What are measured in eras and periods?

Answer 1

Eras are great lengths of time but periods are the small amounts of time in eras.

Answer 2

Super-Eons, Eons, Eras, Periods, Epochs and Ages are all units of geological time.

Super-Eons are divided into Eons, Eons in Eras, Eras into Epochs and Epochs into Ages.

An example is

The Precambrian Super-Eon (4,500 - 542 Ma) is divided into the

Hadean Eon (4,500 - 3,800 Ma),

Archean Eon (3,800 - 2,500 Ma) &

Proterozoic Eon (2,500 - 542 Ma).

The Proterozoic Eon (2,500 - 542 Ma) is divided into the

Paleoproterozic Era (2,500 - 1,600 Ma),

Mesoproterozic Era (1,600 - 1,000 Ma) &

Neoproterozic Era (1,000 - 542 Ma).

The Neoproterozic Era (1,000 - 542 Ma) is divided into the

Tonian Period(1,000 - 850 Ma),

Cryogenian Period (850 - 630 Ma) &

Ediacaran Period (630 - 542 Ma).

And so on.

Answer 3

Eras and periods are units of geologic time used to categorize Earth's history based on major events or changes in the planet's development. They are typically defined by significant shifts in climate, geological formations, or the appearance and extinction of certain life forms. Examples of eras include the Paleozoic, Mesozoic, and Cenozoic, while periods within these eras include the Jurassic and Cretaceous periods.

Answer 4

Eras and periods both appear at the start of the Cambrian period.

Answer 5

Geologic time scale