Archean Eon
E43458
The Archean Eon is an ancient geological eon of Earth's history, spanning from about 4.0 to 2.5 billion years ago, characterized by the formation of the first stable continental crust and the earliest known life.
All labels observed (7)
| Label | Occurrences |
|---|---|
| Archean Eon canonical | 25 |
| Archean | 4 |
| Archaean Eon | 2 |
| Archean eon | 2 |
| Archaean | 1 |
| Archeozoic Eon | 1 |
| Neoarchean Era | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T335896 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Archean Eon Context triple: [Proterozoic Eon, follows, Archean Eon]
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A.
Precambrian Supereon
The Precambrian Supereon is the vast span of Earth's early history before the Phanerozoic, encompassing the Hadean, Archean, and Proterozoic eons during which the planet formed, life first appeared, and early continents and atmospheres developed.
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B.
Proterozoic Eon
The Proterozoic Eon is a major division of Precambrian time, spanning from about 2.5 billion to 541 million years ago, marked by the buildup of atmospheric oxygen, the emergence of complex single-celled and early multicellular life, and the assembly of large continental landmasses.
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C.
Paleozoic Era
The Paleozoic Era was an ancient geologic time interval, spanning roughly 541 to 252 million years ago, marked by the emergence and diversification of complex life in the seas and on land and the assembly of major continental landmasses.
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D.
Phanerozoic Eon
The Phanerozoic Eon is the current and most recent major division of Earth's history, marked by abundant fossil evidence and the evolution and diversification of complex life forms, including plants, animals, and eventually humans.
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E.
Early Devonian
The Early Devonian was the initial subdivision of the Devonian Period, marked by the diversification of early fishes and the spread of primitive vascular land plants across emerging terrestrial ecosystems.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Archean Eon Target entity description: The Archean Eon is an ancient geological eon of Earth's history, spanning from about 4.0 to 2.5 billion years ago, characterized by the formation of the first stable continental crust and the earliest known life.
-
A.
Precambrian Supereon
The Precambrian Supereon is the vast span of Earth's early history before the Phanerozoic, encompassing the Hadean, Archean, and Proterozoic eons during which the planet formed, life first appeared, and early continents and atmospheres developed.
-
B.
Proterozoic Eon
The Proterozoic Eon is a major division of Precambrian time, spanning from about 2.5 billion to 541 million years ago, marked by the buildup of atmospheric oxygen, the emergence of complex single-celled and early multicellular life, and the assembly of large continental landmasses.
-
C.
Paleozoic Era
The Paleozoic Era was an ancient geologic time interval, spanning roughly 541 to 252 million years ago, marked by the emergence and diversification of complex life in the seas and on land and the assembly of major continental landmasses.
-
D.
Phanerozoic Eon
The Phanerozoic Eon is the current and most recent major division of Earth's history, marked by abundant fossil evidence and the evolution and diversification of complex life forms, including plants, animals, and eventually humans.
-
E.
Early Devonian
The Early Devonian was the initial subdivision of the Devonian Period, marked by the diversification of early fishes and the spread of primitive vascular land plants across emerging terrestrial ecosystems.
- F. None of above. chosen
Statements (50)
| Predicate | Object |
|---|---|
| instanceOf | geological eon ⓘ |
| alsoKnownAs |
Archaean Eon
ⓘ
linked to:
Archean Eon
Archeozoic Eon ⓘ
linked to:
Archean Eon
|
| associatedWith |
formation of Pilbara Craton
ⓘ
formation of Superior Craton ⓘ formation of major cratons such as Kaapvaal Craton ⓘ |
| atmosphereComposition |
dominated by nitrogen and carbon dioxide
ⓘ
very low molecular oxygen ⓘ |
| biosphere |
dominated by prokaryotes
ⓘ
presence of cyanobacteria by late Archean ⓘ |
| characterizedBy |
abundant komatiites
ⓘ
anoxic atmosphere ⓘ development of proto-continents ⓘ dominance of mafic and ultramafic rocks ⓘ earliest known life on Earth ⓘ early oceans ⓘ emergence of stable cratons ⓘ formation of first stable continental crust ⓘ high geothermal heat flow ⓘ limited free oxygen in atmosphere ⓘ microbial life ⓘ more intense volcanism than today ⓘ presence of greenstone belts ⓘ stromatolite formation ⓘ |
| climate |
Sun fainter than today
ⓘ
possible greenhouse warming to keep oceans liquid ⓘ |
| contains |
oldest known continental crust fragments
ⓘ
oldest known sedimentary rocks ⓘ oldest known stromatolites ⓘ oldest widely accepted microfossils ⓘ |
| duration | about 1.5 billion years ⓘ |
| endTime | 2.5 billion years ago ⓘ |
| endTimeUpperBound | about 2,500 million years ago ⓘ |
| follows | Hadean Eon ⓘ |
| importance |
records earliest preserved history of Earth’s crust
ⓘ
records origin and early evolution of life ⓘ |
| meaningOfName | ancient ⓘ |
| namedAfter | Greek word "archaios" ⓘ |
| oceanChemistry | likely rich in dissolved iron ⓘ |
| partOf |
Precambrian Supereon
ⓘ
geologic time scale ⓘ |
| precedes | Proterozoic Eon ⓘ |
| startTime | 4.0 billion years ago ⓘ |
| startTimeLowerBound | about 4,000 million years ago ⓘ |
| subdividedInto |
Eoarchean Era
ⓘ
Mesoarchean Era ⓘ Neoarchean Era ⓘ Paleoarchean Era ⓘ |
| tectonics |
early forms of plate tectonics debated
ⓘ
possible stagnant-lid or proto-plate tectonic regime ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Archean Eon Description of subject: The Archean Eon is an ancient geological eon of Earth's history, spanning from about 4.0 to 2.5 billion years ago, characterized by the formation of the first stable continental crust and the earliest known life.
Referenced by (36)
Full triples — surface form annotated when it differs from this entity's canonical label.
linked to: Archean Eon
linked to: Archean Eon
linked to: Archean Eon
linked to: Archean Eon
linked to: Archean Eon
linked to: Archean Eon
linked to: Archean Eon
linked to: Archean Eon
linked to: Archean Eon
linked to: Archean Eon
linked to: Archean Eon