Geoscience and Exploration

A New Glacial Landscape Map of the Laurentide Ice Sheet in Central Nunavut and Eastern Northwest Territories

Wednesday, November 21, 2018 - 16:30 to 19:00 Multiplex Gym (DND)


I. McMartin
Natural Resource Canada, Geological Survey of Canada

J.E. Campbell (Presenting)
Natural Resources Canada, Geological Survey of Canada

T. Tremblay
Canada-Nunavut Geoscience Office

P.X. Normandeau
Northwest Territories Geological Survey

P.-M. Godbout
Université du Québec à Montréal

A new glacial geomorphology map and database is in progress for the core region of the Keewatin Sector of the Laurentide Ice Sheet (LIS) in central mainland Nunavut and parts of eastern Northwest Territories. Keewatin is considered one of the last frontiers of the LIS where insufficient synthesized glacial histories restrict paleoglaciological reconstructions and glacial transport models, therefore hampering the effectiveness of surface mineral exploration methods. The new compilation will permit the identification and grouping of glacial features into coherent patterns, provide an update of the glacial history, and help evaluate glacial transport in areas of complex ice flow dynamics and changing basal ice thermal regimes. The map incorporates previous mapping (largely derived from air-photo interpretation with scattered fieldwork), recent field-based mapping compilations, and new interpretation using ArcticDEM and LANDSAT8 imagery. To constrain the chronology of glacial and deglacial events, and document the nature and composition of glacial sediments in selected glacial terrains, targeted fieldwork was completed in 2017 and 2018. The final product will consist of a map (scalable) and GIS database of glacial features and landforms (individually mapped), an interpretation of glacial landscapes (georeferenced overlays), a bibliography of all published sources, and a nomenclature of the map features.

A preliminary map for the eastern sector of the project area covering ~400,000 km2 in Nunavut is presented. The map comprises 43 complete/partial 1:250K scale NTS map sheets. Selected polygons, lines and point features of interest were extracted from a combined map geodatabase. The features were grouped into simplified shapefiles by theme. Information (metadata) is stored in attribute tables for each feature/field observation type regarding timing, mapper and nature of interpretation (e.g., error, duplication, shift, addition), and original data source. In total, 115,658 line features, 16,145 point features and 13,362 polygons are now included in the database, in addition to 5,753 ground and remote stations with field observations, ice-flow measurements and/or glacial sediment samples. This work is part of the Synthesis of Glacial History and Dynamics Rae Activity under the GEM-2 Program and is a collaboration between the Geological Survey of Canada, the Canada-Nunavut Geoscience Office and the Northwest Territories Geological Survey.