Authors: Cate Bateman, Jose Aurelio De La Rocha Tapia, Ethan Fulwood, Arianna Harrington
Mentors: Arianna Harrington
Insitution: Southern Utah University
The Eocene-Oligocene boundary in North America was marked by climatic cooling and drying. This transition is a key time in mammalian evolution, and studying fossils spanning this boundary could yield important information about how fauna responded to the climatic change. McCarty’s Mountain, a fossil rich geological feature located in Madison County, Montana, has long intrigued scientists due to the many insights it holds into the terrestrial fauna of the region. The sites from McCarty’s Mountain date from the Chadronian North American Land Mammal Age, which corresponds to the late Eocene epoch. The geological strata to produce these fossils were thought to have been deposited in a floodplain, yielding remarkably preserved fossils which have been collected and studied since the early 1900’s. However, the microfossils from this locality have been understudied despite the insights it could provide to the terrestrial Eocene-Oligocene transition in North America. In this study, we aim to close this gap by analyzing microfossils picked from matrix collected from McCarty’s Mountain localities in summer 2023. Preliminarily, we have processed about ⅛ of the collected sediments, and have found several identifiable elements including mammalian teeth, vertebrae, and long bones. We will continue this work by washing and soaking the remaining matrix and quantifying the microfossils retrieved. The fossils recovered may provide future insight to changes in microfauna across the Eocene-Oligocene boundary.