| Chaotian | |
| Top Bar: | all time |
| Time Start: | 4568 |
| Time End: | 4404 |
| Subdivisions: | See text |
| Celestial Body: | Earth |
| Usage: | Proposed subdivision of the Hadean eon |
| Chrono Unit: | Era |
| Strat Unit: | Erathem |
| Proposed By: | C., Zahnle, K. J., Sleep, N. H., and Nisbet, E. G., 2010 |
| Lower Boundary Def: | Formation of the Earth |
| Upper Boundary Def: | Collision between Proto-Earth and the Protoplanet Theia |
The Chaotian is a proposed time division of the geologic time scale. First proposed in 2010[1] as an eon, it is named after Chaos, the primeval void in Greek mythology. This proposal defines the Chaotian eon as a Solar System-wide time between the initiation of planetary formation and the hypothesised collision of the trojan dwarf planet Theia with the proto-Earth.
A revised proposal in 2012 suggested the Chaotian as the first era of the Hadean representing the time between the formation of the Solar System c. 4.567 Ga[2] and the oldest preserved crustal material on Earth, a detrital zircon c. 4.404 Ga[3] from the Jack Hills of the Narryer Terrane in Western Australia.
, neither proposal had been adopted or officially ratified by the International Union of Geological Sciences.[4]
The original proposal in 2010 divided the Chaotian into two eras and four periods. No numerical upper age limits were provided, only the younger age limit of ~4.5 Ga for the boundary between the proposed Chaotian and Hadean boundary.
The revised proposal in 2012 did not subdivide the proposed Chaotian era (of the Hadean eon) into periods.
| Chaotian | Neochaotian | Titanomachaen | > ~4.5 |
| Hyperitian | |||
| Eochaotian | Erebrean | ||
| Nephelean |
| Hadean | Jack Hillsian or Zirconian | 4.404 to 4.030 |
| Chaotian | 4.568 to 4.404 |