Archean
Early Earth epoch
Archean refers to a geological eon spanning roughly 4 to 2.5 billion years ago, when Earth's crust solidified and the earliest life emerged.
It follows the Hadean eon and precedes the Proterozoic.
Archean rocks are among the oldest on Earth: Archean granite formations in Western Australia.
Also spelled Archaean.
Metamorphosed rock, often jade
- gneissFoliated metamorphic rock
- graniteIgneous rock, quartz-rich
- basaltFine-grained volcanic stone
- amphiboliteMetamorphosed mafic rock
chert · metamorphic · igneous · volcanic · zircon · radiometric · petrology · outcrop
Stable ancient continental core
- gneissFoliated metamorphic rock
- lithosphereCrust plus upper mantle
- tectonicsStudy of crustal deformation
- orogenyGeological mountain formation
Layered sedimentary bacterial structures
- cyanobacteriaPhotosynthetic bacteria producing oxygen
- prokaryotesOrganisms without membrane-bound nuclei
- microfossilsMinute preserved organism remains
- anaerobicNot requiring oxygen
chemosynthesis · photosynthesis · unicellular · archaea · bacteria · thermophiles · extremophiles · abiogenesis
Eon before complex life
- PrecambrianEarliest geological eon
- geochronologyStudy of geological ages
- deep timeImmense spans of Earth's history
- geologic timeEarth's age measured epochally
Lacking molecular oxygen
- methaneSimplest alkane fuel
- carbon dioxideRespiration byproduct, photosynthesis fuel
- nitrogenElement seven, colorless gas
- water vaporH₂O in gaseous state
greenstone
Metamorphosed rock, often jade
amphibolite · chert · metamorphic · igneous · volcanic · zircon · radiometric · petrology · outcrop
craton
Stable ancient continental core
- gneissFoliated metamorphic rock
- lithosphereCrust plus upper mantle
- tectonicsStudy of crustal deformation
stromatolites
Layered sedimentary bacterial structures
- cyanobacteriaPhotosynthetic bacteria producing oxygen
- prokaryotesOrganisms without membrane-bound nuclei
- microfossilsMinute preserved organism remains
anaerobic · chemosynthesis · photosynthesis · unicellular · archaea · bacteria · thermophiles · extremophiles · abiogenesis · biogenesis
Proterozoic
Eon before complex life
- PrecambrianEarliest geological eon
- geochronologyStudy of geological ages
- deep timeImmense spans of Earth's history
geologic time · stratigraphy · chronology · timeframe · planetary formation
anoxic
Lacking molecular oxygen
- methaneSimplest alkane fuel
- carbon dioxideRespiration byproduct, photosynthesis fuel
- nitrogenElement seven, colorless gas
ArcheanCenozoic
Present geological era
Quaternary · Holocene · Anthropocene · modern era · Proterozoic
- storytelling archetypeRecurring pattern in tales
- character archetypeStandard fictional personality pattern
- female archetypeUniversal feminine character pattern
- romantic archetypeRecurring beloved character pattern
- heroic archetypeUniversal brave character pattern
- literary archetypeRecurring symbolic pattern in fiction