Calymmian

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Calymmian
1600 – 1400 Ma
Period
Stratigraphic unitSystem
Time span formalityFormal
Lower boundary definitionDefined chronometrically
Lower GSSA ratified1991[1]
Upper boundary definitionDefined chronometrically
Upper GSSA ratified1991[1]

The Calymmian Period (from

Mya to 1400 Mya (million years ago). Instead of being based on stratigraphy, these dates are defined chronometrically
.

The period is characterised by expansion of existing

.

The supercontinent Columbia started to break up during the Calymmian some 1500 Mya.

The Volyn biota have been dated to 1500 Mya.

See also

  • Boring Billion – Earth history, 1.8 to 0.8 billion years ago
  • Jotnian – Oldest known sediments in the Baltic area that have not been subject to metamorphism

References

  • "Calymmian 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. .