Title Surficial geology, Nogah Creek, British Columbia
Author Smith, I.R.
Source Open-File Report - Geological Survey of Canada, No.5306 1 disc. Publisher: Geological Survey of Canada, Calgary, AB, Canada
Publication Date 2009
Notes In English. Accessed on Aug. 12, 2011. 10 refs. GeoRef Acc. No: 309758
Index Terms alluvium; glacial geology; maps; Quaternary deposits; sediments; Canada-- British Columbia; British Columbia; Canada; Cenozoic; clastic sediments; colluvium; eolian features; fluvial features; glacial features; glacial geology maps; moraines; Nogah Creek; Quaternary; surficial geology; till; Western Canada
Abstract The Nogah Creek (NTS 94I/12) map sheet was inundated by the Laurentide Ice Sheet during the late Wisconsinan glaciation (ca. 25000-10000 years ago). Bedrock was not encountered during field operations anywhere in the map area, instead thick clay and fine- silt-rich till deposits appear to blanket almost the entire region. One particularly deep borrow pit exposed 24 m of till, suggesting that thrusting and stacking of till sheets is likely to have occurred. The remarkably flat topography, coupled with the relative impermeability of the regional till has led to surface ponding of water and the development of extensive organic fen and bog deposits. Given the impermeability of the till, much of the area is characterized by a perched aquifer at surface. Several borrow pits dug in such a manner as to prevent surface drainage from the surrounding peatlands into them were observed to remain dry, excepting that attributable to meteoric water accumulation, for two or more years. This suggests that the groundwater table is situated well below surface. Where peat has accumulated, it is likely underlain by permafrost, and probably contains significant amounts of ground ice as evidenced by extensive thermokarst and kettled topography.
URL http://apps1.gdr.nrcan.gc.ca/mirage/mirage_list_e.php?id=247301
Publication Type map
Record ID 65006354