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Proactive disclosure Print version   | |  Mercury concentrations in till, central British Columbia
Several mineralized occurrences of mercury have been found along Pinchi Fault, following the bedrock mapping by the Geological Survey of Canada (GSC), in the 1930's and 1940's. Two of the only three mercury mines in Canada have been developed along this fault (Takla Bralorne and Pinchi mines). A more recent regional survey of the surficial sediments undertaken by the GSC has demonstrated that mercury concentrations in till (a sediment type directly deposited by glaciers) are extremely high nearboth mines and are high at other localities along the Pinchi and Manson faults. The mercury in till is interpreted to be of detrital origin. In other words, during the last glaciation, glaciers advancing eastward, in the direction shown by the gray arrows, eroded bedrock and sediments enriched in mercury and transported the resulting debris in a "down-ice direction". This glaciological process resulted in areas with high mercury concentrations in till that extend up to twelve kilometres down-ice from their bedrock sources along Pinchi and Manson faults. Notice that the areal extent of mercury anomalies in till is several orders of magnitude greater than the extent of the mercury mineralization in bedrock which is confined to the faults. These observations have implications for mineral exploration as they are examples of the reworking of bedrock mineralization by glaciers which creates large anomalous zones in the till easier to detect than the confined mineralization in bedrock. Furthermore, they indicate that natural high mercury concentrations occur along Pinchi and Manson faults and that the mercury is derived from geological sources. Similar studies on metal distribution in glacial sediments, conducted elsewhere in Canada, constitute part of Terrain Sciences Division activities. More details can be found in the following references:
Plouffe, A.
Plouffe, A.
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