Geochemical exploration is any method of mineral or petroleum exploration that utilizes systematic measurements of one or more chemical properties of a naturally occurring material. The materials analyzed most commonly are rock, soil, stream and lake sediment, natural waters, vegetation and soil air. Ores of metals such as Cu, Ni and Au are the most common targets of geochemical exploration, but non-metallic commodities (diamonds, talc and fluorite) and deposits of oil and gas are also sought by geochemical exploration. This article discusses mainly techniques for metallic commodities; for specific coverage of methods directed toward petroleum

Many techniques of the old-time prospector, such as panning streams for gold, were rudimentary geochemical exploration methods, but systematic chemical surveys of soil and plants were initially attempted in Scandinavia and the USSR in the late 1930s and 1940s. Major application started in the 1950s, led by workers in the US, UK and the USSR. At present, geochemical methods are part of most major mineral exploration programs. In developed countries, where most ores exposed at the weathering surface have been discovered, the emphasis of modern exploration is on discovery of halo anomalies around blind orebodies, completely blind orebodies, or those covered by post-orerocks. Major references on geochemical exploration include Rose et al. (1979), Levinson (1980), and the series of Handbooks under the editorship of Govett (1981–1994).