Using fossils as guides, they began to piece together a crude history ... its age can be determined. Using this technique, called radiometric dating, scientists are able to "see" back in time.

Precambrian time covers the vast bulk of the Earth's history, starting with the ... Time The Precambrian is the earliest of the geologic ages, which are marked by different layers of sedimentary ...

The official history ... ice age. But the Holocene itself can be subdivided, according to the International Commission on Stratigraphy (ICS). It is the official keeper of geologic time and it ...