Fossil Preservation and Relative Dating

All of the following conditions help preserve organisms as fossils EXCEPT ____.

• quick burial by sediments

• hard parts

• protection from scavengers

• activities of microorganisms

If the same types of fossils are found in two separate rock layers, it's likely that the two rock layers ____.

• formed at different times

• are part of one continuous deposit

• formed under different conditions

• none of the above

Determining the order of events and the relative age of rocks by examining the position of rocks in a sequence is called ____.

• absolute dating

• radiometric dating

• relative dating

• radiocarbon dating

Gaps in rock layers are called ____.

• unconformities

• index fossils

• half-lives

• none of the above

If the same sequence of rock layers is observed over a large area, ____.

• they are probably not related

• a large deposit of rock formed over a large area

• conditions of formation were probably very different

• it is just a coincidence

A limestone bed containing fossils that are 550 million years old is ____ a bed of sandstone containing fossils that are 400 million years old.

• younger than

• the same age as

• older than

• not related to

In a series of undisturbed rock layers where shale lies between sandstone below and limestone above, the ____.

• limestone is youngest

• shale is youngest

• sandstone is youngest

• beds are all the same age

____ dating uses the properties of atoms in rocks and other objects to find their ages.

• Comparative

• Absolute

• Approximate

• Relative

Rock layers are correlated if they both contain the same ____.

• elements

• shapes

• fossils

• type of rock

If a layer of sandstone lies on top of a layer of limestone in which a 300-million-year-old fossil is found, and there are no unconformities, the layer of sandstone must be ____.

• older than 300 million years

• younger than 300 million years

• about 300 million years old

• older than 600 million years