Stenian

The Stenian Period (from Greek στενός (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.

Stenian Period 1200–1000 million years ago PreꞒ Ꞓ O S D C P T J K Pg N

Paleoglobe of Earth during the Stenian period

Events of the Stenian -1200 — – -1180 — – -1160 — – -1140 — – -1120 — – -1100 — – -1080 — – -1060 — – -1040 — – -1020 — – -1000 — – M e s o p r o t e r o z o i c N P Z Ectasian Stenian Tonian     ← Precipitous drop in Stromatolite Population (Forams to blame?)[1] Events of the Stenian Period. Axis scale: millions of years ago.

Preceded by the Ectasian period and followed by the Neoproterozoic Era.

The supercontinent Rodinia assembled during the Stenian. It would last into the Tonian period.

This period includes the formation of the Keweenawan Rift at about 1100 Mya.[2]

Fossils of the oldest known sexually reproducing organism, Bangiomorpha pubescens, first appeared in the Stenian.[3]

See also

• Boring Billion – Between 1.8 and 0.8 billion years ago
• Riphean (stage)

Notes

1. Bernhard, Joan (11 June 2013). "Insights into foraminiferal influences on microfabrics of microbialites at Highborne Cay, Bahamas". Proceedings of the National Academy of Sciences of the United States of America. 110 (24): 5. doi:10.1073/pnas.1221721110. Retrieved 28 February 2020.
2. "Organic geochemical study of mineralization in the Keweenawan Nonesuch Formation at White Pine, Michigan" (PDF). University of Michigan. Retrieved 28 September 2011.
3. 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.

References

• "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.