Miscellaneous Study Materials 16 Nov 2019

Continental Drift & Plate Tectonics

Evidence of Continental Drift: Wegener’s Continental Drift Hypothesis
The Lithosphere is always in a state of work in progress. In 1912, a German geologist named Alfred Wegener came up with an outlandish theory known as continental drift. Download Attachment

Rocks & Minerals Types of Rocks

The three types of Rocks are Sedimentary, Igneous and Metamorphic.
• Igneous rocks
These rocks have crystallized from magma which is made up of various components of pre-existing rocks and has been subjected to melting either at subduction zones or within the Earth’s mantle.
• Sedimentary rocks
These rocks are formed through the gradual accumulation of sediment, such as sand on a beach or mud on a river bed. The sediment is buried and then it is compacted as more and more material is deposited on top. In several thousand to Lakhs of years , the sediment becomes so dense that it becomes a rock. This process is known as lithification.
• Metamorphic rocks
These rocks once existed as igneous or sedimentary rocks but have been subjected to varying degrees of pressure and heat within the Earth’s crust. The processes involved changes the composition and fabric of the rock and their original nature is often hard to distinguish. Metamorphic rocks are typically found in areas of mountain building.
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Relief Features of Land

The entire Earth has been divided into several Geological Provinces on the basis of their origin. A geologic or geomorphic province is an entity with common geologic or geomorphic attributes. The Geological provinces include Continental Shield, Platform-which is a shield covered with sediment, Orogen-which leads to development of mountains, Structural Basins-which are geological depressions, and are the inverse of domes, Large igneous provinces-which are extremely large (More than 100,000 Km2) accumulation of igneous rocks—intrusive, extrusive, or both—in the earth’s crust One example of large igneous province is India’s Deccan trap. The last such geological province is extended crust.
Continental Shields
The first order of relief contains Earth’s continents and ocean basin, which were created by the movements Download Attachment