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TitreDiverse indicator mineral and geochemical dispersal plumes in till and esker samples: east arm of Great Slave Lake to the Thelon River, NT
AuteurKjarsgaard, B A; Knight, R; Sharpe, D; Cummings, D; Lesemann, J -E; Russell, H; Plourde, A; Kerr, D
Source2013 Yellowknife Geoscience Forum, abstracts; par Irwin, D; Northwest Territories Geoscience Office, Yellowknife Geoscience Forum Abstracts Volume 2013, 2013 p. 33-34
LiensOnline - En ligne
Séries alt.Secteur des sciences de la Terre, Contribution externe 20130423
ÉditeurNorthwest Territories Geoscience Office
Réunion2013 Yellowknife Geoscience Forum; Yellowknife; CA; Novembre 19-21, 2013
Documentpublication en série
ProvinceTerritoires du Nord-Ouest
SNRC75I; 75J; 75K; 75L; 75M; 75N; 75O; 75P
Lat/Long OENS-108.0000 -104.0000 64.0000 62.0000
Sujetstills; analyses de till; géochimie du till; dépôts glaciaires; eskers; méthodes d'exploration; prospection minière; dispersion des sédiments; profils de dispersion; géologie des dépôts meubles/géomorphologie; géochimie; Cénozoïque; Quaternaire
ProgrammeBases de données couvrant les trois territoires (géologie de surface), GEM : La géocartographie de l'énergie et des minéraux
ProgrammeDeveloppements methodologie, Initiative géoscientifique ciblée (IGC-4)
Résumé(disponible en anglais seulement)
We present results from till geochemistry and indicator mineral studies in surficial sediments from an extensive region (~36,000 km2 ) ofthe southeastern part of the Northwest Territories. This region encompasses parts of five distinct geological domains: southeast Slave, Taltson-Thelon magmatic tectonic zone, East Arm basin, Thelon basin, Rae domain (Queen Maud correlatives and Nonacho basin). Compilation of >500 known mineral occurrences suggests the following potential styles of mineralization: VMS, MVT, SEDEX, IOCG, lode gold, magmatic sulphide, vein copper, peralkaline syenite rare metal, granitic pegmatite rare metal, kimberlite-hosted diamond, 5-element vein, sandstone-hosted uranium, vein uranium, chromite. Due to the wide variety of deposit types, and thus a diverse suite of pathfinder elements, three different analytical procedures (aqua regia, 4-acid, fusion) were undertaken to provide a robust till geochemical survey. In conjunction a heavy mineral study was undertaken utilizing both till and esker samples. A number of diverse till geochemical anomalies are observed, including gold, silver, platinum, base metals, and Cr-Ni-Co. These geochemical anomalies are not always co-incident with, or correlate with the indicator mineral anomalies. Indicator mineral grains (and anomalous concentrations of these grains) recovered include gold, PGM's, chalcopyrite, gahnite, loellingite, arsenopyrite, chromite, olivine and low Cr-diopside. Importantly, all types of mineral grains were recovered from both till and esker samples. A significant, previously unknown plume of olivine + chromite + low Cr-diopside mineral grains and extends south-westward > 100 km downflow from a source area in the vicinity of Williams Lake where ultramafic and mafic boulders and cobbles are observed. In the Williams Lake area the till has high concentrations ofNi, Cr and Cu. To the west of the Thelon basin, previously unrecognized outliers of Thelon sandstone occur, based on till geochemistry (e.g. >90wt% Si02 and high Zr), which has potential importance for unconformity U mineralization.