimica Acta 59 (20), 4219–4235. 1995.

[30] Casey J. "Comparison of major-and trace-element geochemistry of abyssal peridotites and mafic
plutonic rocks with basalts from the Mark Region of Mid-Atlantic Ridge". Proc. ODP. Sci. Res., 153: 181-
241. 1997.

[31] Ismail S. A., Carr P. F. & Mirza T. "Platinum-group elements geochemistry in podiform chromitites
and associated peridotites of the Mawat ophiolite, northeastern Iraq". Journal of Asian Earth Sciences, 37
(1), 31-41. 2010.

[32] Rollinson H. "The geochemistry of mantle chromitites from the northern part of the Oman ophiolite:
inferred parental melt compositions". Contributions to mineralogy and petrology, 156:273–288. 2008.

[33] McDonough W.F. and Sun S.S. "The composition of the Earth". Chem. Geol., 120: 223-253.

[34] Medaris Jr. G., Wang H., Jelinek E., Mihaljevič M. and Jakeš P. "Characteristics and origins of diverse
Variscan peridotites in the Gfِ hl Nappe, Bohemian Massif, Czech Republic". Lithos, 82: 1-23. 2005.

[35] Proenza J.A., Zaccarini F., Lewis J.F., Longo F. and Garuti G. "Chromian spinel composition and the
platinum-group minerals of the PGE-rich Lomapegvera chromitites, Loma Caribe peridotite". Donimican
Republiccanadian journal of mineralogy, 45: 631-648. 2007.

[36] Robinson P.T., Zhou M.F., Malpas J. and Bai W.J. "Podiform Chromitites: Their composition, origin
and environment of formation". Episodes 20, 247-252. 1997.

[37] Allahyari K., Sacanni E., Pourmoafi M., Beccalova L. and Masoudi, F. "Petrology of mantle peridotites
and intrusive mafic rocks from the Kermanshah ophiolitic complex (Zagros belt, Iran): implication for the
geodynamic evolution of the Neo-Tethyan oceanic branch between Arabia and Iran". Ofioliti 35: 71–90.

[38] Ferrario A. and Garuti G. "Platinum-group mineral inclusions in chromitites of the mafic ultramafic
complex (Ivrea-Zone, Italy)". Mineralogy and Petrology 41:125-143. 1988.

[39] Zaccarini F., Pushkarev E. and Garuti G. "Plutinum-group element mineralogy and geochemistry of
chromitite of the Kluchevskoy ophiolite complex, central Urals (Russia)". Ore geology reviews, 33, 20-30.

[40] Arai S. "Compositional variation of olivine chromian spinel in Mg-rich magmas as a guide to their
residual spinel peridotites". Journal of Volcanology and Geothermal Research, 59, 279_294. 1994b.

[41] Pearce J.A., Barker P.F., Edwards S.J., Parkinson I.J. and Leat P.T. "Geochemistry and tectonic
significance of peridotites from the South Sandwich arc-basin system, South Atlantic". Contributions to
Mineralogy and Petrology 139, 36–53. 2000.

[42] Conrad W.K. and Kay R.W. "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. 1984.

[43] Haggerty S.E., "Upper mantle opaque mineral stratigraphy and the genesis of metasomaties and alkali-
rich melts". J. Geol. Soc. Australia, 14: 687-699. 1988.

[44] Kepezhinskas P.K., Defant M.J. and Drummond M.S. "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. 1995.

[45] Bonavia F.F., Diella V. and Ferrario A. "Precambrian podiform chromitites from Kenticha Hill,
Southern Ethiopia". Econ. Geol., 88: 198-202. 1993.

[46] Augé T. "Chromite deposits in the northern Oman ophiolite: mineralogical constraints". Mineralium
Deposita 22, 1–10. 1987.

[47] Maurel C. and Maurel P. "Tude expérimentale de la solubilité du chrome dans les bains silicatés
basiques et sa distribution entre liquide et minéraux coexistants: conditions d’existence du spinelle
chromifère". Bulletin of Minéralogy, 105: 640-647. 1982.

[48] Ghazi J.M., Moazzen M., Rahghoshay M. and Shafaii Moghadam H. "The geodynamic setting of the
Nain ophiolites, central Iran: evidence from chromian spinels in the chromitites, and associated rocks".
Ofioliti, 36 (1), 59-76 59. 2011.

[49] Ferrario A. and Garuti G. "Platinum-group mineral inclusions in chromitites of the mafic ultramafic
complex (Ivrea-Zone, Italy)". Mineralogy and Petrology 41:125-143. 1988. Hellebrand E., Snow J.E., 
Dick H.J.B. and Hofmann A.W. "Coupled major and trace elements as indicators
of the extent of melting in mid-ocean ridge peridotites". Nature, 410 (6829): 677-681. 2001.

[51] Stowe C.W. "Compositions and tectonic settings of chromite deposits through time". Econ. Geol., 89:
528-546. 1994.

[52] Tamura A. and Arai S. "Harzburgite–dunite–orthopyroxenite suite as a record of supra-subduction
zone setting for the Oman ophiolite mantle". Lithos 90, 43–56. 2006.

[53] Monnier C., Girardeau J., Maury R. and Cotten J. "Back-arc basin origin for the East Sulawesi ophiolite
(eastern Indonesia)". Geology 23, 851–854. 1995.

[54] Kamenetsky V.S., Crawford A.J. and Meffre S. "Factors controlling chemistry of magmatic spinel: an
empirical study of associated olivine, Cr-spinel and melt inclusions from primitive rocks". Journal of
Petrology 42:655–671. 2001.

[55] Pearce J.A., van der Laan S.R., Arculus R.J., Murton B.J., Ishii T., Peate D.W., Parkinson I.J. "Boninite
and harzburgite from LEG 125 (Bonin–Mriana Forearc): a case study of magma genesis during the initial
stages of subduction. In: Fryer, P., Pearce, J.A., Stokking, L.B. (Eds.), Proceedings of the Ocean Drilling
Program, Scientific Results, vol. 125. Ocean Drilling Program". College Station, TX, pp. 623–657. 1992.

[56] Pearce J.A., Barker P.F., Edwards S.J., Parkinson I.J. and Leat P.T. "Geochemistry and tectonic
significance of peridotites from the South Sandwich arc-basin system, South Atlantic". Contributions to
Mineralogy and Petrology 139, 36–53. 2000.

[57] Taylor R.N., Nesbitt R.W., Vidal P., Harmon R.S., Auvray B. and Croudace I.W. "Mineralogy,
chemistry, and genesis of the boninite series volcanics, Chichijima, Bonin Islands, Japan". Journal of
Petrology 35, 577–617. 1994.

[58] Kadoshima K. "Petrological characteristics of the mantle section of the northern Oman and Lizard
ophiolites: an approach from in-situ rocks and detrital chromian spinel". PhD. thesis, [1] Kanazawa
University, Kanazawa. 2002.

[59] Lemee L., Giradeau J. and Monnier C. "Mantle segmentation along the Oman ophiolite fossil midocean
ridge". Nature 432, 167–72. 2004.

[60] Lippard S.J., Shelton A.W. and Gass I.G. "The ophiolite of northern Oman". Geol Soc Mem vol 11.

[61] Takazwa E., Okayasu T. and Satoch K. "Geochemistry and origin of the basal lherzolites from the
northern Oman ophiolite (northern Fizh block)". Geochemistry, Geophysics, Geosystems 4, 1021. 2003.

[62] Shafaii Moghadam H. and Stern R. J. "Geodynamic evolution of Upper Cretaceous Zagros ophiolites:
formation of oceanic lithosphere above a nascent subduction zone". Geological Magazine 148: 762–801.

[63] Delaloye, M., Desmons, J. "Ophiolites and mélange terranes in Iran: a geochronological study and its
paleotectonic implications". Tectonophysics: 68, 83–111. 1980.

[64] Davoudian, A.R., Genser, J., Dachs, E., and Shabanian, N. "Petrology of eclogites from north
of Shahrekord, Sanandaj-Sirjan zone, Iran". Mineralogy and Petrology, March Volume 92, Issue 3-
4, pp 393-413. 2008.