SURFICIAL DEPOSITS IN THE LOUIS CREEK AND CHU CHUA CREEK AREA
Surficial geological mapping and drift exploration studies were undertaken in the summer of 1997 north of Kamloops in NTS map sheets 92Pil (Louis Creek) and 92P18 (Chu Chua Creek), as a continuation of the Eagle Bay Project initiated in the previous year (Bohrowsky et al., 1997; Dixon-Warren er al., 1997). The surticial component is pat of an integrated regional study centred on Devono-Mississippian rocks of the Eagle Bay Assemblage and Permian to Devonian rocks of the Fennell Formation. Massive sulphide deposits hosted in stratiform volcanogenic assemblages of the Fennell Formation at Chu Chua (MINFILE 092P 140) and syngenetic sedimentary rocks of the Eagle Bay Assemblage at Mount Armour (MINFILE 092P 051) suggest the region has considerable mineral potential. Polymetallic gold-bearing veins hosted in volcanic and volcanogenic rocks of the Fennel Formation at Windpass (MINFILE 092P 039) also suggest a high potential for gold in the area. Several placer occurrences of Au have also been recorded in the region.
Geological Survey of Canada's contributions to understanding the composition of glacial sediments
Drift compositional studies were initiated at the Geological Survey of Canada (GSC) in the mid-1960's in projects that drew heavily on the technology and approaches developed in Fennoscandia over the previous century. As this research progressed and expanded in the 1970's, its Fennoscandian character diminished and, like the geochemical exploration research program that it closely paralleled, drift prospecting began to acquire a distinctly Canadian character, imposed by the geographical and logistical constraints of climate and asymmetric population distribution. GSC research has increasingly focused on understanding and explaining the geochemical expression of the mineralogical composition of glacial sediments that are unaltered or only slightly altered by postdepositional weathering. Because glacial sediments are generated largely by crushing and abrasion, their various mineral and lithological components attain characteristic size modes based on physical properties such as cleavage and hardness. This s...
Till geochemistry in Finland and Canada
Abstract Glacial geology has been much more thoroughly integrated into mineral exploration programs in Finland than in Canada. In Finland, the compositional properties of glacial sediments are utilized to find buried ore, whereas in Canada glacial deposits have been regarded more often than not as a hindrance to exploration. The application to mineral exploration of the latest theories on ice-sheet dynamics, sedimentation from ice, and till composition is presently regarded as somewhat more important in Canada than in Finland. Three specific geochemical aspects of till have been investigated recently by the author and should have considerable relevance to techniques of exploration: 1. (1) Mineral and chemical partitioning in till is marked because of the tendency of minerals to crush to certain specific sizes during glacial comminution. For most metals investigated, highest concentrations are in the clay-sized fraction, presumably held within the structure of phyllosilicates or scavenged by secondary oxides, both of which phases occur preferentially among particles finer than about 10 μm. 2. (2) The more labile ore minerals, such as sulphides, are destroyed by weathering to depths several metres below the postglacial solum. This destruction is often accompanied by a concomitant increase in metal concentration in the clay-sized ( μ m) fraction. 3. (3) A till sample is a composite of compositions inherited from over-lapping dispersal trains at several different scales. The sizes of trains range from continental scale, covering tens of thousands square kilometres, to local scale which can be mapped for distances of no more than a few hundred metres. It is essential in mineral exploration to be able to differentiate between the rare, but sometimes distinctive or easily concentrated clasts from far away and those that might have been generated by a small, but economic, local source.