Geologic Time Scale Flashcard

Front

Humans evolved in what eon?

Back

Phanerozoic

Front

Earth is thought to be formed ______ years ago?

Back

4.6 billion

Front

What is an eon?

Back

Long span of geologic time. In formal usage, the longest portions of geologic time.

Front

What does Phanerozoic mean?

Back

Visible Life

Front

Proterozoic Started Around What Time?

Back

2500 mya

Front

What is the geologic time scale?

Back

A system of chronological dating that relates geological strata to time.

Front

What are the four eons of the geologic time scale?

Back

Hadean, Archean, Proterozoic, Phanerozoic.

Front

What is the significance of the Hadean eon?

Back

It is the time period when the Earth was formed and the conditions were extremely hot.

Front

What major events occurred during the Archean eon?

Back

Formation of the first stable continental crust and the appearance of the first life forms.

Front

What does the term 'Proterozoic' mean?

Back

Earlier Life.