Glacials/Definition

Term used in glaciology for periods of time in which the northern and southern hemispheres were were extensively covered by ice sheets. Glacial stages are also known as ice ages. They occurred during the Pleistocene Epoch (2.58 Ma to 10 ka), ranging from the Biber/Tegelen and Pre-Illinoian Glacials during the Gelasian Stage to the Würm/Wisconsin Glacial (often called the "Last Ice Age"), the end of which marks the beginning of the Holocene Epoch.