<Tr> <Td> Basin Groups (Paleohadean) (unofficial) </Td> <Td_colspan="4"> End of the Early Bombardment Phase . Oldest known mineral (Zircon, 4,404 ± 8 Ma). Asteroids and comets bring water to Earth . </Td> <Td> 4533 </Td> </Tr> <Tr> <Td> Cryptic (Eohadean) (unofficial) </Td> <Td_colspan="4"> Formation of Moon (4,533 to 4,527 Ma), probably from giant impact, since the end of this era . Formation of Earth (4,570 to 4,567.17 Ma), Early Bombardment Phase begins . Formation of Sun (4,680 to 4,630 Ma). </Td> <Td> 4600 </Td> </Tr> <P> The ICS's Geologic Time Scale 2012 book which includes the new approved time scale also displays a proposal to substantially revise the Precambrian time scale to reflect important events such as the formation of the Earth or the Great Oxidation Event, among others, while at the same time maintaining most of the previous chronostratigraphic nomenclature for the pertinent time span . (See also Period (geology) #Structure .) </P> <Ul> <Li> Hadean Eon--4600--4031 MYA <Ul> <Li> Chaotian Era--4600--4404 MYA--the name alluding both to the mythological Chaos and the chaotic phase of planet formation </Li> <Li> Jack Hillsian or Zirconian Era--4404--4031 MYA--both names allude to the Jack Hills Greenstone Belt which provided the oldest mineral grains on Earth, zircons </Li> </Ul> </Li> <Li> Archean Eon--4031--2420 MYA <Ul> <Li> Paleoarchean Era--4031--3490 MYA <Ul> <Li> Acastan Period--4031--3810 MYA--named after the Acasta Gneiss </Li> <Li> Isuan Period--3810--3490 MYA--named after the Isua Greenstone Belt </Li> </Ul> </Li> <Li> Mesoarchean Era--3490--2780 MYA <Ul> <Li> Vaalbaran Period--3490--3020 MYA--a portmanteau based on the names of the Kapvaal (Southern Africa) and Pilbara (Western Australia) cratons </Li> <Li> Pongolan Period--3020--2780 MYA--named after the Pongola Supergroup </Li> </Ul> </Li> <Li> Neoarchean Era--2780--2420 MYA <Ul> <Li> Methanian Period--2780--2630 MYA--named for the inferred predominance of methanotrophic prokaryotes </Li> <Li> Siderian Period--2630--2420 MYA--named for the voluminous banded iron formations formed within its duration </Li> </Ul> </Li> </Ul> </Li> <Li> Proterozoic Eon--2420--541 MYA <Ul> <Li> Paleoproterozoic Era--2420--1780 MYA <Ul> <Li> Oxygenian Period--2420--2250 MYA--named for displaying the first evidence for a global oxidizing atmosphere </Li> <Li> Jatulian or Eukaryian Period--2250--2060 MYA--names are respectively for the Lomagundi--Jatuli δ C isotopic excursion event spanning its duration, and for the (proposed) first fossil appearance of eukaryotes </Li> <Li> Columbian Period--2060--1780 MYA--named after the supercontinent Columbia </Li> </Ul> </Li> <Li> Mesoproterozoic Era--1780--850 MYA <Ul> <Li> Rodinian Period--1780--850 MYA--named after the supercontinent Rodinia, stable environment </Li> </Ul> </Li> <Li> Neoproterozoic Era--850--541 MYA <Ul> <Li> Cryogenian Period--850--630 MYA--named for the occurrence of several glaciations </Li> <Li> Ediacaran Period--630--541 MYA </Li> </Ul> </Li> </Ul> </Li> </Ul>

How the earth’s history can be interpreted from the geologic time scale