Soil corrosion is a geologic hazard that affects buried metals and concrete that is in direct contact with soil or bedrock.  Metals are typically attacked by chloride solutions whereas high sulfate levels are harmful to concrete.  In western Colorado, the saline nature of the Mancos Shale with its abundant secondary sulfate mineralization (gypsum) is considered corrosive to both metals and concrete.  Chloride content, electrical resistivity, and pH level are indicators of the soil’s tendency to corrode ferrous metals.