Boulder, Colo., The Marcellus Shale is famous as a formation being explored for natural gas resources. That exploration has also offered some insight into an age-old problem: where was the continent of North America 400 million years ago?
In a research partnership between Lehigh University and The Pennsylvania State University, subterranean rock samples have been used to help fill a gap in the history of Earth's magnetic field, and, as a corollary, places some constraints on the position of North America when the Marcellus Formation was deposited.