LAUSR

Abstract This study experimentally examined the rates and stoichiometry of pyrite dissolution under low O2 conditions to obtain insights into the S and trace-metal cycles in the Precambrian. The pyrite dissolution experiments were conducted at ~10−7–0.21 atm of the partial pressure of O2 (PO2) in 1 mM HCl solutions at pH 3 and 23 ± 2 °C for ~10–40 days durations. The experiments were performed in a glove box to keep the low PO2 except for those at 0.21 atm which were conducted in ambient air. The rates of pyrite dissolution were determined as a function of PO2 based on the concentrations of total dissolved Fe. The rates at