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TitleQuaternary geology of the Fort Fraser and Manson River map areas, central British Columbia
AuthorPlouffe, A
SourceGeological Survey of Canada, Bulletin 554, 2000, 62 pages (4 sheets), (Open Access)
LinksCanadian Database of Geochemical Surveys, downloadable files
LinksBanque de données de levés géochimiques du Canada, fichiers téléchargeables
PublisherNatural Resources Canada
MapsPublication contains 3 maps
Map Info.surficial geology, landforms, lithological, 1:250,000
Map Info.surficial geology, glacial deposits, 1:750,000
Mediapaper; on-line; digital
RelatedThis publication contains the following publications
File formatpdf
ProvinceBritish Columbia
NTS93K; 93N
AreaFort Fraser; Manson River; Omineca Mountains; Nechako Plateau; Fraser Basin; Trembleur Lake; Babine Lake; Endako River; Burns Lake; Omineca River; Chuchi Lake; Tchentlo Lake; Stuart Lake; Fraser Lake; Pinchi Lake; Tezzeron Lake
Lat/Long WENS-126.0000 -124.0000 56.0000 54.0000
Subjectssurficial geology/geomorphology; geochemistry; geochronology; stratigraphy; glacial deposits; gold; sands; gravels; Wisconsinian glacial stage; glacial history; glacial features; climatic fluctuations; paleoclimates; glaciation; glacial lakes; deglaciation; tills; glaciofluvial deposits; glaciolacustrine deposits; colluvial deposits; alluvial deposits; landforms; drumlins; eskers; kettles; landslides; dunes; moraines; glacial striations; stratigraphic analyses; till geochemistry; Holocene; aggregates; radiocarbon dates; faults; Fraser Glaciation; Olympia Interglacial Stage; Quaternary
Illustrationssketch maps; rose diagrams; photographs; geochemical analyses; stratigraphic columns
Released2000 09 01; 2013 09 10
AbstractThe Fort Fraser and Manson River map areas were last glaciated during the Late Wisconsinan Fraser Glaciation. Quaternary sediments predating this event are rare. The oldest deposits identified are oxidized sand and gravel, which locally contain placer gold. Stratigraphic evidence of a pre-Fraser glaciation was found at one site. Sediments of the Olympia Nonglacial Interval have been identified at three sites. Paleoecological reconstruction indicates climatic conditions cooler than at present for at least part of that nonglacial interval.
The mountainous regions were the first to be glaciated at the onset of Fraser Glaciation. Valley glaciers advanced from three major accumulation centres: the Skeena, Coast, and Cariboo mountains. In easterly draining valleys, sand and gravel accumulated on outwash plains in front of advancing glaciers. In most westerly draining valleys, the drainage was blocked by advancing ice and glacial lakes were formed. The pattern of ice advance was reconstructed primarily from crosscutting relationships of glacial erosion marks measured on bedrock outcrops. Ice from the Coast and Skeena mountains generally flowed easterly, but was deflected to the north and northeast in the eastern part of the study area, where it coalesced with an ice lobe derived from the Cariboo Mountains. Deglaciation proceeded from east to west along an irregular front controlled by topography. Numerous glacial lakes developed behind decaying ice. Postglacial sediments include colluvium, alluvium, organic, eolian, and anthropogenic deposits. Postglacial aggradation in valleys was followed by incision of valley fills and establishment of the modern drainage.