Earth Through Time

The actual age of rock or fossil in a unit of time (usually years).

• absolute age

• relative age

• relative dating

• absolute dating

A method of determining whether an event or object is older or younger than other events or objects.

• absolute age

• relative age

• absolute dating

• relative dating

Tags

NGSS.HS-ESS1-5

The age of rocks and fossils compared to the age of other rocks and fossils.

• absolute age

• relative age

• absolute dating

• relative dating

The time required for half of a sample of a radioactive isotope to break down to form a daughter isotope.

• radiometric dating

• index fossil

• absolute time

• half life

Tags

NGSS.HS-PS1-8

This is a timeline used to organized the Earth’s geological history into manageable periods.

• Geologic Time Scale

• Biostratigraphy Column

• Eons

• Epochs

Tags

NGSS.MS-ESS1-4

A fossil that is easily recognizable and looks unique, geographically widespread, and lived for a short time.

• isotope

• unconformity

• index fossil

• half life

The largest division of the geologic time scale.

• epochs

• periods

• eras

• eons

Tags

NGSS.MS-ESS1-4

A method of determining the absolute age of an object by comparing the relative percentages of a radioactive (parent) isotope and a stable (daughter) isotope.

• relative dating

• radiometric dating

• half life

• unconformity

Tags

NGSS.HS-PS1-8

The trace or remains of an organism that lived long ago, usually preserved in sedimentary rock.

• fossil

• rock

• isotope

• index fossil

Tags

NGSS.MS-LS4-1

NGSS.MS-LS4-2

A gap in the sequence of rock layers--occurs where older rock layers eroded away completely before new rock layers were deposited.

• era

• half life

• unconformity

• relative age

Tags

NGSS.MS-ESS1-4