Mention the nature of geology and topography of Himalayas & peninsular plateau and the northern plains
Answers
Answer:
Geology of Himalayas - Himalayas are made up of sedimentary rocks which were uplifted because of thrusting of Indian plate into the Eurasian plate. The remnants of erstwhile Tethys sea are supposed to have been crushed between both the plates and uplifted. As both the plates were continental in nature, there was no subsidence and hence no volcanic activity is present in Himalayas although because of initial subsidence of Tethys sea, some volcanic rocks can be found in the Karakarom range in the vicinity of Himalayas. The himalayas are young fold mountains who are still rising at the rate of 5mm per year and this is why earthquakes are fairly common here.
Topography - As Himalayas are fold mountains, anticlines and synclines are present. The rivers in their young stages have crafted V shaped valleys and even gorges at various places. The glaciers have carved out cirques in mountains. Thus, at topographical level, Himalayas have very high absolute and relative relief.
Geology of Peninsular Plateau - It is one of the oldest rock formations on earth going back to nearly 4 billion years ago. It is formed up of granites and gneisses. It is a stable continental block with limited tectonic activity ever since it was separated from Pangea supercontinent. Isolated events like creation of Deccan Lava Traps because of Reunion hotspot and rifting in Narmada and Son valleys break the prolonged tectonic monotony of the peninsular geological history.
Topography - Peninsular plateau has a rugged and undulating relief with scattered hills. Its sides form enscarpments like Western Ghats. Overall, the relief is low. The hard rocks ensure that rivers dont get to form meanders but waterfalls are plenty.
Explanation:
Answer:
During the Upper Cretaceous, about 70 million years ago, the north-moving Indo-Australian Plate (which has subsequently broken into the Indian Plate and the Australian Plate was moving at about 15 cm (5.9 in) per year. About 50 million years ago this fast-moving Indo-Australian Plate had completely closed the Tethys Ocean, the existence of which has been determined by sedimentary rocks settled on the ocean floor and the volcanoes that fringed its edges. Since both plates were composed of low density continental crust, they were thrust faulted and folded into mountain ranges rather than subducting into the mantle along an oceanic trench. An often-cited fact used to illustrate this process is that the summit of Mount Everest is made of marine limestone from this ancient ocean.
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