Describe the “Theory of Plate Tectonics”. …

a. Plate tectonics is the theory that states that Earth's outer shell is divided into several plates that glide over the mantle. The plates act like a hard and rigid shell compared to Earth's mantle. This strong outer layer is called the lithosphere. Plate tectonics is the modern version of continental drift. The plates consist of two principal types of material, oceanic crust, and continental crust. The earth is considered to have 15 major tectonic plates. Seven of which are primary plates and the rest are secondary plates. The primary plates are the African plate, the Antarctic plate, the Eurasian plate, the Indo-Australian plate, the North American plate, the Pacific plate, and the South American plate. The secondary plates are the Arabian plate, the Caribbean plate, the Cocos plate, the Juan de Fuca plate, the Indian plate, the Nazca plate, the Philippine Sea plate and the Scotia plate

According to the Theory of Plate Tectonics, the Earth's crust was initially a single, giant super-continent called Pangea. Its northern part was the Angara land and the southern part was the Gondwana land. The convectional currents split the crust into a number of pieces, thus leading to the drifting of the Indo- Australian plate after being separated from the Gondwana land, towards north. The northward drift resulted in the collision of the plate with the much larger Eurasian Plate.

Due to this collision, the sedimentary rocks which were accumulated in the geosyncline known as theTethys were folded to form the mountain system of western Asia and Himalaya.