Nature and evolution of mantle section in the Nidar Ophiolite Suite Ladakh India

Abstract

The thesis also reports rare natural evidences of highly reducing environment in newlineand around mantle transition zone. The very high pressure lherzolites bear dense newlineprimary hydrocarbon fluid inclusions along with unusual inclusions of carbons newlineand and#945; Fe2O3 in olivine. newlineThe signatures of serpentine dehydration and formation of garnet bearing newlineserpentinite infer deep and steep subduction of primary oceanic lithosphere newlinewhich releases free high volume of water in sub arc depth. This phenomena newlinefacilitate melting at the overlying mantle wedge and potential of volcanism in newlineintra oceanic arc. Additionally due to dehydration and ascent of magma a newlinesudden vacuum can be formed in mantle wedge which may trigger upwelling newlinefrom mantle transition depth (410 660 km). Thus subduction induced mantle newlineflow may create the geodynamo which initiated the Himalaya building newlineprocess. newlineBesides all, present work documents first site of natural CO2 sequestration in newlineHimalaya. The dunites and serpentinites in Nidar valley react with CO2 at low newlinetemperature to produces magnesite as patches on skin and as veins. newlineUnderstanding the carbonation process is important in terms of global carbon newlinecycle, weathering and fluid rock interaction during serpentinization. newline