GEOSCAN, résultats de la recherche


TitreGEM Mackenzie Project: Preliminary surficial geology map, Wecho River, NTS 85-O, NWT
AuteurMorse, P D; Kerr, D E; Wolfe, S A
Source43rd Annual Yellowknife Geoscience Forum - Program and Abstracts; Northwest Territories Geoscience Office, Yellowknife Geoscience Forum Abstracts Volume (2015), 2015.
Séries alt.Secteur des sciences de la Terre, Contribution externe 20150316
Réunion43rd Annual Yellowknife Geoscience Forum; Yellowknife; CA; Novembre 24-26, 2015
Documentpublication en série
Mediapapier; en ligne; numérique
ProvinceTerritoires du Nord-Ouest
Lat/Long OENS-116.0000 -114.0000 64.0000 63.0000
Sujetslevés géologiques; recherche géologique; géologie du substratum rocheux; tills; eskers; dépôts glaciolacustres; dépôts organiques; Lac glaciaire de McConnell; Géologie des dépôts meubles; géologie générale; géologie des dépôts meubles/géomorphologie
ProgrammeBouclier à Selwyn du corridor de Mackenzie, GEM2 : La géocartographie de l'énergie et des minéraux
Résumé(disponible en anglais seulement)
The Geo-mapping for Energy and Minerals (GEM) program of Natural Resources Canada provides a foundation for sustainable economic development in the North, and the Mackenzie Corridor region of interest represents the largest unmapped (bedrock and surficial geology) area of Northwest Territories. The goal of predictive surficial geology mapping is to develop timely first-version regional maps, validated in selected areas and reviewed by geological experts, which reasonably depict the distribution of basic or generalized surficial sediments, filling major knowledge gaps for northern industry exploration and development purposes.
The Wecho River map (NTS 85-O) identifies surficial geology and associated landforms resulting from the last glaciation (Wisconsinan), and from inundation about 13 000 cal BP by glacial Lake McConnell at the margin of the retreating Laurentide Ice Sheet. With continued falling lake levels due to differential isostatic uplift, the lake first separated from the Great Bear basin, and remained in existence until about 9500 cal BP, when the basins of Great Slave and Athabasca lakes separated. The resulting ancestral Great Slave Lake continued to decline, towards its present elevation of 156 m asl, constrained by the Mackenzie River outlet at Fort Providence.
This preliminary map of surficial geology is based on remote predictive mapping (RPM), airphoto interpretation and fieldwork. The RPM methodology adopted for mapping NTS 85-O was based on the availability of remote sensing data and the authors¿ field experience of surficial materials and geology found in the region. The technique builds upon experience gained in previous surficial RPM activities in adjoining areas, 85-I, 85-J, 85-N, and 85-P. Preliminary results show that bedrock predominates in the land area throughout the map (69.7% of map area) and till veneer deposits become more prevalent in the northeast (12.6%). Undifferentiated till (1.1%) deposits, though limited in extent, are more common in the northwest. Glaciofluvial esker complexes generally form linear deposits trending southwest, and vary in extent (2.1%). Glaciolacustrine sediments (12.9%) are common in some lake and river drainage basin valleys up to 250 m elevation or more where they are fine-grained, whereas coarser-grained glaciolacustrine beaches and deltas occur as high as 330-350 m in the northeast, likely defining the eastern limit of glacial Lake McConnell. Remaining land area is comprised of wet organic deposits (1.5%) distributed throughout the map sheet. Results from 100 cross-validations using 75% randomly sampled data for training and the remaining 25% for validation indicate and average overall accuracy of the training areas of >97%. However, based upon comparison of mapping results with extensive field survey data, several glaciofluvial deposits were confused with bedrock. The final iteration of the map will involve some manual reclassification of the glaciofluvial class. Future work in 2016 will be the production of predictive surficial geology maps at 1:250,000 scale for NTS 85-O and NTS 85-K in the Canadian Geoscience Map (CGM) format.
Résumé(Résumé en langage clair et simple, non publié)
La géologie des formations superficielles de la rivière Wecho (SNRC 85-O) a été répertorié comme une partie du programme de géocartographie de l'énergie et des minéraux (GEM) de Ressources naturelles Canada. La carte préliminaire, basée sur la cartographie prévisionnelle à distance (RPM), interprétation de photos aériennes et sur travaux de terrain, identifie la géologie des formations superficielles résultant de la dernière glaciation (Wisconsinien), et de l'inondation par lac proglaciaire McConnell (13 000 cal BP) jusqu'au niveau actuel du Grand lac des Esclaves, en raison du relèvement de la croûte. La roche en place domine le paysage (69,7%), avec un placage de till (12,6%) au nord, des sédiments glacio-lacustres (12,9%) au sud et au sud-ouest, et avec des dépôts fluvioglaciaires (2,1%), du till indifférencié (1,1%) et dépôts organiques (1,5%) distribués à travers la région. La dernière itération d'une carte de la géologie de surface prédictive sera produite en 2016, à échelle 1: 250,000 pour SNRC 85-O dans le format Carte géoscientifique du Canada (CGM).