THERMOCHEMICAL REDUCTION AND SULFUR ISOTOPIC BEHAVIOR OF SULFATE BY ACETIC-ACID IN THE PRESENCE OF NATIVE SULFUR

Reaction between sodium sulfate and acetic acid under hydrothermal con ditions has been investigated in order to demonstrate the thermochemic al reduction of seawater sulfate by organic matter at moderate tempera tures during diagenesis Although no reduction of sodium sulfate occurr ed directly, the sulfate was reduced by acetic acid to hydrogen sulfid e in the presence of native sulfur over the temperature range of 200-2 70-degrees-C. The sulfur isotopic behavior of sulfur compounds suggest s that the isotope fractionations are not controlled by kinetic isotop e effects but rather by the isotope exchange reaction between the sulf ate and sulfide.