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15 Cards in this Set

  • Front
  • Back
Radioactive decay
The breakdown of a radioactive element, releasing particles and energy.
Law of Superposition
The geologic principle that states that in horizontal layers of sedimentary rock, each layer is older than the layer above it and younger than the layer below it.
Cinder Cone
A steep, cone-shaped hill or mountain made of volcanic ash, cinders, and bombs, piled up around a volcano's opening.
Composite volcano
A tall, cone-shaped mountain in which layers of lava alternate with layers of ash and other volcanic materials.
Index Fossils
Fossils of widely distributed organisms that lived during only one short period.
Shield Volcano
A wide, gently sloping mountain made of layers of lava and formed by quiet eruption.
A place where an old, eroded rock surface is in contact with a newer rock layer.
The point on Earth's surface directly above an earthquake's focus.
The point beneath Earth's surface where rock breaks under stress and causes an earthquake.
P wave
A type of seismic wave that compresses and expands the ground.
S wave
A type of seismic wave that moves the ground up and down or side to side.
Surface Wave
A type of seismic wave that forms when P waves and S waves reach Earth's surface.
Absolute Age
The age of a rock given as the number of years since the rock formed.
One of the three long units of geologic time between the Precambrian and the present.
The name of the single landmass that broke apart 225 million years ago and gave rise to today's continents.