| Neoarchean | |
|---|---|
| 2800 – 2500 Ma | |
| Chronology | |
-4500 — – -4000 — – -3500 — – -3000 — – -2500 — – -2000 — – -1500 — – -1000 — – -500 — – 0 — Scale: millions of years | |
| Proposed redefinition(s) | 2780–2420 Ma Gradstein et al., 2012 |
| Proposed subdivisions | Methanian Period, 2780–2630 Ma Gradstein et al., 2012 |
| Etymology | |
| Name formality | Formal |
| Alternate spelling(s) | Neoarchaean |
| Usage information | |
| Celestial body | Earth |
| Regional usage | Global (ICS) |
| Time scale(s) used | ICS Time Scale |
| Definition | |
| Chronological unit | Era |
| Stratigraphic unit | Erathem |
| Time span formality | Formal |
| Lower boundary definition | Defined Chronometrically |
| Lower boundary GSSP | N/A |
| GSSP ratified | N/A |
| Upper boundary definition | Defined Chronometrically |
| Upper boundary GSSP | N/A |
| GSSP ratified | N/A |
The Neoarchean (/ˌniːoʊɑːrˈkiːən/; also spelled Neoarchaean) is a geologic era within the Archaean Eon.
The Neoarchean spans the period from 2,800 to 2,500 million years ago— the period being defined chronometrically and not referenced to a specific level in a rock section on Earth.
Complex life
During this era, oxygenic photosynthesis first evolved, releasing an abundance of oxygen, that first reacted with minerals and afterward was free to react with greenhouse gases of the atmosphere, leaving the Earth's surface free to radiate its energy to space. This is known as the oxygen catastrophe which was to happen later in the Paleoproterozoic from a poisonous buildup of oxygen in the atmosphere, released by these oxygen-producing photoautotrophs, which evolved earlier in the Neoarchean.
Continental formation
During this era, the supercontinent Kenorland formed at about 2,720 million years ago.[1]:316
References
- ^ Bozhko, N. A. (2011). "On Two Types of Supercontinental Cyclicity". Moscow University Geology Bulletin. 66: 313–322.
External links