11.2 Relative Age

Question 1

Formations

Answer 1

Named sets of layers, usually of sediments or sedimentary rocks, which have distinct properties, such as the type of rock or fossils found in the layers.

Question 2

Principle of cross-cutting relationships

Answer 2

The principle which states that features that cut through existing rock layers are always younger than the rocks they cut across.

Question 3

Principle of original horizontality

Answer 3

The principle which states that sedimentary layers are deposited in horizontal or near-horizontal layers.

Question 4

Principle of superposition

Answer 4

The principle which states that in a stack of sedimentary rock layers that have not been severely deformed, the oldest layers are at the bottom, and the youngest layers are at the top.

Question 5

Relative-age dating

Answer 5

The process of determining the order of events in Earth history.

Question 6

Unconformity

Answer 6

An erosional surface preserved in a stack of rock layers. Three types include nonconformity, disconformity, and angular unconformity.