Using Fossil Leaves to Estimate Climates

April 19 (Tuesday), 6 p.m., Teton Co. Library Auditorium – Open to the Public. Presentation: “Using Fossil Leaves to Estimate Early Eocene Climate of Fossil Basin (Green River Formation), Wyoming.” Presented by Arvid Aase, National Park Service. 

 Spectacular fossil fish are best known from the Eocene Green River Formation of Fossil Basin near Kemmerer Wyoming. Among the fish are found a wide diversity of less common organisms including insects, mollusks, crustaceans, plants, birds, mammals, amphibians and reptiles. This presentation will explain how the fossil leaves are helping us understand the climate of ancient Fossil Lake. Due to the rarity of well-preserved leaves required for study, this project is in its 11th year. Each year we identify more leaf morphotypes which now total 307. Additionally we have identified 109 unique seeds, flowers and other plant parts. This presentation will explain the leaf morphotyping process and the how the leaves are analyzed using Leaf Margin Analysis and Leaf Area Analysis to determine mean annual temperature and mean annual precipitation 52 million years ago.