This week I decided to travel to the Himalayan Mountains. This huge mountain range began forming around 40-50 million years ago when India and Eurasia landmasses collided because of plate movement.
Both landmasses have equal rock density and when the two collided, instead of descending along with the plate, India's relatively light sedimentary and metamorphic rock pushed against Eurasia plate. The intense pressure could only be relieved pushing upward and contorting the collision zone (which created the very jagged peaks of the Himalayan). There are brittle deformation microstructures within fractured rocks, fault gouge, and non-plunging folds found in the hanging wall. This information tells me that the deformation processes happened in the fault zone close to the surface. The Himalayans are compressive. The kinds of rocks being deposited are sedimentary rocks that at one point laid on the ocean floor. The types of rocks include marl, dolomite, greywacke, siltstone, shale, and limestone. You can also find igneous and metamorphic rocks such as quartzite, metamorphosed sandstone, shale and limestone, slate, marble, granite, diorite, gabbro, tonalite, monazite, pegmatite. Folding dominates the structural style and the fault is a reverse fault.
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