Characterization and quantification of groundwater sulfate sources at a mining site in an arid climate: The Monument Valley site in Arizona, USA.

Highlights: [•] Qualitative sulfate source ID using dual isotopes (34S and 18O) at a mining site. [•] Quantification of the sources (sulfide oxidation vs. sulfuric acid) by two methods. [•] Sulfate from sulfuric acid application served as the major source for 40years. [•] Proposed accumulation of sulfate salts formed from sulfuric acid in arid climate. [ABSTRACT FROM AUTHOR]