Index Fossils

Front

What are index fossils?

Back

Index fossils are fossils of organisms that were widespread, existed for a short period of geological time, and are used to identify and date the rock layers in which they are found.

Front

What are the two main traits of the best index fossils?

Back

The best index fossils are widespread geographically and have a short lifespan.

Front

Why is fossil #4 not a good index fossil?

Back

Fossil #4 is not a good index fossil because it is not short-lived and is not found in numerous layers.

Front

Which type of organism is often considered a good index fossil?

Back

Organisms that lived for a short time and were widespread, such as trilobites or certain fish.

Front

What is a key characteristic of a good index fossil?

Back

A good index fossil must be found over a wide area of the Earth and be unique.

Front

What is an incorrect statement about index fossils?

Back

An incorrect statement is that the fossil must only be found in one area.

Front

Give an example of a good index fossil.

Back

An example of a good index fossil is the trilobite.

Front

What is the significance of index fossils in geology?

Back

Index fossils help geologists correlate the age of rock layers and understand the geological history of an area.

Front

How do index fossils assist in dating rock layers?

Back

Index fossils assist in dating rock layers by providing a reference point for the age of the layers based on the known time range of the organism.

Front

What is the role of geographic distribution in identifying index fossils?

Back

Geographic distribution is important because index fossils must be found in many different locations to be useful for correlation.