Unconformities
True or false: An unconformity can represent millions of years.
True
Times when many species on Earth died or became extinct within a relatively short period of time.
mass extinction
The principle that if one geologic features cuts across another feature, the feature that it cuts across is older
Cross cutting relationships
In superposition, the oldest rocks are found here.
The bottom
Actual age, numerical age, in years of a rock or an object
Absolute Age
An unconformity is a surface where rock has ____________away, producing a break or a gap in the rock record.
Eroded
The matching of rock layers or fossils exposed in one geographic region to similar layers or fossils exposed in other geographic regions.
Correlation
The principle that in undisturbed rock layers, the oldest rocks are on the bottom
superposition
True or False: In cross cutting relationships, the cut is OLDER than the rock it cuts.
False
The age of rocks and geologic features compared with other nearby rocks and features
Relative Age
Where horizontal layers of sedimentary rock are laid down on top of tilted, eroded layers.
Angular Unconformity
The most useful fossils represent a species that existed on Earth for a short length of time, were abundant, and inhabited many locations.
Index fossils
A piece of an older rock that becomes part of a new rock. The principle states that if one rock contains pieces of another rock, the rock containing the pieces is younger than the pieces.
Inclusion
True or false: Lateral Continuity can be used when correlating rock layers.
True
The preserved remains or evidence of past living organisms.
fossils
When a layer of sedimentary rock overlies a layer of igneous or metamorphic rock that has been eroded.
Nonconformity
A rock or sediment layer with distinctive characteristics that make it easily identifiable in correlation.
Key Bed
A principle that states that sediments are deposited in large, continuous sheets in all lateral directions.
lateral continuity
Geologists organized the Geologic Time Scale based on ____________and_______________.
Rocks and Fossils
The principle that states that geologic processes that occur today are similar to those that have occurred in the past.
Uniformitarianism
When horizontal layers of sedimentary rock overlie another horizontal layer of sedimentary rock that has been eroded.
Disconformity
A model of Earth's history from its origin 4.6 billion years ago to the present.
Geologic Time Scale
The principle that most rock forming materials are deposited in horizontal layers
original horizontality
Which rocks contain fossils of more complex life forms? Younger or older
younger
Which is older, pieces of rock, or the rock they are included in?
The pieces of rock