Identification_Information: Citation: Citation_Information: Originator: Smith, I.R. Publication_Date: 2009 Title: Gunnell Creek Edition: 1.0 Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: Open File Issue_Identification: 5305 Publication_Information: Publication_Place: Ottawa, Ontario Publisher: Geological Survey of Canada, Natural Resources Canada Other_Citation_Details: Recommended citation: Smith, I.R. 2009: Surficial geology, Gunnell Creek, British Columbia; Geological Survey of Canada, Open File 5305; British Columbia Ministry of Energy, Mines and Petroleum Resources, Map 2009-3, scale 1:50 000. Online_Linkage: Description: Abstract: The Gunnell Creek (NTS 94I/13) map sheet was inundated by the Laurentide Ice Sheet during the late Wisconsinan glaciation (ca. 25 000 - 10 000 years ago). A thick blanket of clay and fine-silt-rich till was deposited by westward flowing ice across the region. Observations of large shear structures in till (some demarcated by intra-till winnowed sand and gravel lenses and larger bodies), and prevalent clast pavements (including three distinct clast pavements in a single 10 m vertical section) suggest till in this area underwent extensive deformation, thrusting and stacking. This likely accounts for the considerable thicknesses of till (>3-10 m) seen here and elsewhere in the region. During deglaciation, the eastward retreat of ice appears to have undergone increasing degrees of topographic constraint. A regional full-glacial flow path curving west-northwest around the Etsho Plateau (to the north) and down the axis of the Sahtaneh River, eventually separated into two lobes. The point of divergence appears to have been a bedrock high situated ~20 km east of the map area. Ice in the northeastern quadrant of the map retreated first, and in an eastward fashion. The second lobe of ice which occupied much of the central and southern half of the map area, became increasingly lobate, and retreated in an east-northeast direction. Thick till deposits (Tb and Th) and prominent ice-marginal meltwater channels recorded in the southern areas of the map are associated with the retreat of this latter ice lobe. A prominent esker in the central part of the map area, paralleling the Sahtaneh River, was identified as part of this surficial geology study. At its proximal (eastern) end, it is up to 7m thick, declining to 2-4 m along the rest of its ~6 km length. The esker is bisected by the South Gunnell Road, and as such has locally been exploited as a source of gravel in support of road construction. Other smaller eskers situated north of here are predominantly composed of sand, offering little in the way of granular aggregate potential. Another esker identified from airphotographs in the southwestern corner of the map area has yet to be verified or its granular aggregate potential assessed by ground reconnaissance. Glaciofluvial terraces situated along Gunnell Creek and Sahtaneh River may also represent potential granular aggregate resources. Only those terraces situated on either side of the road crossing on Gunnell Creek have been inspected in the field, and these were predominantly found to be coarse sand deposits; the granular aggregate potential of other terraces in the map area remains to be assessed. Extensive crevasse-squeeze ridges and the hummocky character of till deposits in the map area are accentuated by bog and fen deposits that infill much of this flat to gently rolling terrain. Unique, long, linear (1-3 m high, 10-40 m wide), generally flat-topped ridges situated in the central part of the map area, paralleling the Sahtaneh River, are considered to be the product of longitudinal shearing in the ice and squeezing of till during full-glacial time. This may mark the separation of more dynamic ice flowing west-northwest around the Etsho Plateau from a more passive regional ice cover, akin to shear moraines and similar deposits associated with ice streams. Given their topographic expression and linear extent, these ridges make ideal corridors for road development. Purpose: Supplemental_Information: Data set is in English. Map is published in conjunction with the following organizations: British Columbia Miinistry of Energy, Mines and Petroleum Resources, Map 2006-3 Magnetic declination stated in degrees and minutes. Annual change stated in minutes. Magnetic declination at NW corner of map: 21°24'E, changing 22.6'W annually. Magnetic declination at SW corner of map: 21°18'E, changing 22.2'W annually. Magnetic declination at NE corner of map: 21°15'E, changing 22.6'W annually. Magnetic declination at SE corner of map: 21°9'E, changing 22.2'W annually. Magnetic declination at center of map: 21°17'E, changing 22.4'W annually. Number of base data sets used: 1 Base data set 1: Source is BC Watershed Atlas (TRIM base), ID is N/A, version N/A, N/A, scale 1:50000 Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2006 Range_of_Dates/Times: Beginning_Date: 2003 Ending_Date: 2006 Currentness_Reference: Field work years are 2003-2005. Compilation years are 2003-2006. Status: Progress: Complete Maintenance_and_Update_Frequency: None Planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -122.000 East_Bounding_Coordinate: -121.500 North_Bounding_Coordinate: 59.000 South_Bounding_Coordinate: 58.750 Data_Set_G-Polygon: Data_Set_G-Polygon_Outer_G-Ring: G-Ring_Point: G-Ring_Latitude: 59.0000 G-Ring_Longitude: -121.8492 G-Ring_Point: G-Ring_Latitude: 59 G-Ring_Longitude: -121.5000 G-Ring_Point: G-Ring_Latitude: 58.7500 G-Ring_Longitude: -121.5000 G-Ring_Point: G-Ring_Latitude: 58.7500 G-Ring_Longitude: -121.9070 G-Ring_Point: G-Ring_Latitude: 58.7500 G-Ring_Longitude: -122 G-Ring_Point: G-Ring_Latitude: 59.0000 G-Ring_Longitude: -122 G-Ring_Point: G-Ring_Latitude: 59.0000 G-Ring_Longitude: -121.8492 Keywords: Theme: Theme_Keyword: geoscientificInformation Theme_Keyword: Geological and geophysical Theme_Keyword: Surficial geology Theme_Keyword_Thesaurus: None Place: Place_Keyword: Sahtaneh River Place_Keyword: Chuatse Creek Place_Keyword: Moss Creek Place_Keyword: Gunnell Creek Place_Keyword: British Columbia Place_Keyword_Thesaurus: None Access_Constraints: None Use_Constraints: Her Majesty the Queen in Right of Canada 2009 For more information, please contact the Copyright Officer at the following address: ESS Copyright Officer Business Development Office Earth Sciences Sector 615 Booth St., Ottawa, Ontario K1A 0E9 Sa Majesté la Reine du chef du Canada 2009 Pour plus d'information, prière de communiquer avec le responsable du droit d'auteur à l'adresse suivante : Responsable du droit d'auteur du SST Bureau d'expansion des affaires Secteur des sciences de la Terre 615, rue Booth Ottawa (Ontario) K1A 0E9 Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Rod Smith Contact_Organization: Natural Resources Canada Contact_Address: Address_Type: Physical Address: 3303-33 Street North West City: Calgary State_or_Province: Alberta Postal_Code: T2L 2A7 Country: Canada Contact_Voice_Telephone: 403-292-7132 Contact_Facsimile_Telephone: 403-292-5377 Contact_Electronic_Mail_Address: rodsmith@nrcan.gc.ca Data_Set_Credit: Affiliated with British Columbia Ministry of Energy, Mines and Petroleum Resources. Digital cartography by Robertson, L. and Everett, E. 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