Till geochemistry surveys are targeted at regions of high mineral potential where glacial sediments cover and obscure the underlying bedrock. These surveys are conducted in conjunction with surficial geology mapping.
Till geochemical anomalies identify areas where glaciers eroded mineralized bedrock and redeposited the mineral debris in down-ice dispersal trains. As glacial dispersal trains may be hundreds to thousands of times larger in area than their original bedrock source, they provide a cost effective target for mineral exploration programs in drift-covered terrains. In addition, tills as 'first-derivative' products of bedrock are more readily traced to source than higher order derivatives such as glaciofluvial or glaciolacustrine sediments. Even so, geochemical exploration programs in drift-covered regions must rely on an understanding of glacial processes and the glacial history of the area, especially where the dispersal train may be diffuse or irregularly shaped.
An index of base and precious metal regional- to property-scale subglacial till geochemical and mineralogical surveys in British Columbia, BCGS Open File 2016-2 (updated August 2017)
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Collecting till sediment samples