Geological Time Scale

Question 1

Precambrian

Answer 1

Relating to or denoting the earliest eon if the earth’s history, preceding the Cambrian period and the Phanerozoic eon.

Question 2

Cambrian explosion

Answer 2

An event approximately 541 million years ago in the Cambrian period when most major animal phyla appeared in the fossil record. It lasted about 20-25 million years and resulted in the divergence if most modern metazoan phyla

Question 3

Eon

Answer 3

A unit of time equal to a billion years

Question 4

Era

Answer 4

A geological era is a subdivision of geologic tins that divided an eon into smaller units of time.

Question 5

Period

Answer 5

A geological period is one of several subdivisions of geologic time enabling cross referencing of rocks and geologic events from place to place

Question 6

Epoch

Answer 6

A division of time that us a subdivision of a a period and is itself subdivided into ages corresponding to a series I in chrinostratigraphy