Calymmian

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The Calymmian (from Greek calymma, "cover") is the first geologic period in the Mesoproterozoic Era and lasted from 1600 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 platform covers, or by new platforms on recently cratonized basements.

The supercontinent Columbia broke up during the Calymmian some 1500 Mya.

References[edit]

Preceded by Archean Eon Proterozoic Eon Followed by Phanerozoic Eon
Paleoproterozoic Era Mesoproterozoic Era Neoproterozoic Era
Siderian Rhyacian Orosirian Statherian Calymmian Ectasian Stenian Tonian Cryogenian Ediacaran