Stenian

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Stenian
1200 – 1000 Ma
Period
Stratigraphic unitSystem
Time span formalityFormal
Lower boundary definitionDefined chronometrically
Lower GSSA ratified1991[4]
Upper boundary definitionDefined chronometrically
Upper GSSA ratified1991[4]

The Stenian Period (

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]

See also

  • Boring Billion – Earth history, 1.8 to 0.8 billion years ago
  • Riphean (stage) – stage in the geological timescale named after the Urals

Notes

References