GEOSCAN, résultats de la recherche


TitreRemote predictive surficial materials and surficial geology mapping using LANDSAT 7, Hearne Lake, NTS 85I, NWT
AuteurStevens, C W; Kerr, D E; Eagles, S; Wolfe, S A
Source40th Annual Yellowknife Geoscience Forum, abstracts of talks and posters; par Watson, D M (éd.); Northwest Territories Geoscience Office, Yellowknife Geoscience Forum Abstracts Volume 2012, 2012 p. 69
LiensOnline - En ligne
Séries alt.Secteur des sciences de la Terre, Contribution externe 20120223
Réunion40th annual Yellowknife Geoscience Forum; Yellowknife; CA; Novembre 13-15, 2012
Documentpublication en série
ProvinceTerritoires du Nord-Ouest
Lat/Long OENS-114.0000 -112.0000 63.0000 62.0000
Sujetstélédétection; techniques de cartographie; géologie du substratum rocheux; dépôts glaciaires; géophysique; stratigraphie; géologie des dépôts meubles/géomorphologie; Cénozoïque; Quaternaire
ProgrammeBases de données couvrant les trois territoires (géologie de surface), GEM : La géocartographie de l'énergie et des minéraux
Résumé(disponible en anglais seulement)
Despite the relatively detailed knowledge of bedrock geology in the high mineral potential southern Slave 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 and other infrastructure, which are vital to northern economic development.
The preliminary remote predictive surficial sediment map for the Hearne Lake NTS Map Sheet 85I is derived using Landsat7 imagery (normalized bands 2,3,4,5 and 7). The spectral signatures associated with bedrock, silty clay, diamicton, sand and organic units were established using 'training areas' derived from traditional airphoto interpretation and limited 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 indicates silty clay infilling bedrock depressions and topographic lows between 157 m (current elevation of Great Slave Lake) and about 205 m asl. At elevations above 205 m, clay is less extensive, and isolated occurrences of diamicton in the form of reworked till veneer exist, as well as till blanket further inland. The high spatial density of silty clay generally below 205 m contributes to the reconstruction of glacial Lake McConnell (estimated maximum elevation of 280-300 m) and identifies the distribution of thaw-sensitive clay terrain. Both exposed and vegetated sand and gravel deposits, representing glaciofluvial sediments, and potentially useful as granular resources, were also identified across previously unmapped terrain.
Remote predictive sediment maps provide a first order assessment of surficial materials, which can guide traditional surficial geology 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. This preliminary version builds on the success of the predictive maps for the Yellowknife map sheet 85J (Geological Survey of Canada Open File 7108). Additional selected adjacent NTS sheets (85P, 85N) will integrate SPOT5 satellite imagery and topographic characteristics calculated from CDED data to improve mapping capabilities and accuracy.