Stenian

Stenian
Stenian
1200 – 1000 Ma Pha. Proterozoic Archean Had.
	Paleoglobe of Earth during the late Stenian, c. 1040 Ma[citation needed]
Chronology
←	First appearance of Bangiomorpha pubescens
←	Large-scale mountain-building from continent-continent collision of the Grenvillian orogeny
←	Development of the North American Midcontinent Rift
	Events of the Stenian Period. ; Axis scale: millions of years ago.;
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
Upper boundary definition	Defined chronometrically
Upper GSSA ratified	1991

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.

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]

Notes

^ ^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.

"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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