Paleoarchean Era
E226440
The Paleoarchean Era is an early division of Earth's geologic history marked by the stabilization of the first continental crust and the emergence of some of the oldest known life forms.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Paleoarchean Era canonical | 4 |
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
Archean era
ⓘ
geologic era ⓘ |
| associatedWith |
early plate tectonic activity or proto-plate tectonics
ⓘ
formation of early oceanic crust ⓘ growth of early continental crust ⓘ |
| characterizedBy |
anoxic atmosphere
ⓘ
development of early continental nuclei ⓘ emergence of some of the oldest known life forms ⓘ formation of some of the first stable cratons ⓘ greenhouse atmosphere dominated by CO2 and other gases ⓘ high heat flow from Earth’s interior ⓘ intense volcanic activity ⓘ lack of free molecular oxygen in the atmosphere ⓘ presence of early microbial life ⓘ rapid tectonic processes compared with later eons ⓘ stabilization of early continental crust ⓘ warm surface temperatures ⓘ |
| chronostratigraphicRank | era ⓘ |
| contains |
some of the oldest known microfossils
ⓘ
some of the oldest known sedimentary rocks ⓘ some of the oldest known stromatolites ⓘ |
| definedBy | absolute age boundaries rather than global stratotype section ⓘ |
| endTime |
3.2 Ga
ⓘ
about 3.2 billion years ago ⓘ |
| environmentalCondition |
largely ice-free oceans despite lower solar output
ⓘ
reduced solar luminosity compared with present ⓘ strong greenhouse effect compensating for faint young Sun ⓘ |
| follows | Eoarchean Era ⓘ |
| geologicTimeScaleUsedBy | International Commission on Stratigraphy ⓘ |
| hasGlobalContext |
Earth’s surface dominated by oceans with small protocontinents
ⓘ
high meteorite impact rate relative to later eons ⓘ |
| importance |
records early evolution of Earth’s biosphere
ⓘ
records early evolution of Earth’s crust ⓘ |
| lifeEvidenceType |
carbon isotopic signatures consistent with biological activity
ⓘ
microbial mat structures ⓘ stromatolitic structures ⓘ |
| lifeForms |
archaea-like organisms
ⓘ
bacteria-like organisms ⓘ prokaryotic microorganisms ⓘ |
| partOf | Archean Eon ⓘ |
| positionInArchean | earliest formally recognized era after the Eoarchean ⓘ |
| precededBy | Hadean Eon in broader Earth history ⓘ |
| precedes | Mesoarchean Era ⓘ |
| startTime |
3.6 Ga
ⓘ
about 3.6 billion years ago ⓘ |
| tectonicStyle |
frequent crustal recycling
ⓘ
possibly dominated by smaller, more mobile plates ⓘ |
Referenced by (4)
Full triples — surface form annotated when it differs from this entity's canonical label.