Pleistocene « Back to Glossary IndexThe epoch of the ice ages roughly 2 mya to 12 kya. Alternative Meanings: Pleistocenetime period from 2 mya to abut 10 kya marked by ice ages (cold trends) and warming period (interglacials); climate during the Pleistocene was highly variablePleistoceneA geological epoch from 2.5 million to 11,700 years ago that's characterized by increased glacial activity and megafauna.