The distribution of sulfur and organic matter in various fractions of peat origins of sulfur in coal
Casagrande, D.J.; Gronli, K.; Sutton, N.
Geochimica et Cosmochimica Acta 44(1): 25-32
The peat-forming systems of the Okefenokee Swamp [Georgia, USA] are viewed as modern progenitors of coal. Taxodium and Nymphaea-derived peat-forming systems were characterized in terms of organic fractions and the distribution of organic/inorganic S in each organic fraction (water soluble, benzene/methanol soluble, humin, humic acid, fulvic acid). The humin fraction is the largest organic fraction in both environments, approaching 70% of the total organic matter in the Nymphaea-derived environment. Humin origins are discussed in terms of a humic acid precursor and undecomposed plant material. Each depth of peat apparently represents a diagenetic history of events apparently occurring primarily when the currently buried peat was at the surface. The S content of both peat-forming areas is low (0.23-0.27%); organic S is the dominant S form. Humin contains 50-80% of the total sulfur and of this, 80% is organic S. Ester-sulfate appears to be especially prevalent in the fulvic acid fraction. The S content of freshwater-derived peats is similar in quantity and distribution to that found in lower sulfur coals.