Earth History Vocab 2

Front

Plate Tectonics

Back

Folding and faulting of the earth's crust.

Front

Continental Drift

Back

Gradual movement of continents across Earth's surface over geological time.

Front

Sea-floor spreading

Back

Formation of new oceanic crust via magma upwelling at mid-ocean ridges and outward movement.

Front

Unconformity

Back

Gaps in the geologic record indicating crustal deformation, erosion, and sea level changes.

Front

Index Fossil

Back

Fossil remains of an organism that lived globally for a short time; used to date rock layers.

Front

Absolute Dating

Back

Method to determine the numeric age of a fossil using radioactive decay.

Front

Extinct

Back

A species that once lived on Earth but no longer exists.

Front

Radioactive Decay

Back

spontaneous disintegration of an unstable atom’s nucleus

Front

Half-Life

Back

Time for half of radioactive atoms to decay.

Front

Ice Core

Back

A cylinder from ice sheets revealing Earth's atmospheric history via trapped gases.