|Title||Surficial materials mapping using Landsat7 and topographic CDED data, Yellowknife NTS map sheet 85J, NWT|
|Author||Stevens, C W; Kerr, D E; Wolfe, S A; Schwarz, S|
|Source||39th Annual Yellowknife Geoscience Forum, abstracts of talks and posters; by Fischer, B J; Watson, D M; Northwest Territories Geoscience Office, Yellowknife Geoscience Forum Abstracts Volume vol. 2011,
2011 p. 121 (Open Access)|
|Links||Online - En ligne|
|Alt Series||Earth Sciences Sector, Contribution Series 20110251|
|Meeting||Yellowknife Geoscience Forum; Yellowknife; CA; November 15-17, 2011|
|Lat/Long WENS||-116.0000 -114.0000 69.0000 68.0000|
|Subjects||surficial geology/geomorphology; Nature and Environment; glacial deposits; glacial features; remote sensing; mapping techniques; computer mapping; satellite imagery; topography; Landsat7|
|Program||Climate Change Geoscience, Program Management - Climate Change Science|
|Abstract||Despite the relatively detailed knowledge of bedrock geology in the mineral-rich Yellowknife region, knowledge of surficial sediments, permafrost, land cover, and geotechnical conditions is still
rudimentary. This lack of basic geoscience information hinders the understanding of present and future terrain risks to roads, airports and other infrastructure, which are vital to northern economic development.|
We have derived a preliminary
remote predictive surficial materials map for the Yellowknife NTS Map Sheet 85J using Landsat7 imagery (normalized bands 2,3,4,5 and 7 at 30 m spatial resolution) and 1:50 000 scale Canadian Digital Elevation Data (CDED). The spectral signatures
associated with bedrock, clay, sand and organic units were established using ¿training areas¿ derived from traditional airphoto interpretation and field validation data. A high level of statistical separation between the training areas indicates that
spectral differences exist for each surficial unit and a reasonable model can be built to map this region.
The preliminary map, focusing initially on the area north of the North Arm, Great Slave Lake, indicates widespread clay infilling bedrock
depressions and topographic lows between 157 m (current elevation of Great Slave Lake) and 200 m asl. At elevations above 200 m, clay is less extensive and isolated occurrences of coarse-grained sediment (sand and gravel) in the form of reworked
eskers and beach deposits exist. The high spatial density of clay generally below 200 m contributes to the understanding of former Glacial Lake McConnell (estimated maximum lake elevation of 280 m) and identifies the distribution of thaw-sensitive
clay terrain. Exposed and vegetated sand and gravel deposits, potentially useful as granular resources, were also identified across previously unmapped terrain.
Remote predictive maps provide a first order assessment of surficial materials, which
can guide traditional mapping efforts and offer regional information for geological interpretations and decision making processes related to infrastructure. From these maps, together with field data, predictive surficial geology maps can be derived
as an aid to mineral exploration. Future versions of the Yellowknife map sheet 85J and surrounding NTS sheets (e.g. 85I, 85O, 85P, 86A, 76D and 75L) will integrate Landsat7 imagery, SPOT5 imagery and topographic characteristics calculated from CDED
data to improve mapping capabilities and accuracy.