Geoscience students uncover Between 335 and 256 million years ago, the landmasses of the southern hemisphere were squished together in a super continent called Gondwana. Gripped in the cold throes of an Ice Age, glaciers moved slowly across the landscape, churning up ground and leaving a trail of sediment in their wake. They retreated as the Earth warmed, transitioning from an icehouse to a greenhouse climate at the end of the Paleozoic Era. Today, UWM geosciences students are studying those glacier trails, hoping to discover information about the past that might help us understand our warming climate in the present. Nailing down the geologic record Since about the 1960s, said distinguished professor of geosciences John Isbell, scientists have worked under the idea that Gondwana was covered by one giant glacier, buried under ice for over 100 million years. But, he said, when studied in detail, the geology tells a different story. Drawing on research about ancient sea levels, Isbell determined that the late Paleozoic oceans were not
Geosciences graduate student Libby Ives perches on an outcrop in Antarctica where she researches glacial movement during the late Paleozoic Ice Age. Photo by John Isbell.
6 • IN FOCUS • February, 2019
