Developments in Economic Geology, 15: Geochemical Exploration 1980 focuses on practices, processes, methodologies, and principles involved in geochemical exploration. The selection first takes a look at the simultaneous determination of sulfide, polysulfides, and thiosulfate as an aid to ore exploration; hydrogeochemical exploration for uranium ore deposits; and mercury and mercury compounds in surface air, soil gas, soils, and rocks. Discussions focus on the methods of mercury analysis, calibration, sensitivity and computations, exploration, titration of hydrogen sulfide, polysulfides, thiosulfate and sulfite, and leaching of a sulfide deposit by percolating water. The book then examines meteorological noise in crustal gas emission and relevance to geochemical exploration; a mercury vapor survey in an area of thick transported overburden in Shanghai, China; and mechanisms of ore formation and primary dispersion at the Dexing porphyry copper deposit in Jiangxi and their implications to geochemical exploration. The publication explores the organic matter of a gulf coast well studied by a thermal analysis; selective extraction procedures applied to geochemical prospecting in an area contaminated by old mine workings; and application of radionuclide energy-dispersive X-ray fluorescence analysis in geochemical prospecting. The selection is a vital source of data for researchers interested in geochemical exploration.