The Bighorn Basin in Wyoming has been an important area for research into terrestrial ecosystems for decades. The basin formed as part of the uprising of the Rocky Mountains in the west of North America, and sediment from the surrounding mountain ranges was transported into it for millions of years, building up a huge thickness that has fossils from all kinds of life on land preserved within it. Rocks from many different time periods are now exposed in the basin, but a particularly important one is the Paleocene Eocene thermal maximum (PETM) which occurred around 56 million years ago. At this time a huge amount of carbon was released into the atmosphere very quickly, causing a sharp (by geological standards) increase in temperature and dramatic effects on life. Palaeontologists and geologists are particularly interested in studying the PETM as it can potentially give us lots of information about how life and earth systems might respond in the near future to the large quantities of carbon being released into our atmosphere now by humans.

In this episode recorded in the field we talk to Dr Scott Wing, who is curator of fossil plants at the Smithsonian in Washington DC but has been coming to the basin every summer for decades. We chat about the geology and history of the area, what it's like to work in the Wyoming desert every summer, how to find and collect fossil plants, and what years of research by many people in the basin has told us about the PETM.