|Résumé||(disponible en anglais seulement)|
Government geochemical data are independent impartial datasets that reduce risk for decision makers in mineral exploration, environmental assessment, urban
planning, protected area selection, agriculture or public health. In Canada, the initiation of large?scale centre?lake and stream sediment surveys in the 1970s is an early example of government recognising the need for geochemical data. Since then,
more than 110,000 lake and 90,000 stream sediment samples have been collected by Canadian government agencies as a cost effective means of assessing regional scale mineral potential. Geochemical surveys in Canada additionally employ till, soil, and
vegetation. Canadian exploration successes directly related to government geochemical surveys include the discoveries of the Kudz Ze Kayah, Star Lake and Brewery Creek deposits and, more recently, the Rainy River gold deposit. Stream sediment surveys
have facilitated protected areas decision making, including the identification of high mineral potential in the South Nahanni River area. Governments use geochemical surveys to identify areas at risk due to natural or anthropogenic contamination.
Recent surveys in southern Ontario have identified groundwater contaminated by historic gas production and areas with natural fluoride contents that exceed the drinking water criteria. On the Canadian Prairies, elevated contents of cadmium in wheat
indicate natural contents in soil and bedrock. Since the explosion in diamond exploration activity and discoveries in northern Canada in the 1990s, indicator minerals have become an important part of government geochemical surveys supporting mineral
exploration. Government agencies have helped adapt diamond indicator mineral methods for exploration for magmatic Ni?Cu?PGE, VMS, IOCG, MVT and intrusion?hosted Cu, Mo and W deposits. The Canadian Geochemical Surveys website is an example of how
large volumes of geochemical data for different media, analytical methods and government jurisdictions can be linked and delivered to the public using modern web?based tools, including plotting data as KML files in Google EarthTM.