Clues to Earth's Past Unit Review (Pt.2)

Periods are subdivided into ____________________, tens of millions of years in duration. Currently, we are in the Holocene, which began about 10,000 years ago.

________________________are the longest units of geologic time. Geologic time is divided into four large segments : Hadean, Archean, Proterozoic, and Phanerozoic. These units of measurement usually last around a billion years.

Another principle of relative-age dating is that sediments are deposited in large, flat sheets. The sheets, or layers, continue in all lateral directions until they thin out or until they meet a barrier, such as the Grand Canyon.

According to the_____________________________________________________, if one rock contains pieces of another rock, the rock containing the pieces is younger than the pieces.

Matching rocks and fossils from separate locations is called ________________________________.

In a(n)________________________________________, younger sedimentary layers are deposited on top of older, horizontal sedimentary layers that have been eroded.

According to the________________________, if one geologic feature cuts across another feature, the feature that it cuts across is older.

A __________________________________________________is the extinction of many species on Earth within a short period of time.

Match it! Select the correct answer from the pull down...Good luck!