ScienceDaily: Fossils & Ruins News

New research definitively resolves a long-standing discrepancy in the geologic record that pitted studies of marine ice-sheet behavior against those that reconstructed past conditions on land. The research lends additional weight to evidence that the Antarctic Ice Sheet is sensitive to small changes in carbon dioxide levels and that, in the past, large portions of the ice sheet could have disappeared under carbon dioxide levels similar to today.

As ice sheets began melting at the end of the last ice age, a series of cataclysmic floods called the Missoula megafloods scoured the landscape of eastern Washington, carving long, deep channels and towering cliffs through an area now known as the Channeled Scablands. They were among the largest known floods in Earth's history, and geologists struggling to reconstruct them have now identified a crucial factor governing their flows. A new study shows how the changing weight of the ice sheets would have caused the entire landscape to tilt, changing the course of the megafloods.

Several dozen small impact craters, 10--70-m in size, have been discovered in southeastern Wyoming. A team of U.S. and German geoscientists found these ancient craters in exposed sedimentary layers from the Permian period (280 million years ago). After discovering the first craters, the team initially suspected that they are a crater-strewn field, formed by the breakup of an asteroid that entered the atmosphere. However, with the discovery of more and more craters over a wide area, this interpretation was ruled out.