Question

Rocks formed by solidification of molten rock materials are

• A. Igneous rocks
• B. Sedimentary rocks
• C. Metamorphic rocks
• D. Stratified rocks

Answer 1

Answer:

A. Igneous rocks

Rocks

• The diversity of rocks (different colours and hardness) is due to its constituents. The constituents of rocks are called minerals.

• Based on the mode of formation, rocks can be classified into 3 - igneous, sedimentary, and metamorphic.

Igneous rocks

• Formed by the molten rock material rising through the fissures in the crust and solidifying. Eg:- granite, basalt.

• As all other rock types are formed from the igneous rocks, they are called primary rocks.

Sedimentary rocks

• Rocks undergo weathering. The debris so formed will be deposited in the low regions as layers and gradually get lithified and transformed into sedimentary rocks. Eg:- sandstone, limestone.

• As the sedimentary rocks are formed in layers, they are also known as stratified rocks.

• The remains of ancient plants and animals found in sedimentary rocks are called fossils. Coal, petroleum, natural gas, etc. Are called fossil fuels.

Metamorphic rocks

• Formed when rocks undergo physical and chemical changes due to high temperature and pressure. Eg:- marble, slate.

• Metamorphic rocks are prominent in Kerala.