Meltwater drainage through the Mackenzie Mountains, Northwest Territories, during the last deglaciation
Principal Investigator: Stoker, Benjamin James (1)
Licence Number: 16989
Organization: Charles University
Licensed Year(s): 2022
Issued: Mar 14, 2022
Project Team: Helen Dulfer, Sophie Norris, Joseph Young

Objective(s): To investigate the meltwater drainage and deglacial history of the Laurentide Ice Sheet from the eastern slopes of the Mackenzie Mountains since the last ice age.

Project Description: This licence has been issued for the scientific research application No.5163. In this project the research team aim to investigate the meltwater drainage and deglacial history of the Laurentide Ice Sheet from the eastern slopes of the Mackenzie Mountains since the last ice age. The research team will reconstruct the past meltwater flow characteristics (discharge and velocity) through a series of large channels in the Mackenzie Mountains conduct detailed stratigraphic studies of fluvial landforms to understand the processes responsible for landscape formation. The research team also aim to establish a chronology for meltwater drainage through the Mackenzie Mountains using numerical dating methods. This will provide a greater understanding of the timing and magnitude of freshwater fluxes to the Arctic Ocean and the implications for past changes in ocean circulation and climate changes. Geomorphological mapping from remote sensing data has identified a series of large meltwater channels in the eastern Mackenzie Mountains. The proposed fieldwork will target sites in Grotto Creek (64 32' 37'' N / 126 41' 43'' W) with two main work phases. The first phase aims to reconstruct past flow characteristics (flow discharge and velocity) and understand the processes responsible for meltwater channel formation. In the field, this will involve collecting information on past flow level indicators (e.g. fluvial landforms and wash limits), this information is essential to model the past water discharge. Maximum boulder sizes will also be recorded to provide an estimate of the shear stress and further constrain flow discharge. Secondly, detailed stratigraphic studies of fluvial landforms will be undertaken. These investigations will target a series of streamlined ridges near the field camp location and other fluvial landforms. This will allow us to investigate the erosional and depositional processes operating during channel formation. This phase of research is nondestructive and will simply record geological observations without removing any material from the environment. The second phase of work aims to date the drainage of meltwater through the Mackenzie Mountains. This would include collecting sediment samples for Optically Stimulated Luminescence (OSL) dating, or rock samples for cosmogenic nuclide dating. For OSL dating, samples of river sand will be collected from stratigraphic sections. No more than 5 OSL samples will be taken, and each sample will consist of less than 1kg of material. For cosmogenic nuclide dating, rock samples will be removed from boulders or bedrock exposures. An area of up to 15 x 15 cm will be sampled, removing the upper 2-3 cm of rock. Up to 15 different exposures may be sampled by this technique. The sampling strategy for these techniques is designed to minimise the material removed and result in a negligible impact on the landscape. The scientific outputs and any project reports related to this project will be sent to the Aurora Research Institute and any appropriate local communities. If the research team are invited, the team would happily present the project to the Ne? K’? Dene Ts’i?li? Forum. If there is any interest from local communities, further discussion events could be organized. This can include online presentations which are freely open to the public. The research will lead to improved knowledge of the natural history and the processes that shaped the landscape of the Northwest Territories. This knowledge is of great interest to the communities of the Northwest Territories and to potential visitors to the region. The fieldwork for this study will be conducted from May 22, 2022 - July 03, 2022