The Tidigisian (pron. /ʈiːdɪŋiːsɪn/; from Swedish tidig is, meaning "early ice") is the fourth and final geologic period in the Mesoarchean era. It went from around 2,940 Mya (million years ago) and lasted until 2,900 Mya.
- See Timeline.
- The Pongolan glacation began to occur during this period.
- The supercontinent of Kenorland began to form during this period.
- The Tidigisian-Honolulian extinction happened at the end of this period.