2.0 Sources of Terrain and Surficial Geology Maps in British Columbia
An index to "surficial geology" maps of British Columbia has recently been prepared by Bobrowsky et a/. (1992). This useful compilation, which lists about 2000 maps, provides the basis for the following summary of agencies carrying out mapping and the types of maps available. It also includes a series of page-size maps of British Columbia showing areas covered by maps of various scales and published by various agencies, keyed to the NTS grid. References on Quaternary geology are well summarized in a useful bibliography by Clague (1987).
The above index lists maps under a variety of names, most of which refer to the information content of the maps (Table 1). Both terrain maps and surficial geology maps (as defined in Section 1.2) are listed as "surficial geology" maps because their information content is similar. The list includes both base data maps, which show the distribution of surficial materials, landforms and other geomorphic feature, and derivative maps (sometimes called interpretive maps) prepared by selecting information from the base data maps. Only base data maps are considered in Section 2.2.; derivative maps are discussed in Section 10.0. Addresses of agencies from which information about maps can be obtained and from which maps can be purchased are listed in Appendix H.
Most mapping of surficial materials (inventory mapping) has been carried out by the British Columbia Ministry of Environment, Lands and Parks (MELP; Table 2). MELP maps published after about 1975 are terrain maps; earlier maps are "soils and landforms" maps. Maps at a scale of 1:50,000 are available for most of the southern and central parts of the province; most of these are terrain maps, but some are soils and landforms maps. Terrain maps at smaller scales (1:100,000, 1:250,000) provide coverage in northwestern British Columbia, and maps at these scales elsewhere are mostly re-issues of maps originally produced at 1 :50,000. Larger scale maps, mostly at I :20,000 have been prepared for more densely populated areas such as the lower Fraser Valley, the Okanagan Valley, and parts of eastern Vancouver Island. Large scale mapping (1:20,000) has also been carried out for special projects, including assessment of terrain conditions for urban expansion near communities such as Invermere and Williams Lake.
MELP maps are reproduced as blackline prints that are run off from mylar masters when requested by users. Many maps are accompanied by reports which provide additional information about surficial materials, landforms, hazards such as avalanches and debris flows, and geological history.
Soil (pedological) maps (some are called "soils and landforms") issued by Agriculture Canada (AC) and MELP are based on terrain/surficial geology map units which are described in the soil map legend. Thus, information about surficial materials can be obtained from soil maps where terrain and surficial geology maps are not available. Map scales are most commonly 1:50,000 (MELP) and 1:100,000 (AC and MELP). Most soils maps are accompanied by reports which provide additional information about soils that is relevant to agriculture, forestry, and other forms of land use. Maps (mostly 1:100,000 scale) that accompany reports are off-set printed in several colours; other maps are available as blackline prints (Appendix H).
The more traditional geological agencies -- Geological Survey of Canada (GSC) and provincial Ministry of Energy, Mines and Petroleum Resources (MEMPR) -- have played a relatively minor, although significant, role in the mapping of surficial materials. GSC personnel map at scales ranging from 1 :50,000 to 1: 1 million and cover widely scattered parts of the province. Surficial geology maps produced by the GSC at 1:50,000 cover only a small part of British Columbia, (including the lower Fraser Valley and eastern Vancouver Island) and 1:100,000-scale maps, which are mostly terrain maps, also cover a limited area. Coverage at 1 :250,000 includes a few terrain maps and maps of glacial landforms. One to one million
scale terrain maps have been compiled for the southern part of the province, and glacial landforms are mapped at this scale for northeastern B.C.
Most mapping by the MEMPR has been oriented toward mineral exploration, and most maps are at a scale of 1:50,000. Map types include aggregate resources, surficial geology maps of areas with mineral potential, terrain maps of access routes to mineralized areas, and maps for placer resources. Surficial geology map production by MEMPR staff has increased significantly since the establishment of an Environmental Geology Section in 1988. MEMPR maps are reproduced as blackline prints, and most are accompanied by short reports. Terrain/surficial geology mapping for similar purposes has been carried out by some mining companies.
A large number of terrain maps, at scales ranging from 1:5000 to 1:50,000 have been produced under the auspices of the Ministry of Forests (MOF) and major forest companies. These maps are used for planning of forestry activities and identification of landslide-prone areas (Section 10.2). The provincial Ministry of Transportation and Highways (MoTH) has prepared many terrain maps for use in planning road locations (e.g., 1:50,000) and alignments (e.g., 1:10,000), for locating sources of aggregate (e.g., 1:20,000), and to define zones of hazard due to processes such as debris flows and avalanches.
Maps of terrain, surficial geology, landforms and other components of the physical environment relevant to various departmental jurisdictions have also been prepared by other governmental and private agencies such as Environment Canada, various Regional Districts of British Columbia, and B. C. Hydro and Power Authority.
A report of the status of terrain mapping programs, data bases, user groups, and user requirements in British Columbia was prepared by A. N. Boydell for the Surficial Geology Task Group in April, 1992. The report was based partly on discussions of the Task Group and partly on the results of a questionnaire sent to users of terrain maps and related information. Information about current mapping programs summarized from Boydell's report, is presented in Table 3.