Calymmian (Geological periods 🌍)

The Calymmian Period is the first geologic period in the Mesoproterozoic Era and lasted from 1600 Mya to 1400 Mya. 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...

https://en.wikipedia.org/wiki/Calymmian

#Calymmian #Mesoproterozoic #GeologicalPeriods #ProterozoicGeochronology