Till geochemical and indicator mineral methods in mineral exploration

This paper summarizes advances since 1987 in the application of glacial sed iment sampling to mineral exploration (drift prospecting) in areas affected by continental or alpine glaciation. In these exploration programs, elasti c glacial sediments are rested by geochemical or mineralogical methods to d etect dispersal trains of mineral deposit indicators that have been glacial ly transported from source by mechanical processes. in glaciated terrain th e key sampling medium, till, is produced by abrasion, crushing and blending of rock debris and recycled sediment followed by down-ice dispersal rangin g from a few metres to many kilometres. As a consequence of the mid-1980s b oom in gold exploration, the majority of case studies and regional till geo chemical surveys published in the past decade deal with this commodity. App roximately 30% of Canada and virtually all of Fennoscandia have been covere d by regional till geochemical surveys that aid mineral exploration and pro vide baseline data for environmental, agricultural, and landuse planning. T he most profound event in drift prospecting in the last decade, however, ha s been the early-1990s explosion in diamond exploration which has dramatica lly increased the profile of glacial geology and glacial sediment sampling and stimulated changes in sampling and analytical methods. (C) 2000 Elsevie r Science B.V. All rights reserved.