CAREER: Quantifying climate induced landscape evolution during early Eocene hyperthermals

University Of Minnesota-Twin Cities, Minneapolis MN

Investigators

Abstract

The US has incurred billions of dollars in damage from extreme precipitation events linked to anthropogenic climate change since the 1980s. Increased erosion and sediment yield from these events is likely to damage soils, clog rivers, and cripple hydraulic infrastructure. However, we have little information on the magnitude of the response of our rivers and landscapes to global climate change because these changes occur on timescales difficult to measure in our lifetimes. Therefore, we must look to times in Earth’s past when temperatures and atmospheric CO¬2 concentrations rose rapidly to study landscape response. During the early Eocene, approximately 56 to 52 million years ago, there were repeated intervals known as hyperthermal events where global temperatures rapidly increased due to releases of CO2 over a period of ~20,000 years. These hyperthermals provide one of the best analogs to modern anthropogenic climate change, albeit at a slower rate than today. This project will focus on improving scientific and public understanding of how future climate change will affect our river systems by using analogs from the early Eocene in New Mexico, Wyoming, and North Dakota. The education plan will target a diverse population of students from the University of Houston that will strengthen undergraduate exposure to field geology using virtual field trips. Because climate change can be an abstract and intimidating concept for some groups, collaborations with a world-renowned climate-artist will be used to break down mental barriers and communicate science to the public and low-income and minority students from the Houston area. This project will generate new terrestrial paleoclimate records from three fluvially dominated basins in the western US: 1) San Juan Basin of New Mexico, 2) Wind River Basin of Wyoming, and 3) Williston Basin of North Dakota. It will use a novel method that integrates datasets from both sandstone channel facies and floodplain paleosols to test the hypothesized connection between hyperthermal-driven hydrologic cycle intensification and increased weathering that formed large sand bodies and thick packages of kaolinite. This project will use a multi-proxy approach that includes geochemistry, mineralogy, stable isotopes (δ13C, δ18O, and Δ47), sedimentology, stratigraphy, radiogenic isotope geochronology (40Ar/39Ar, U-Th-Pb), and magnetostratigraphy to reconstruct the paleoclimate and constrain landscape response to the hyperthermal events both spatially and temporally. The resulting dataset will be integrated into quantitative models to test how rapid atmospheric CO2 increases, global warming, and the resulting hydrologic cycle intensification will increase the magnitude of weathering and sediment yield, which has the potential to cause billions of dollars in damage to infrastructure and ecosystems from soil loss, erosion, and increased flooding. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.