Humic substances isolated from surface sediments: analytical characteristics

The elemental composition and infrared spectra of humic and fulvic acids isolated from Mid-Atlantic Continental Shelf and Slope surface sediments indicated relatively hydrogen-rich humic substance. The stable carbon isotopic ratios of the humic and fulvic acids range from -21.2 to -23.8 per mil with an average of -22.4 per mil. Pyrolysis-gas chromatographic patterns of humic acids and protokerogens showed longer carbon-chain length which are indicative of gas-condensate-to-oil prone, hydrogen-rich organic components. These humic substances are believed to be derived from a marine organic source and may be precursors in the formation of Type II kerogens. A succession of fulvic acid to humic acid to protokerogen is a possible evolutionary pathway for a portion of the protokerogens identified in this study.