The Stenian Period (/ˈstiːni.ən/ STEE-nee-ən, from Ancient Greek: στενός, romanized: stenós, meaning "narrow") is the final geologic period in the Mesoproterozoic Era and lasted from 1200 Mya to 1000 Mya (million years ago). Instead of being based on stratigraphy, these dates are defined chronometrically. The name derives from narrow polymetamorphic belts formed over this period. It is preceded by the Ectasian Period and followed by the Neoproterozoic era and the Tonian period.
| Stenian | |||||||||||||
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 Paleoglobe of Earth during the late Stenian, c. 1040 Ma[citation needed] | |||||||||||||
| Chronology | |||||||||||||
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| Etymology | |||||||||||||
| Name formality | Formal | ||||||||||||
| Usage information | |||||||||||||
| Celestial body | Earth | ||||||||||||
| Regional usage | Global (ICS) | ||||||||||||
| Time scale(s) used | ICS Time Scale | ||||||||||||
| Definition | |||||||||||||
| Chronological unit | Period | ||||||||||||
| Stratigraphic unit | System | ||||||||||||
| Time span formality | Formal | ||||||||||||
| Lower boundary definition | Defined chronometrically | ||||||||||||
| Lower GSSA ratified | 1991[4] | ||||||||||||
| Upper boundary definition | Defined chronometrically | ||||||||||||
| Upper GSSA ratified | 1991[4] | ||||||||||||
The supercontinent Rodinia assembled during the Stenian. It would last into the Tonian period before breaking up in the Cryogenian.
This period includes the formation of the Keweenawan Rift at about 1100 Mya.[5]
Fossils of the oldest known sexually reproducing organism, Bangiomorpha pubescens, first appeared in the Stenian.[1]
See also
edit- Boring Billion – Earth history, 1.8 to 0.8 billion years ago
- Riphean (stage) – stage in the geological timescale named after the Urals
Notes
edit- ^ a b Gibson, Timothy M; Shih, Patrick M; Cumming, Vivien M; Fischer, Woodward W; Crockford, Peter W; Hodgskiss, Malcolm S.W; Wörndle, Sarah; Creaser, Robert A; Rainbird, Robert H; Skulski, Thomas M; Halverson, Galen P (2017). "Precise age of Bangiomorpha pubescens dates the origin of eukaryotic photosynthesis" (PDF). Geology. 46 (2): 135–138. doi:10.1130/G39829.1.
- ^ McLelland, James M.; Selleck, Bruce W.; Bickford, M. E. (2010). "Review of the Proterozoic evolution of the Grenville Province, its Adirondack outlier, and the Mesoproterozoic inliers of the Appalachians". From Rodinia to Pangea: The Lithotectonic Record of the Appalachian Region. doi:10.1130/2010.1206(02). ISBN 9780813712062.
- ^ Swanson-Hysell, Nicholas L.; Ramezani, Jahandar; Fairchild, Luke M.; Rose, Ian R. (2019). "Failed rifting and fast drifting: Midcontinent Rift development, Laurentia's rapid motion and the driver of Grenvillian orogenesis". GSA Bulletin. 131 (5–6): 913–940. doi:10.1130/B31944.1. ISSN 0016-7606.
- ^ a b Plumb, K. A. (June 1, 1991). "New Precambrian time scale". Episodes. 14 (2): 139–140. doi:10.18814/epiiugs/1991/v14i2/005.
- ^ "Organic geochemical study of mineralization in the Keweenawan Nonesuch Formation at White Pine, Michigan" (PDF). University of Michigan. Retrieved 28 September 2011.
References
edit- "Stenian Period". GeoWhen Database. Archived from the original on May 12, 2006. Retrieved January 5, 2006.
- James G. Ogg (2004). "Status on Divisions of the International Geologic Time Scale". Lethaia. 37 (2): 183–199. doi:10.1080/00241160410006492.
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