The Glacial History of Mount Shasta

Geologic Time Scale

Mount Shasta formed during the Pleistocene and was glaciated both during the Pleistocene and the Holocene. The Holocene and Pleistocene are epochs of the Quaternary Period, the most recent period of the Cenozoic era.

Era	Period	Epoch	Event
CENOZOIC (65mya to present)	Quaternary (2 mya-present)	Holocene 10,000 years ago to present	Modern Humans
	Quaternary (2 mya-present)	Pleistocene 2 million years ago to 10,000 years ago	Homo
	Tertiary		Age of Mammals
MESOZOIC 220mya to 65mya			Age of Dinosaurs
PALEOZOIC 625mya to 220mya			Age of Ancient Life