Quaternary Stratigraphy and Glacial Dynamics from a Core Region of the Laurentide Ice Sheet, Aberdeen Lake, Kivalliq, Nunavut

• Main Author: Hodder, Tyler James
• Format: Master Thesis
• Language: English
• Published: University of Waterloo 2014
• Subjects: Laurentide Ice Sheet; Kivalliq; Nunavut; Quaternary Stratigraphy; Glacial Dynamics; Earth Sciences; Aberdeen Lake; Hudson; Hudson Bay; Ice Sheet; Keewatin
• Online Access: http://hdl.handle.net/10012/9086

Central Kivalliq, mainland Nunavut west of Hudson Bay and north of Manitoba, was a long-standing core region of the Laurentide Ice Sheet (LIS). The location of the Keewatin Ice Divide (KID), a major ice spreading region of the LIS, has been shown to have shifted position throughout the Wisconsinan glacial cycle. The surficial record is characterized by near continuous till blanket and cross-cutting streamlined landforms. The occurrence of multi-till stratigraphy across the region raises a number of questions regarding deposition and preservation under a migrating ice divide. This study provides further mapping on the surficial record and investigates the linkages with the subsurface stratigraphy to assess the glacial dynamics evolution throughout the Aberdeen Lake region. This study was motivated by unique access to over 100 drillcores and helicopter based fieldwork, allowing a unique three-dimensional study of the glacial geology record of the Aberdeen Lake region. Field-based mapping of erosional paleo-ice flow indicators, accompanied by remote sensing mapping based on SPOT imagery of subglacial streamlined lineations exhibited a complex surficial history, recording the migration of the KID across the study area. In particular, five paleo-ice flow events are recognized: old WSW (255°) and S (180°) followed by NNW (340°), NW (300°) and finally W (270°) ice flow phases. Landforms corresponding with the NNW, NW and W ice flow phases are recognized. Landforms corresponding to the NNW ice flow phase are part of a larger northward converging landform tract that extends into northern Kivalliq. Southeast of Aberdeen Lake, a paleo-ice stream onset region was interpreted based on the erosional and depositional record observed. Quaternary stratigraphy southeast of Aberdeen Lake can reach up to 71 m in thickness, with till stratigraphy reaching 36 m in thickness. The regional till stratigraphy is grouped into five till lithofacies (Dmm 1-5 – oldest to youngest) based on their texture, geochemistry, lithological signature ...