Geologic Time Vocabulary

absolute age

• The actual age in years of an event or object
• A record of the geologic events and life forms in Earth's history.
• the remains or traces of ancient living things

geologists

• Scientists who study Earth and the processes that have shaped Earth over time
• a rock or sediment layer that serves as a time marker in the rock record and results from volcanic ash or meteorite-impact debris that spread out and covered large areas of Earth
• the age of rocks and geologic features compared with other rocks and features nearby

Tags

NGSS.MS-ESS1-4

NGSS.MS-ESS2-2

NGSS.MS-ESS2-3

relative age

• the age of rocks and geologic features compared with other rocks and features nearby
• Distinctive fossil used to compare the relative ages of fossils. They were on the Earth for a short period of time.
• The actual age in years of an event or object

Tags

NGSS.MS-ESS1-4

superposition

• a principle that states that younger rocks lie above older rocks if the layers have not been disturbed
• Gaps in rock sequences
• Scientists who study Earth and the processes that have shaped Earth over time

Tags

NGSS.MS-ESS1-4

original horizontality

• Principle stating that sedimentary rocks are deposited in horizontal or nearly horizontal layers.
• geologic processes that occur today are similar to those that have occurred in the past
• Principle that states that sediments are deposited in large, continuous sheets in all lateral directions.

Lateral Continuity

• Principle that states that sediments are deposited in large, continuous sheets in all lateral directions.
• If one rock contains pieces of another rock, the rock containing the pieces is younger than the pieces.
• Principle stating that sedimentary rocks are deposited in horizontal or nearly horizontal layers.

Tags

NGSS.MS-ESS2-3

inclusions

• If one rock contains pieces of another rock, the rock containing the pieces is younger than the pieces.
• matching rocks and fossils from separate locations
• Principle stating that if one geologic feature cuts across another feature, the feature that it cuts across is older.

Tags

NGSS.MS-ESS1-4

cross-cutting relationships

• Principle stating that if one geologic feature cuts across another feature, the feature that it cuts across is older.

• Principle stating that younger rocks lie above older rocks.

• matching rocks and fossils from separate locations

Tags

NGSS.MS-ESS1-4

fossils

• the remains or traces of ancient living things
• Principle stating that sedimentary rocks are deposited in horizontal or nearly horizontal layers.
• If one rock contains pieces of another rock, the rock containing the pieces is younger than the pieces.

Tags

NGSS.MS-ESS2-3

NGSS.MS-LS4-1

NGSS.MS-LS4-2

mass extinctions

• times when many species on Earth died or became extinct within a relatively short period of time
• Principle that states that sediments are deposited in large, continuous sheets in all lateral directions.
• geologic processes that occur today are similar to those that have occurred in the past

Tags

NGSS.MS-LS4-1