Dating retreat of the NW Laurentide ice sheet: a surface exposure dating transect through NWT
Principal Investigator: Reyes, Alberto (1)
Licence Number: 16828
Organization: University of Alberta
Licensed Year(s): 2021
Issued: May 20, 2021
Project Team: Joseph Young

Objective(s): The objective of this project is to directly date the retreat of the northwest sector of the Laurentide ice sheet at the end of the last ice age, using glacial boulder surface exposure ages at six sites along a ~600-km transect through NWT.

Project Description: This licence has been issued for the scientific research application No.4776.

The objective of this project is to directly date the retreat of the northwest sector of the Laurentide ice sheet at the end of the last ice age, using glacial boulder surface exposure ages at six sites along a ~600-km transect through NWT.

At each of the six sites, the research team will circle the area from the air to locate groups of boulders that were left behind when the ice sheet retreated. The team will then use a cordless saw (or hammer and chisel) to collect a 1 kg sample from the top of five to ten boulders at each site. The team will collect information on boulder elevation, precise location, sediment cover, and any large landforms nearby. In the lab, the team will crush the boulder samples, separate quartz, and extract the element beryllium. The concentration of different beryllium isotopes will allow the team to date when the boulders at each site were deposited by the retreating Laurentide ice sheet. Additional technical details are provided in the uploaded supplemental file.

The principal investigator has been in email contact with the NWT Geological Survey to see if they would like the research team to collect any samples for them in these areas. Wekweètì is the closest community to the study sites (~135 km away). The principal investigator has contacted Tli?cho Government Manager, Lands Protection and Renewable Resources; andWekweètì Chief) to discuss any community concerns with the proposed research and any opportunities for community outreach, including potential school/community visit to Wekweètì to report on the study results. A preliminary progress report will be given at the NWT Geoscience Forum in Fall 2020, with an additional final presentation upon the completion of the project. Copies of all research publications will be forwarded to Aurora Research Institute.

The fieldwork for this study will be conducted from May 21, 2021 to December 31, 2021.