Sulfur in peat-forming systems of the Okefenokee Swamp and Florida Everglades: origins of sulfur in coal

Abstract

Six sulfur forms were investigated in profiles of freshwater- and marine-derived peat-forming systems of the Okefenokee Swamp, Georgia and Everglades Swamp, Florida. Total sulfur levels of 0.1–10% were found, thus indicating a major incorporation of sulfur in the very early stages of coal formation. The quantities of hydrogen sulfide and elemental sulfur observed appeared to be indicative of whether marine or freshwater conditions prevailed at the site of deposition. Carbon-bonded sulfur accounted for 70% of the total sulfur in the freshwater peat and 50% of the total sulfur in the marine peat. Over 15% of the total sulfur was in pyritic combination in the marine environment, while levels of pyrite in the freshwater peats were an order of magnitude lower. An ester-sulfate fraction represented 25% of the total sulfur in both freshwater and marine peats. The levels of sulfur forms in the peat profiles are compared to those observed in living plants and to various coals; levels of pyrite and organic sulfur in the peat are similar to those found by other investigators in freshwater-derived and marine-derived coals.