Cryogenian
Sign in to saveThe Cryogenian (from , meaning "cold" and , romanized: , meaning "birth") is a geologic period that lasted from . It is the second of the three periods of the Neoproterozoic era, preceded by the Tonian and followed by the Ediacaran.
Key facts
- Geologic timespan.name
- Cryogenian
- Geologic timespan.color
- Cryogenian
- Geologic timespan.top_bar
- all time
- Geologic timespan.time_start_prefix
- ~
- Geologic timespan.time_end_prefix
- ~
- Geologic timespan.image_map
- Mollweide Paleographic Map of Earth, 690 Ma (Cryogenian Period).png
- Geologic timespan.caption_map
- A map of Earth as it may have appeared during the early Cryogenian, 690 Ma
- Geologic timespan.timeline
- Cryogenian
- Geologic timespan.name_formality
- Formal
- Geologic timespan.name_accept_date
- 1990
- Geologic timespan.celestial_body
- earth
- Geologic timespan.usage
- Global (ICS)
- Geologic timespan.timescales_used
- ICS Time Scale
- Geologic timespan.chrono_unit
- Period
- Geologic timespan.strat_unit
- System
- Geologic timespan.timespan_formality
- Formal
- Geologic timespan.lower_boundary_def
- Defined chronometrically with an interim calibrated age of c. 720 Ma. GSSP is in progress.
- Geologic timespan.lower_def_candidates
- The first appearance of widespread glaciation.
via Wikipedia infobox
Article
8 sectionsContents
- Ratification
- Climate
- Paleogeography
- Cryogenian biota and fossils
- See also
- References
- Further reading
- External links
The Cryogenian (from , meaning "cold" and , romanized: , meaning "birth") is a geologic period that lasted from . It is the second of the three periods of the Neoproterozoic era, preceded by the Tonian and followed by the Ediacaran.
The Cryogenian was a time of drastic climate changes. After the long environmental stability/stagnation during the Boring Billion, the Sturtian glaciation began at the beginning of Cryogenian, freezing the entire planet in a state of severe icehouse climate known as a snowball Earth. After 70 million years it ended, but was quickly followed by another global ice age, the Marinoan glaciation. There is controversy over whether these glaciations indeed covered the entire planet, or whether a band of open sea survived near the equator (i.e. "slushball Earth"), but the extreme climates with massive expanse of ice sheets blocking off sunlight would nevertheless have significantly hindered primary production in the shallow seas and caused major mass extinctions and biosphere turnovers.