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Geo History

TermDefinition
Eon The largest unit of geologic time, lasting billions of years.
Era A unit of geologic time that lasts hundreds of millions of years and is a subdivision of an eon.
Epoch A unit of geologic time that is a subdivision of a period; usually 13-35 million years long.
Law of Superposition A principle in geology that states that the oldest rock layers are at the bottom of a sequence, and the youngest rock layers are at the top.
Geologic Time Scale A record of the major events and diversity of life forms present in Earth's history.
Periods A division of geologic time that is a subdivision of an era.
Relative Dating The process of determining if one rock or geologic event is older or younger than another, without knowing their specific ages.
Absolute Dating A method used to determine the actual age of a rock, fossil, or geologic event in years, often by using the presence of radioactive minerals.
Fossils The preserved remains or traces of a living organism from the distant past.
Index Fossils A widespread fossil of a plant or animal that lived for a short time and can be used to date the rock layer it's found in.
Examples of Index Fossils Trilobite and Ammonite
Created by: abbasim
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