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TitleSedimentology of the Archean Yellowknife Supergroup at Yellowknife, District of Mackenzie
AuthorHenderson, J B
SourceGeological Survey of Canada, Bulletin 246, 1975, 62 pages,
PublisherGeological Survey of Canada
Mediapaper; on-line; digital
File formatpdf
ProvinceNorthwest Territories
AreaYellowknife; District of Mackenzie
Lat/Long WENS-114.5000 -114.1667 62.6667 62.3333
Subjectsregional geology; tectonics; sedimentology; chemical analyses; bedrock geology; faults, thrust; greywackes; lithology; modal analyses; paleocurrents; pebble counts; provenance; turbidites; archean; Banting Formation; Burwash Formation; Duck Formation; Jackson Lake Formation; Kam Formation; Slave Province; Walsh Formation; Yellowknife Supergroup; Precambrian
Illustrationsrose diagrams
Released1976 02 01; 2015 12 17
AbstractAt Yellowknife the Jackson Lake and Burwash Formations of the Yellowknife Supergroup represent contrasting sedimentary environments at the margin of an Archean basin in the Slave Structural Province. The Jackson Lake Formation, exposed on the west s ide of Yellowknife Bay, consists of a local discontinuous basal conglomerate derived largely from the thick mafic volcanic sequence that it unconformably overlies. The remainder of the formation consists of approximately 1, OOO feet ( 300 metres) of cross bedded felsic volcanic lithic wackes with minor thin beds or lenses of conglomerate also largely of silicic volcanic derivation. The formation is a terrestrial braided river deposit that is considered to be the basin margin equivalent of the Burwash Formation that occupies the main part of the basin. The Burwash Formation, exposed on the east s ide of Yellowknife Bay, consists of approximately 15, OOO feet (4, 500 metres) of interbedded greywackes and mudstones and shows many of the features characteristic of turbidites. Analysis of the sedimentary structures indicate that the turbidites were derived from the west, possibly from an area occupied by an extensive granitic terrain, and accumulated in depositional fan valleys on a submarine fan complex near the margin of a large sedimentary bas in. The high percentage of dominantly felsic volcanic rock fragments, together with abundant quartz and feldspar, and minor but ubiquitous granitic rock fragments in the greywackes, indicates a mixed silicic volcanic and granitic provenance. The modal and chemical composition and volumetric abundance of these sediments indicates an extensive sialic crust prior to the accumulation of the Yellowknife Supergroup at Yellowknife.