Fossils and Geologic Time

Of the 5 mass extinctions that scientists believe have occurred, which event was the largest?

• Ordovician-Silurian

• Late Devonian

• Permian-Triassic

• Triassic-Jurassic

What chart is used to place all of the geologic events and life forms in chronological order?

• Geologic Time Scale

• Depth Chart

• Bathymetric Chart

• Family Tree

According to the law of superposition, the oldest fossils are found 

• At the top of the rock layers

• Near the bottom of the rock layers

• In the middle of the rock layers

• Somewhat near the surface

Which type of rock is most likely to contain fossils?

• intrusive igneous rocks

• sedimentary rocks

• metamorphic rocks

• extrusive igneous rocks

These fossils allow geologists to match rocks of the same age in different regions because they were widespread and only around for a short period of time.

• index fossil

• trace fossil

• cryofossil

• varve

What rock layer is the oldest ?

• a

• b

• c

• d

According to this chart, the half-life of Carbon-14 is _______ years.

• 0 years

• 5,700 years

• 11,400 years

• 17,100 years

Evidence best indicates that rock layers 4 and 8 were deposited during the same geologic period because both layers

• contain the same index fossil

• are composed of glacial sediments

• contain index fossils of the same age

• are found in the same area

Which best describes a fossil that helps determine the relative age of a rock layer?

• trace fossil

• index fossil

• radioactive fossil

• unconformity fossil

The index fossil of a type of trilobite is discovered in layer A of a set of rock layers found at three different sites of a field investigation. Which conclusion can be made about the rocks in layer A at all three sites?

• The rocks are all different ages

• The rocks are all about the same age

• The rocks were formed from melting magma

• The rocks were formed during a catastrophic event