define rocks explain classification of rocks
Answers
AnsweDefinition of rock is given up
The lithosphere or the earth's crust is made up of various types of rocks. They differ from one another in texture, structure, colour, permeability, mode of occurrence and degree of resistance due to denudation. Rocks form the basis of soil and determine the type of natural vegetation.
Generally the rocks are classified into three major groups. They are igneous, sedimentary and metamorphic.
Igneous Rocks: The igneous rocks are formed by the cooling and solidification of molten rock or magma. They are subdivided on the basis of origin. Plutonic rocks are igneous rocks formed at some depth in the earth's crust. Eg: Granite, diorite and gabbro. Another type of igneous rocks are Volcanic rocks, they are molten rocks poured out of volcanoes as lavas.
Sedimentary Rocks: They are formed from the sediment accumulated over long periods in the form of fossils of animals,plants and other microorganisms. Based on the origin they are classified into three types. They are mechanically formed sedimentary rocks, organically formed sedimentary rocks and chemically formed sedimentary rocks.
Metamorphic Rocks: All the rocks whether igneous or sedimentary become metamorphic. These rocks are formed under great heat and pressure.