How is relative age dating like a hamper of clothes?

Relative-age Dating Geologists can learn about the past by studying the present rocks. Relative age dating provides geologists with a method to study the order in which geologic events occurred. This does NOT determine exactly when events occurred, but provides a clearer understanding of events in Earth’s history.

Relative-age Dating Principles Principle of superposition: in a sequence of undeformed sedimentary rocks, the oldest beds are on the bottom and the youngest are on the top.

Relative-age Dating Principles Principle of original horizontality: sedimentary layers are horizontal, or nearly so, when originally deposited. Strata that are not horizontal have been deformed by movements of the Earth’s crust.

Relative-age Dating Principles Principle of faunal succession: groups of fossil plants and animals occur in the geologic record in a definite and determinable order. A period of geologic time can be recognized by its respective fossils.

Relative-age Dating Principles Principle of cross-cutting: geologic features, such as faults, and igneous intrusions are younger than the rocks they cut.

Relative-age Dating Principles Principle of inclusions: a rock body that contains inclusions of preexisting rocks is younger that the rocks from which the inclusions came from.

Relative-age Dating Principles Principle of uncomformities: In some rock formations, layers or parts of layers may be missing. This is often due to erosion. Erosion often leaves a new flat surface with some of the original material missing.

Day 2

1. Sequence your rock strata. 2. Label the principles that apply. Agenda 1. Sequence your rock strata. 2. Label the principles that apply. 3. Work on your vocabulary.

Principle of Inclusion Principle of Cross-cutting (intrusion)

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