Tonian
Sign in to saveAlso known as Tonian Period, Tonian System
The Tonian (from , meaning "stretch") is the first geologic period of the Neoproterozoic Era. It lasted from to Mya (million years ago). Instead of being based on stratigraphy, these dates are defined by the ICS based on radiometric chronometry. The Tonian is preceded by the Stenian Period of the Mesoproterozoic Era and followed by the Cryogenian.
Key facts
- Geologic timespan.name
- Tonian
- Geologic timespan.color
- Tonian
- Geologic timespan.top_bar
- all time
- Geologic timespan.time_end_prefix
- ~
- Geologic timespan.image_map
- Mollweide Paleographic Map of Earth, 750 Ma (Tonian Period).png
- Geologic timespan.caption_map
- A map of Earth as it appeared during the late Tonian, 750 Ma
- Geologic timespan.timeline
- Tonian
- Geologic timespan.name_formality
- Formal
- 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
- Geologic timespan.upper_boundary_def
- Redefined chronometrically with an interim calibrated age of c. 720 Ma. GSSP is in progress. (Previously defined chronometrically as 850 Ma)
- Geologic timespan.upper_def_candidates
- The first appearance of widespread glaciation.
- Geologic timespan.upper_gssp_candidates
- To be determined
via Wikipedia infobox
Wikidata facts
- Image
- Rodinia 900Ma.jpg
Show 4 more facts
- sRGB color hex triplet
- FEBF4E
- start time
- 1000000000
- end time
- 720000000-
- Commons category
- Tonian
Sources (3)
via Wikidata · CC0
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Article
6 sectionsContents
- History
- Geology
- Biology
- See also
- References
- Further reading
The Tonian (from , meaning "stretch") is the first geologic period of the Neoproterozoic Era. It lasted from to Mya (million years ago). Instead of being based on stratigraphy, these dates are defined by the ICS based on radiometric chronometry. The Tonian is preceded by the Stenian Period of the Mesoproterozoic Era and followed by the Cryogenian.
== History == The Tonian was defined in 1990 by the New Precambrian time scale as being from 1000 to 850 Mya. The name Tonian comes from , which means the word "stretch", referring to the rifting that broke up Rodinia during this period. The upper definition was then redefined to 720 Mya in 2014 after discoveries that the original 850 Mya for the lower Cryogenian and the first glaciations at 717 Mya did not match. This is temporary until the basal Cryogenian GSSP is chosen.