T129 Geologic Maps and Their Derivatives (Posters)

Wednesday, 28 October 2020
10:00 AM - 12:00 PM
Meeting Rooms

HIGH-RESOLUTION MAPPING OF GLACIAL LANDSCAPES IN CENTRAL MAINLAND NUNAVUT USING ARCTICDEM DATA AND LANDSAT 8 IMAGERY

Paper number: T129-3
Program: Technical Sessions
Time: 10:20 AM – 10:30 AM

Authors

Abstract

A new glacial geomorphology map was produced for an area covering ~415,000 km2 in a core region of the Laurentide Ice Sheet (LIS) in Nunavut. The map builds on recent and legacy surficial geology maps and is significantly improved by digitization of glacigenic features using a combination of high-resolution ArcticDEM data (2-m resampled to 5-m resolution) and Landsat 8 images (30-m pansharpen to 15-m). Data comprised of glacial geomorphological features were individually identified (lines and points) or grouped in generalized areas (polygons). Information (metadata) was stored in attribute tables for each mapped feature, including feature type, subtype (if distinguished), and original map data source and/or nature of modification or addition.

From this unprecedented, detailed inventory of ~152,000 features and >14,000 field observations, we identify and map coherent patterns of landform development (landsystems) between the Manitoba border and the Arctic coast, many of which are entirely new and others that are significantly modified or updated. In particular, we recognize six separate ice streams and delineate numerous palimpsest streamlined landscapes with associated ice flow trends and relative ages. A continuum of relict terrains with varying basal ice thermal conditions is mapped for the first time in the ice divide migration zone between Baker Lake and Wager Bay. In addition, deglacial cold-based retreat terrains and preserved warm-based landscapes unaffected by younger glacial events have been identified.

The final products consist of: generalized glacial geomorphology maps at 1:5 million and 1:1 million scales; an interpretation of entirely new or updated glacial landsystems; and a bibliography of all published sources of information. The GIS data files comprise glacial features mapped at original scales, standardized field datasets and glacial landsystems overlays. These new georeferenced, multi-scale datasets provide a comprehensive framework to strengthen reconstructions of the glacial history and dynamics of one of the largest ice dome of the LIS, help identify distinct glacial sediment transport paths for applications to mineral exploration, and test numerical modelling of the LIS in support of climate change studies and long-term evolution of modern ice sheets.

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-354703

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