Chapter 14, Problem 10A

Summary Introduction

Introduction:

Different ways contribute to the formation of fossil. Majority of the formation of fossil takes in aquatic environment when an animal or plant dies. The dead carcass then gets buried under the silt and clay. Only the soft tissues of an organism decompose quickly and the hard shells or bones are left behind.

Sediments begin to accumulate over the dead organisms and the remains of the organisms turn in to a rock. When erosion of these rocks takes place, it results in the revealing of these fossil remains.

Answer to Problem 10A

Option (D)

Explanation of Solution

Explanation for correct answer:

Option (D): For a very long period, under certain conditions, sediments get cemented and compacted to form the sedimentary rocks. Even fossils are highly most common in sedimentary rocks, instead of other rocks. Limestones are the most common sedimentary rocks in which majority of the fossils are found. Limestones are made up of shells of organisms. Fossils are also common in shale whose formation is from mud. Hence, the option is correct.

Explanation for incorrect answer:

Option (A): Batholith is intrusive and is relatively younger than other types of rocks. It does not facilitate fossil formation. Hence, the option is incorrect.

Option (B): Igneous rocks do not contain fossil because even if there were any fossil present, the rocks would have melted and later formed into magma. Hence, the option is incorrect.

Option (C): Metamorphic rocks destroy the remains of the fossil and do not provide appropriate pressure and temperature for fossil formation. Hence, the option is incorrect.