E. Answer the following questions in detail,
1. How are igneous rocks formed? Why are they also called primary rocks?
2. What are the various types of igneous rocks based on their origin?
3. How are sedimentary rocks formed? How are they classified on the basis of their formation?
4. Differentiate between igneous rocks and sedimentary rocks.
5. How are metamorphic rocks formed? Why are they layered?
6. What is the cyclical relationship that exists between the three rock groups?
7. What are the different uses of the rocks?
Answers
Answer:
Igneous rocks are created from the cooling of molten magma/lava. All other rocks are derived from them. Because they form the basis of formation of other types of rocks, igneous rocks are known as the primary rocks.
Explanation:
Igneous rocks are created from the cooling of molten magma/lava. All other rocks are derived from them. Because they form the basis of formation of other types of rocks, igneous rocks are known as the primary rocks.
The two main categories of igneous rocks are extrusive and intrusive. Extrusive rocks are formed on the surface of the Earth from lava, which is magma that has emerged from underground. Intrusive rocks are formed from magma that cools and solidifies within the crust of the planet
Sedimentary rocks are formed when sediment is deposited out of air, ice, wind, gravity, or water flows carrying the particles in suspension. This sediment is often formed when weathering and erosion break down a rock into loose material in a source area.Sedimentary rocks are classified based on how they form and on the size of the sediments, if they are clastic. Clastic sedimentary rocks are formed from rock fragments, or clasts; chemical sedimentary rocks precipitate from fluids; and biochemical sedimentary rocks form as precipitation from living organisms.
Metamorphic rocks start off as igneous, sedimentary, or other metamorphic rocks. These rocks are changed when heat or pressure alters the existing rock's physical or chemical make up. ... Extreme pressure may also lead to the formation of foliation, or flat layers in rocks that form as the rocks are squeezed by pressure.