Geodynamic Significance of Cr-spinels from Ophiolite Mantle Peridotites of Northwestern Himalaya
In this contribution the composition of Cr-spinels from Suru valley ophiolite peridotites is described and compared these with published data from Shergol serpentinized peridotites, both of these sequences occur as dismembered ophiolite blocks along the Indus suture zone (ISZ), Ladakh Himalaya and those from Manipur ophiolite belong to the eastern Himalaya. Back scattered electron images reveal that the Cr-spinel have overgrowth of magnetite, which is the dominant textural feature of the investigated rock types. However, in few peridotite samples, gradual replacement of Cr-spinel by ferrian-chromite along grain boundaries commonly occurs. Based on the spinel geochemistry, the Shergol peridotites are characterized by Cr-poor/Al-rich Cr-spinels whereas, the Suru valley peridotites by Cr-rich/Al-poor Cr-spinels. Shergol and Manipur ophiolite indicate their ocean floor affinity and the Suru valley peridotites depict supra subduction zone characteristics.
Unable to display preview. Download preview PDF.
The first author is grateful to the Council of Scientific and Industrial Research (CSIR), New Delhi (India) for providing financial support under CSIR-fellowship sanction no. 09/251(0057)/2014-EMR-I. The authors like to thank Prof. N. V. Chalapathi Rao, Banaras Hindu University Varanasi, India for EPMA analysis. Prof. Shakil Ahmad Romshoo, Head, Department of Earth Sciences, University of Kashmir, is thankfully acknowledged for giving permission to publish this work. All the reviewers are acknowledged for their constructive comments.
- Ahmad, T., Tanaka, T., Sachan, H.K., Asahara, Y., Islam, R. and Khanna, P.P. (2008) Geochemical and isotopic constraints on the age and origin of the Nidar Ophiolitic Complex, Ladakh, India: Implications for the Neo-Tethyan subduction along the Indus suture zone. Tectonophysics, v.451, pp.206–224.CrossRefGoogle Scholar
- Allen, J.F., Sack, R.O. and Batiza, R. (1988) Cr-spinels as petrogenetic indicators: MORB-type lavas from the Lamount seamount chain, eastern Pacific. Amer. Mineral., v.73, pp.741–753.Google Scholar
- Bhat, I.M., Ahmad, T. and Subba Rao, D.V. (2017b) Compositional variability of spinel-group minerals from the Shergol serpentinized peridotites along Indus suture zone, Ladakh Himalaya (India): constraints on tectonomagmatic history. Chemie der Erde Geochemistry v.77, pp.587–595.CrossRefGoogle Scholar
- Bhat, I.M., Ahmad, T. and Subba Rao, D.V. (2018) Complex protolith origin of serpentinized peridotites from the Shergol ophiolitic slice north-western Ladakh Himalaya, Jammu and Kashmir, India. Jour. Appld. Geochem., v.20, pp.213–219.Google Scholar
- Buckman, S., Aitchison, J.C., Nutmana, A.P., Bennett, V.C., Saktura, W.M., Walsh, M.J., Kachovich, S. and Hidaka, H. (2018) The Spongtang Massif in Ladakh, NW Himalaya: An Early Cretaceous record of spontaneous, intra-oceanic subduction initiation in the Neotethys. Gondwana Res., v.63, pp.226–249.CrossRefGoogle Scholar
- Frank, W., Gansser, A. and Trommsdorff, V. (1977) Geological observations in the Ladakh area (Himalayas)-a preliminary report: Schweizerische Mineralogische Petrographische Mitteilungen, v.57, pp.89–113.Google Scholar
- Gansser, A. (1980) The significance of the Himalaya suture zone: Tectonophysics, v.62, pp.37–40.Google Scholar
- Hébert, R., Huot, F., Wang, S.C., Liu, Z.F. (2003) Yalung Zangbo ophiolites (Southern Tibet) revisited: geodynamic implications from the mineral record. In: Dilek, Y., Robinson, P.T. (Eds.), Ophiolites in Earth History. Geol. Soc. London Spec. Publ., v.218, pp.165–190.Google Scholar
- Honegger, K., Dietrich, V., Frank, W., Gansser, A., Thoni, M. and Trommsdorf, V. 1982. Magmatic and metamorphism in the Ladakh Himalayas (the Indus-Tsangpo suture zone): Earth Planet. Sci. Lett., v.60, pp. 253–292.Google Scholar
- Ishii, T., Robinson, P. T., Mackawa, H. and Fiske, R. (1992) Petrological studies of peridotites from diapiric serpentinite seamounts in the Izu-Ogazawara-Mariana fore-arc, LEG 125. Proceedings of Ocean Drilling Program, Scientific Results, no.125, pp.445–485.Google Scholar
- Robertson, A.H.F. (2000) Formation of mélanges in the Indus Suture Zone, Ladakh Himalaya by successive subduction-related, collisional and post-collisional processes during Late Mesozoic-Late Tertiary time. In: Khan, M.A., Treolar, P.J., Searle, M.P., Jan, Q. (Eds.), Tectonics of the Nanga Parbat Syntaxes and the Western Himalaya. Geol. Soc. London, Spec. Publ., v.170, pp.333–374.Google Scholar
- Sachan, H.K. (2001) Supra-subduction origin of the Nidar Ophiolitic sequence, Indus Suture Zone, Ladakh, India: evidence from mineral chemistry of upper mantle rocks. Offioliti, v.26, pp.23–32.Google Scholar
- Singh, A.K. (2009) High-Al chromian spinel in peridotites of Manipur Ophiolite Complex, Indo-Myanmar Orogenic Belt: implication for petrogenesis and geotectonic setting. Curr. Sci., v.96, pp.973–978.Google Scholar
- Sinha, A.K., Mishra, M. (1992) Emplacement of the ophiolitic melange along continental collision zone of Indus Suture Zone in Ladakh Himalaya. Jour. Himalayan Geol., v.3, pp.179–189.Google Scholar
- Sinha, A.K., Mishra, M., 1994. The existence of oceanic islands in the Neotethys: Evidence from Ladakh Himalaya, India. Curr. Sci., v.67, pp.721–727.Google Scholar
- Xiong, F., Yang, J., Ba, D.Z., Liu, Z., Xu, X.Z., Feng, G., Niu, X., and Xu, J. (2014) Different type of chromitite and genetic model from Luobusa ophiolite. Tibet. Acta Petrologica Sinica, v.30, pp.2137–2163.Google Scholar