Geologic Time

Geologic Time Relative Time/absolute time Eons Eras Period Epoch

Geologic time #Relative Time - time scale based on relationships and order (what happens 1st, 2nd 3rd and so on)) # Absolute time – based on numerical proportions Measurable time days weeks months years centuries millennia

## EONS The largest Unit of Geological time Geologic time has been divided into 4 Eons # Hadean Eon # Archeon Eon # Precambrian Eon ## Phanerozoic Eon We live in the Phanerozoic Eon which dates back from 540 million years ago

#Era A smaller division of an Eon Two or more geological unites comprise an era, which is hundreds of millions of years in duration. We live in the Cenozoic Era ( the era of mammals) it began 65 million years ago

Period The period is the basic unit of geological time in which a single type of rock system is formed, lasting tens of millions of years. Each Era can be broken into two or more periods We live in the Quaternary Period, 1.8 million years

Epoch An epoch is a division of a geologic period; it is the smallest division of geologic time. We live in the Holocene Epoch 11,000 years ago Hadean

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For the test! Explain the differences between absolute and relative time Explain Relative time and how it is broken down (at least two eras make an Eon and two periods form an Era etc.) Recognize two geological eons and what the differences is between the two Recognize the eras within each eon