Towards better understanding of geodynamic evolution of the Himalayan orogeny including climatic perturbations and weathering patterns, using petrological (metamorphism, kinetics, deformation and P-T-t estimates) and geochemical (elementary chemistry, geochronology and isotopic fingerprints) tools.
|Petrological and Geochemical Studies in Himalayan Context|
One of the challenging problems of the Himalaya is to trace the magmatic and metamorphic history that can explain the collision tectonics and develop crustal evolution models of the Himalayan orogenic belt. The Himalayan orogen consist of typical representatives of suture zones magmatism and metamorphism that were evolved in subduction-related processes. In the course of defining Himalayan evolution, it is vital to understand arc magmatism, in this regard, the study of petrogenesis of the I-type trans-Himalayan granite plutons and the Karakoram belt of granitoids comprising pre collision older calc-alkaline phase and younger post suture peraluminous leucogranite is important. It is also imperative to study the magmatism represented by volcanics and ultramafic bodies, which are possibly the remnants of the obducted oceanic crust and/or mantle. The tiny remnants of the melt phase and the magmatic fluid is valuable to understand evolution of magma. Further, the Proterozoic crust wherever present in the Himalayan regions is enormously complex because of the several stages of geological processes operated upon it, especially the continent-continent collision between India and Eurasia during Cenozoic deformed and remobilized the Proterozoic Indian crust. Our understanding for such terrain such as in Lesser Himalaya is barely insufficient resulting in the main world wide attraction for their study.
The Himalayan mountain belt also consists of different types of rocks that are metamorphosed up to different grades. For example, the Central Himalayan rocks were deformed at high temperature-pressure conditions a few kilometers beneath the surface of the earth, in ductile or brittle-ductile regime. The association of blueschists, and the UHP metamorphics of the Tso-Morari crystalline in the suture zone support an obduction related evolution of the metamorphic sequences, however, they are required to be defined more clearly in terms of their pseudosection and evolution. The Lesser and the Higher Himalaya together also present metamorphism of the Precambrian suits including fascinating inverted metamorphic sequence. The metamorphism at increased PT to exhumation of these belts needs understanding of the evolution of metamorphogenic fluids at various stages. Since various kind mineralizations of metallic and industrial minerals are either associated with the magmatic/metamorphic rocks or are modified by the circulating fluid system, it is also crucial to study these economically useful mineral not only for their genetic understanding but also to for their social-economic relevance.