Geochemical and Petrological Characterization of Sapi Shergol Ophiolite Western Ladakh Constraints on Petrogenesis and Mineralization

Abstract

newline Present research work addresses the maiden integrated mineral chemistry and wholerock major, trace, rare earth element (REE), platinum group elements (PGE) and Ndisotope geochemistry of the mafic-ultramafic ophiolitic rocks from the Sapi-Shergol newlineand Suru Valley ophiolitic slices, western Ladakh Himalaya in order to evaluate their newlinePGE potential, petrogenesis and geodynamic setting. newlineIn Ladakh Himalaya, ophiolitic rocks are reported as isolated tectonic slabs all newlinealong the Indus Suture Zone (ISZ) from west to east for about 400 km length and newlinerepresent the remnants of Mesozoic Neo-Tethys Ocean. In Kargil district of Ladakh, newlinethe ophiolites are best exposed at Dras Village, in Suru Valley south of Kargil and at newlineShergol Village east of Kargil in the form of Sapi-Shergol ophiolitic melange. The newlineShergol ophiolitic slice is a dismembered ophiolite consisting predominantly of newlineserpentinized peridotites with minor associated Shergol mafic intrusives exposed newlinealong Sapi-Shergol transect. In Suru Valley, another ophiolitic slice is outcropped at newlineTrespone village, 30 km south of Kargil Town, predominantly consisting of newlineserpentinized ultramafic rocks and are stratigraphically overlain by Dras arc complex. newlineOn the basis of modal mineralogy, the Shergol and Suru Valley peridotites were newlineidentified as spinel-bearing harzburgites. The back scattered electron (BSE) images of newlineShergol and Suru Valley ophiolitic peridotites reveal that the Cr-spinel have newlineovergrowth of magnetite and ferritchromite. Based on the spinel geochemistry, the newlineShergol peridotites are characterized by Cr-poor/Al-rich Cr-spinels whereas, the Suru newlineValley peridotites by Cr-rich/Al-poor Cr-spinels. Relative to primitive mantle these newlinerock types have depleted major and rare earth element (REE) geochemical newlinecharacteristics comparable to ocean floor mantle rocks reflecting their mantle residual newlinenature. The characteristic U-shaped chondrite normalized REE-patterns and wholerock heavy-REE concentrations correspond to those of abyssal mantle rocks from newlinemid-.....