Coring project in Bighorn Basin: Drilling phase complete

Abstract

Scientists have begun a new project to recover and study sediment cores in the Bighorn Basin of Wyoming to investigate the high-frequency climatic and biotic variability of a continental depositional system during past episodes of greenhouse conditions. The project, called the Bighorn Basin Coring Project (BBCP), focuses on the early Paleogene (∼50-65 million years ago), the most recent interval of Earth history characterized by greenhouse climate conditions. During the early Paleogene, global mean annual temperatures were up to 10C higher than today, and carbon dioxide (CO 2) concentrations may have been more than 1000 parts per million [Zachos et al., 2008] compared with the roughly 390 parts per million today. Superimposed on this background greenhouse climate state were a series of short-term extreme warming events called hyperthermals. The best known early Paleogene hyperthermal event is the Paleocene-Eocene Thermal Maximum (PETM; ∼56 million years ago), which is characterized by a large global carbon isotope excursion and coincides with major changes to marine and continental ecosystems [McInerney and Wing, 2011]. At present, the causes of these hyperthermal events remain unknown, although several hypotheses exist.