What is "hadean"

a. 1 Pertaining to Hades or hell. 2 (context geology English) Of, or relating to the geologic eon from about 4,600 to 3,800 million years ago; marked by the formation of the solar system, a stable Earth-Moon orbit and the first rocks. n. (context geology English) The eon before 4,000 Ma.

The Hadean is a geologic eon of the Earth, and lies before the Archean. It began with the formation of the Earth about 4.6 billion years ago and ended, as defined by the ICS, 4 billion years ago. The name "Hadean" comes from Hades, the ancient Greek god of the underworld, in reference to the hellish conditions on Earth at the time: the planet had just formed and was still very hot due to high volcanism, a partially molten surface and frequent collisions with other Solar System bodies. The geologist Preston Cloud coined the term in 1972, originally to label the period before the earliest-known rocks on Earth. W. Brian Harland later coined an almost synonymous term: the "Priscoan period". Other, older texts simply refer to the eon as the Pre-Archean. Nonetheless, in 2015, traces of carbon minerals interpreted as "remains of biotic life" were found in 4.1 billion-year-old rocks in Western Australia.