Hadean

nouns

the earliest eon in the history of the Earth from the first accretion of planetary material (around 4,600 million years ago) until the date of the oldest known rocks (about 3,800 million years ago); no evidence of life
Hadean, Hadean aeon, Hadean eon, Hadean time, Priscoan, Priscoan aeon, Priscoan eon

adjectives

of or relating to or characteristic of Hades or Tartarus
Hadean, Plutonian, Tartarean
is derived from
Hades