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Geology Study of the structure of planet Earth and the forces that make and shape Earth.
Uniformitarianism Geologic processes that operated today also operated in the past.
Igneous Rocks Form when molten material beneath Earth's surface cools and hardens.
Sedimentary Rocks Made of sediments that have been deposited and then pressed together.
Metamorphic Rocks Form when an existing rock is changed by heat, pressure, or chemical reactions.
Rock Cycle A series of processes on and beneath Earth's surface that slowly change rocks from one kind to another.
Magma Molten material beneath Earth's surface.
Lava Magma that flows to the surface.
Relative Age The age of a rock compared to the ages of other rocks.
Absolute Age The number of years since the rock formed.
Law of Superposition In horizontal rock layers, the oldest is at the bottom and the youngest is at the top.
Extrusion Lava that hardens on the surface.
Intrusion Igneous rock formed when magma cools and hardens.
Fault A break in Earth's crust.
Unconformity The surface where new rock layers meet a much older rock surface beneath them.
Inclusion A piece of rock contained in another rock.
Index Fossil A widely distributed organism that existed briefly.
Atom The small particles that make up matter.
Element When all atoms in a particular type of matter are the same.
Radioactive Decay The process in which the atoms of one element break down to form atoms of another element.
Half Life Time it takes for half of the radioactive atoms to decay.
Erosion Process in which natural processes break down rocks and carry away the pieces.
Geologic Time Scale A record of life forms and and geologic events in Earth's history.
Era Three long units between Precambrian and present.
Period Subdivision of era.
Invertebrates Animals without backbones.
Vertebrates Animals with backbones.
Amphibian Animal that lives on land and water.
Reptile Vertebrate with scaly skin and leathery, tough shelled eggs.
Mass Extinction Event in which many different organisms die at the same time.
Mammal Warm blooded vertebrate that feeds its young milk.
Created by: sgust