Chapter 9 Lesson 2 Practice Questions

A geologist who needed to correlate two rock formations in different areas could match exposed rock layers.

True

According to the principle of superposition, the youngest rock layers are closest to the surface.

True

An unconformity between two sedimentary layers is classified as a disconformity.

True

Index fossils are the remains of species that existed on Earth for relatively short periods of time.

True

Nonconformities occur when sedimentary rocks are deposited on top of uplifted and eroded metamorphic or igneous rocks.

True

To be a useful index fossil, a species must have been rare.

False

With ___________________ dating, a rock's exact age can be determined, whereas with ______________________ dating, a rock's age is compared to the ages of other rocks.

absolute, relative

The gap in the rock record that occurs between folded or uplifted rock layers and a sedimentary rock layer on top of them is called a(n) _____________________________.

angular conformity

The oldest rock layer in an undisturbed rock sequence occurs ______________________.

at the bottom of the sequence

Rock Layers are correlated if they both contain the same __________________.

fossils

The time it takes for half of the atoms in an isotope to decay.

half-life

Index fossils are useful to geologists if the fossils ________________.

have lived over a short period of time

Fossils of species that live on earth for short periods of time and were abundant and widespread geographically.

index fossils

An unconformity is a _____________________ of a rock.

missing layer

What classification of unconformity occurs when sedimentary rock overlies igneous rock?

nonconformity

A process that uses the properties of atoms in rocks and other objects to find their ages.

radioactive decay

Determining the order of events and the relative age of rocks by examining the position of rocks in a sequence is called________________________?

relative dating

The order of events and the relative age of rocks is determined by examining the position of rocks in a sequence.

relative dating

The principle of _______________________ states that, in an undisturbed sequence, the oldest rocks are at the bottom of the sequence and successive layers are younger than those below them.

superposition

The principle of superposition can be used to determine _______________________________.

the relative age of most rock layers

Gaps in rock layers are called ____________________.

unconformities

When part of the rock record is destroyed, the erosional gap that forms is a(n) _____________________.

unconformity