In the 1930s, Soviet scientists pioneered the use of geochemistry to help find mineral deposits, and the idea quickly spread to other countries where the techniques were further developed. In the 1950s and 1960s, the Geological Survey of Canada was successfully conducting geochemical stream sediment surveys in areas of Canada not covered by the Canadian Shield.
Conducting stream surveys in the mineral-rich Canadian Shield proved to be a challenge owing to dense forest coverage, difficulty of access, and streams that were not well developed. Studies in Ontario, Quebec, and Newfoundland, however, demonstrated that many mineral deposits in lake catchment basins were reflected in the chemistry of centre-lake bottom sediments. In 1972, while working in Newfoundland, Survey geochemist Don Hornbrook developed the so-called Hornbrook Sampler, which could be deployed from a float-equipped helicopter, enabling the rapid sampling of forest lakes.
To date, this unique Canadian invention has been used to collect 100,000 lake sediments. The Hornbrook Sampler has permitted the geochemical mapping of some 1.5 million square kilometres of the Canadian Shield, and led to the discovery of gold in Saskatchewan and other significant mineral occurrences that may be developed as mines one day.
Garrett, R.G., Reimann, C., Smith, D.B., and Xie, X., 2008. From geochemical prospecting to international geochemical mapping: A historical overview; Geochemistry: Exploration, Environment, Analysis, v. 8, p. 205–217. doi:10.1144/1467-7873/08-174
Brummer, J.J., Gleeson, C.F., and Hansuld, J.A., 1987. A Historical Perspective of Exploration Geochemistry in Canada; in Geochemical Exploration 1985, (ed.) R.G. Garrett; Elsevier Scientific Publishing Company, Amsterdam, p. 1–39.
Davenport, P.H., Hornbrook, E.H.W., and Butler, A.J., 1974. 1975 Regional lake sediment geochemical survey for zinc mineralization in western Newfoundland; in Geochemical Exploration, (ed.) I.L. Elliott and W.K. Fletcher; Elsevier Scientific Publishing Company, Amsterdam, p. 555–578.