Geologic Time Geologic Time l l Relative dating

Geologic Time

Geologic Time l l Relative dating by superposition, cross-cutting relationships, fossils and evolution Absolute dating by radioactive decay (igneous)

Relative Time: The Law of Superposition

Cretaceous Ammonites Ordovician Brachiopods Cambrian Trilobite Devonian Fish

Relative Time: Correlating Strata

Relative Time: Correlating Strata

Relative Time: Correlating Strata

Relative Time: Correlating Strata

Relative Time: Constructing the Geologic Timescale

The greater the variety of fossils the more precise the time determination

Absolute Time

Absolute Time

Absolute Time

Absolute Time

Sequence of Events

Timing of Intrusion

Sequence of Events

Unconformities: Disconformity

Unconformities: Disconformity

Unconformities: Disconformity

Unconformities: Disconformity

Unconformities: Angular Unconformity

Unconformities: Angular Unconformity

Unconformities: Angular Unconformity

Unconformities: Angular Unconformity

Unconformities: Angular Unconformity

Unconformities: Non-conformity

Unconformities: Non-conformity

Unconformities: Non-conformity

Unconformities: Non-conformity

Geologic Time

The Grand Canyon and the Great Unconformity

Sequence of Events

Sequence of Events

Geologic Time l Sequence of Events by superposition, crosscutting relationships, fossils and evolution

Sequence of Events

Sedimentary Facies: Time vs. stratigraphic units