Question

Why are sedimentary rocks the only rock type to contain fossils?

Answer 1

Types of rocks and their formation:

1. There are three types of rocks, that is, Igneous rocks, metamorphic rocks and sedimentary rocks.
2. Igneous rocks are formed deep within the crust from hot magma or lava. Magma and lava cannot contain any living organisms because they originate from the deepest and hottest parts of the Earth, where life is impossible.
3. Metamorphic rocks are formed from igneous or sedimentary rocks under high temperature and pressure which can alter the structure or texture of rocks, making these rocks as devoid of fossils.
4. Depositions of rocks form sedimentary rocks under low temperature and pressure in the ocean and over the Earth's crust. Plants and animals die and fall into a sedimentary deposit.

Reason for sedimentary rocks to be the only rock type to contain fossils:

1. The dead plants and animals, where they are buried by more sediment results in the accumulation of minerals from water in bones which leads to formation of fossils.
2. This makes sedimentary rocks the only rock type to contain fossils.