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Relative Age. The age of a rock unit or event __________ to the age of another rock unit or event. In other words which layer or event came __________, __________, __________… Ex. Mr. Jensen is older than you are or the sandstone was deposited before the fault occurred. Absolute Age.
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Relative Age • The age of a rock unit or event __________ to the age of another rock unit or event. • In other words which layer or event came __________, __________, __________… • Ex. Mr. Jensen is older than you are orthe sandstone was deposited before the fault occurred
Absolute Age • An actual year or a range of years (sometimes expressed as a __________ __________) • Can be determined with ____________ dating • Can be determined with the use of ________ __________ and __________ __________ __________
Index Fossils • Index fossils (like fads) can help us determine the __________ __________ __________ that the rock formed • The best index fossils are those that lived for a relatively _________ period of time and over a __________ area.
Volcanic Time Markers • Volcanic ash is sent into the __________ _______________ and is carried all over the Earth • __________ of volcanic ash are created all over the Earth. • They can be linked to the __________ and __________
Not every Fossil is an Index Fossil • Some fossils are not useful for determining the age of a rock because they … • Lived for _____ ________ a period of time • Too __________ of an area