“…Stream-sediment samples (<0.2-millimeter [mm] and <0.5-mm fractions) associated with sedex deposits in cold semiarid settings in northwestern Alaska contain anomalous concentrations of many metals, including as much as 10 milligrams per kilogram (mg/kg) Ag; tens of mg/kg As, Cd, and Sb; hundreds of mg/kg Cu and Ni; thousands of mg/kg Mn, Pb, and Zn; and hundreds of thousands of mg/kg Ba (Theobald and others, 1978;Kelley and others, 1992). Soil that overlies mineralized rock, such as at the Red Dog and Lik deposits in the Brooks Range, Alaska, contains hundreds to tens of thousands of mg/kg Pb, hundreds to thousands of mg/kg Ba and Zn, tens of mg/kg Ag, and tens to hundreds of mg/kg Cu, but concentrations of other metals, including less than 2 mg/kg Cd, hundreds of mg/kg Mn, and tens of mg/kg Ni, are low relative to stream-sediment abundances (Briggs and others, 1992;Meyer and Kurtak, 1992;Kelley and Kelley, 2003;Kelley and Hudson, 2007). Soil overlying sedex deposits in warm semiarid settings in Australia similarly contains hundreds to thousands of mg/kg Cu, Pb, and Zn and tens of mg/kg Ag (Cox and Curtis, 1977).…”