Bimodal stable isotope signatures of Zildat Ophiolitic Mélange, Indus Suture Zone, Himalaya: implications for emplacement of an ophiolitic mélange in a convergent setup

摘要: Zildat Ophiolitic Melange (ZOM) of the Indus Suture Zone, Himalaya, represents tectonic blocks fragmented oceanic metasediments and ophiolite remnants. The ZOM is sandwiched between fault adjacent to a gneissic dome known as Tso Morari Crystalline (TMC) thin sliver an called Nidar Complex. contain chaotic low-density lithologies metamorphosed sediments hydrated mantle rocks, in which carbonates are present mega-clasts ranging from 100 meters few centimeters size. In this work, calcite microstructures, fluid inclusion petrography stable isotope analyses were carried out envisage emplacement history ZOM. Calcite microstructure varies with decreasing temperature increasing intensity deformation. Intense shearing seen at marginal part melange near fault. These observations consistent tectonically dismembered block, formed plate boundary convergent setup. δ18O δ13C values show bimodal nature deeper (interior) shallower (marginal, fault) melange. Carbonate reflect marine isotopic signature limited fluid–rock interaction, later on provide mixing zone and/or ultramafic rocks. Carbonates depths dominance syn-deformation hydrous fluids, has been modified by metamorphism TMC gneisses. Above reveal that was emplaced over subducting Indian synchronously deformed dome.