CHAPTER 2 • Marine Organic Geochemistry: A General Overview
syringealdehyde, acetosyringone and syringic acid divided by the total of vanillin,
acetovanillinone and vanillic acid, is zero for gymnosperm wood (Fig. 2.17) but >0 for
angiosperm wood. Likewise, a CIV ratio (p-coumaric + ferulic acids / the three vanillyl
phenols) discriminates woody and non-woody vascular plant tissues because only nonwoody tissues produce the cinnamyl phenols. These and related parameters have
gained wide use in two-dimensional plots to characterize mixtures of vascular plant
sources for sedimentary organic matter. For example, for a suite of plant tissues and
fresh water and marine sediments (Fig. 2.17; Gofti and Hedges 1992), a plot of monomeric [SIV1 M , against [CIV1 M shows wide discrimination between plant tissues and
sediment types. The lignin character of sediments indicates that gymnosperm tissues
are a major contributor to Dabob Bay and Washington shelf sediments, while a significant non-woody angiosperm tissue source is required to explain the ratios observed
for Long Lake and Crab Creek.
2.2.4.2
Lignin Dimers
Gas chromatographic analysis of CuO oxidation products reveals, in addition to the
commonly used eight lignin monomers, the presence of additional monomers and a
complex series of phenolic dimers (Fig. 2.18) (Gofti and Hedges 1992). These diphenolie products reflect the ultrastructure of the lignin polymer and have no other origin,
in contrast to phenolic acids linked to polysaccharides via ester links that are hydrolyFig. 2.18. Structures of major
dimeric phenols produced by
CuO oxidation of lignin
5',5' dimers
H3C~O OOQOCH3
O 11110
HO
CC
OH
R'
R
/3, l-diketone dimers
a, l-monoketone dimers
R'
a,5-monoketone dimers
a,2-methyl dimers
syringealdehyde, acetosyringone and syringic acid divided by the total of vanillin,
acetovanillinone and vanillic acid, is zero for gymnosperm wood (Fig. 2.17) but >0 for
angiosperm wood. Likewise, a CIV ratio (p-coumaric + ferulic acids / the three vanillyl
phenols) discriminates woody and non-woody vascular plant tissues because only nonwoody tissues produce the cinnamyl phenols. These and related parameters have
gained wide use in two-dimensional plots to characterize mixtures of vascular plant
sources for sedimentary organic matter. For example, for a suite of plant tissues and
fresh water and marine sediments (Fig. 2.17; Gofti and Hedges 1992), a plot of monomeric [SIV1 M , against [CIV1 M shows wide discrimination between plant tissues and
sediment types. The lignin character of sediments indicates that gymnosperm tissues
are a major contributor to Dabob Bay and Washington shelf sediments, while a significant non-woody angiosperm tissue source is required to explain the ratios observed
for Long Lake and Crab Creek.
2.2.4.2
Lignin Dimers
Gas chromatographic analysis of CuO oxidation products reveals, in addition to the
commonly used eight lignin monomers, the presence of additional monomers and a
complex series of phenolic dimers (Fig. 2.18) (Gofti and Hedges 1992). These diphenolie products reflect the ultrastructure of the lignin polymer and have no other origin,
in contrast to phenolic acids linked to polysaccharides via ester links that are hydrolyFig. 2.18. Structures of major
dimeric phenols produced by
CuO oxidation of lignin
5',5' dimers
H3C~O OOQOCH3
O 11110
HO
CC
OH
R'
R
/3, l-diketone dimers
a, l-monoketone dimers
R'
a,5-monoketone dimers
a,2-methyl dimers