Karoo Ice Age

The Karoo Ice Age from 360–260 Ma (million years ago) was the second major ice age of the Phanerozoic Eon. It is named after the glacial tills found in the Karoo region of South Africa where evidence for this ice age was first clearly identified.

The tectonic assembly of the continents of Euramerica (later with the Uralian orogeny, into Laurasia) and Gondwana into Pangaea, in the Hercynian-Alleghany Orogeny, made a major continental landmass within the Antarctic region, and the closure of the Rheic Ocean and Iapetus Ocean saw disruption of warm water currents in the Panthalassa Ocean and Paleotethys Sea, which led to progressive cooling of summers, and the snowfields accumulating in winters, causing mountainous alpine glaciers to grow, and then spread out of highland areas, making continental glaciers which spread to cover much of Gondwana.

At least two major periods of glaciation have been discovered:-

• The first glacial period was associated with the Mississippian Period (359.2–318.1 Ma): ice sheets expanded from a core in southern Africa and South America.
• The second glacial period was associated with the Pennsylvanian Period (318.1–299 Ma); ice sheets expanded from a core in Australia and India.

The extent of glaciation in Antarctica is not exactly known, due to its present ice sheet.