Geologic Time: Measuring Earth's History

It states that Earth's processes have always occurred at the same rate and manner as today.

It determines the order of geologic events by examining rock positions.

It provides specific numeric ages for rocks using radioactive decay.

It suggests that Earth's surface never changes.

Superposition

Original Horizontality

Lateral Continuity

Cross-Cutting Relationships

Sedimentary layers extend laterally until they thin out or encounter a barrier.

Sedimentary layers are always deposited vertically.

Sedimentary layers are always the same thickness everywhere.

Sedimentary layers never change direction.

Angular unconformity

Nonconformity

Disconformity

Paraconformity

Lateral Continuity

Cross-Cutting Relationships

Faunal Succession

Superposition

It is not widespread

it is not short-lived (in numerous layers)

It is in half of the outcrops

The Mesozoic Era is known as the age of reptiles and dinosaurs.

The Hadean Eon marks the explosion of complex life.

The Cenozoic Era began before the Paleozoic Era.

The Archean Eon is the most recent era.

First forests appeared

Dinosaurs became abundant

First amphibians evolved

Coal-forming swamps developed

Carbon-14

Uranium-Lead

Potassium-Argon

Lead-210

Relative Dating

Absolute Dating

Uniformitarianism

Comparative Dating