Postdoctoral Fellowship: EAR-PF: Pairing on-and-offshore observations of paleo-ice streams to constrain and elucidate dynamics of the Cordilleran Ice Sheet (PISCES)

Mckenzie, Marion, Charlottesville VA

Investigators

Abstract

Dr. Marion McKenzie has been awarded an NSF Earth Sciences Postdoctoral fellowship to carry out research and professional development activities at Colorado School of Mines under the mentorship of Dr. Ryan Venturelli. Dr. McKenzie seeks to resolve relationships between terrestrial (onshore) and marine (offshore) records of glaciation. The factors that controlled the Cordilleran Ice Sheet (CIS) when it covered western North America about 20,000 years ago are not well understood. Using onshore and offshore records of glaciation, this project will improve understanding of Pacific Ocean and CIS dynamics through time. This work also seeks to provide insight into the factors that influence ice sheet contributions to sea level rise, which will ultimately help in constraining how ice in modern systems may contribute to sea level rise in the future. The fellowship funding creates opportunities for undergraduate students to conduct research. In addition, this project will support development of educational materials for college-level and Alaska Native Science & Engineering Program students. The deglacial history of Cordilleran Ice Sheet (CIS) marine margins over the last 50,000 years is poorly constrained despite the potential insights this record may contribute to identifying controls on ice stream stability, elucidating millennial and global-scale climate oscillations, and characterizing paleo-current dynamics across the Pacific Ocean. The proposed project will leverage techniques from the fields of sedimentology, geochronology, geophysics, and glaciology to constrain the spatiotemporal retreat dynamics of relict ice streams near the Queen Charlotte Sound. Principally, the researchers will supplement mapping of glacial geomorphic landforms from LiDAR and bathymetric elevation data with iceberg-rafted debris (IRD) and offshore marine sediment geochronology from Deep Sea Drilling Project (DSDP) cruise 18, site 177 to constrain the location, behavior, timing, and rate of southwestern CIS ice stream activity over the last 50,000 years. Pairing on-and-offshore data will lead to strong temporal and spatial records of paleo-glaciation with implications for overall CIS modelling, ocean dynamics in the Pacific Ocean, and millennial-scale climate oscillations to bolster understanding of dynamics, rates, and magnitude of change in the Earth climate system. Multidisciplinary techniques used throughout this work will improve understanding of controls on ice streams suitable for predicting dynamics of future ice loss to ultimately elucidate the relationship between onshore and offshore records. 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.