Mineralogical studies in Razdar ultramafic – mafic complex (South of Kerman province)

Abstract

Razdar ultramafic–mafic complex is located in south of Kerman province and contains ultramafic (dunite with chromitite, lherzolite, wehrlite, websterite and olivine websterite) and mafic (gabbro) rocks. The most important minerals in this complex are olivine, chromospinel, orthopyroxene, clinopyroxene, plagioclase and amphibole. Mineralogical studies indicate that chemical composition of these minerals from lower to upper parts of Razdar complex has distinctive variation. That is, with variation of rocks from ultramafic to mafic, Mg-contents in ferromagnesian minerals decrease and the minerals become more mafic. Comparision of chemical composition of major minerals in Razdar with other ultramafic association in the world reveals that ultramafic part of Razdar complex likely belongs to upper mantle that has been emplaced in present position by major faults.

Keywords


[1] Sabzehei M., Les melange ophiolitiques de la region d`Esfandagheh, these d`etat,Universite scientifique et medicale de Grenoble, France (1974) p. 306.

[2] Deer W.A., Howie R.A., Zussman J., An Introduction to the rock forming minerals, Longman scientific and technical (1965).

[3] Michael P.J., Bonatti E., Peridotite composition from the north Atlantic: regional and tectonic variation and implications for partial melting, Earth and planetary science letters 73 (1985) pp. 91-104.

[4] McDonough W.F., Frey F.A., Rare earth elements in upper mantle rocks, In: B.R. Lipin and G.A. McKay (Eds), Geochemistry and mineralogy of rare earth elements, Rev. in mineralogy, Min. Soc. Am. 21 (1989) pp. 99-145.

[5] Eggings S.M., Rudnick R.L., McDonough W.F., The composition of peridotites and their minerals: a laser ablation ICP-Ms study, Earth and planetary science letters 154 (1998) pp. 53-71.

[6] Elton D., Chemical trends in abyssal peridotites: referalization of depleted suboceanic mantle, J. of geophysical research, 97(B6) (1992) pp. 9015-9025.

[7] Ceuleneer G., Rabinowicz M., Mantle flow and melt migration beneath oceanic ridges: Models derives from observations in ophiolites, In: Mantle flow and melt generation at mid-Ocean ridges, Geophysical monograph, American Geophysical :union: 71 (1992) pp. 123-154.

[8] Kelemen P.B., Reaction between ultramafic rock and fractionating basaltic magma, 1: phase relations, the origin of calc-alkaline magma series and the formation of discordant dunites, Journal of petrology 31(2) (1990) pp. 51-98.

[9] Leak B.E., Nomenclature of amphiboles, Mineralogical magazine 42 (1978) 533-563.

[10] Ahmed A.H., Arai S., Attia A.K., Petrological characteristics of podiform chromitites and associated peridotites of the PanAfrican Proterozoic ophiolite complexes of Egypt, Minerlum deposita 36 (2001) pp. 72-84.

[11] Ceuleneer G., Monnereau M., Amri I., Thermal Structure of a fossil mantle diapir inferred from the distribution of mafic cumulates, Nature 379 (1996) pp. 149-153.

[12] Dick H.J.B., Bullen T., Chromian spinel as a petrogenetic indicator in abyssal and alpine-type peridotites and spatially associated lavas, contrib. Mineral. Petrology 86 (1984) pp. 54-76.

[13] Spier C.A., Filho C.F.F., The chromite deposits of the Bacuri mafic-ultramafic layered complex, Guyana shield, Amapa state, Brazil Economic geology 96 (2001) pp. 817-835.

[14] Proenza J.A., Gervilla F., Melgarejo J.C., Vera O., Alfonso P., Fallick A., Genesis of sulfide-rich chromite ores by the interaction between chromitite and pegmatitic olivine-norite dikes in the Potosi Mine (Moa-Baracoa ophiolitic massif eastern Cuba), Minerallum deposita 36 (2001) pp. 568-669.

[15] Elton D., stewart M., Ross D.K., Compositional trends of minerals in oceanic cumulates, J. of geophysical research. 97(Bll) (1992) pp. 15189-15199.

[16] Klein C., Hurlbut C.S., Manual of mineralogy, John Wiley and Sons, (1985) p. 596.