Kerogen showing complex

Figure 3. EPR spectra of three selected kerogens showing complex (atypical) spectra. Above each sample spectrum is a reference spectrum of the nitroxide standard (4-acetamido-2,2fi,6,-tetramethyl piperidine-1-i...

Comparable infrared (IR) spectra of complex organic solids such as coals (Fig. 7) 23), cherts, kerogens, humic substances and some natural polymers have been presented in various publications. They show a limited number of rather broad bands which are due to well defined chemical groups and can often be interpreted by comparison to less complicated spectra. The signals commonly observed in fossil organic matter are as follows (Robin et al., 1977 21), Tissot Welte, 1978 24), Rouxhet et al., 1980 22>, Friedel Carlson, 1972 25)) ... 

It is difficult to represent the complex structure of kerogen, but Fig. 4.17 attempts to show the various units present in type II kerogen at the start and towards the end of catagenesis.The elimination ofbulky peripheral substituents and the increasingly compact and aromatic nature of the residual kerogen with increasing maturity are apparent. The increase in aromaticity can be seen in Table 4.8. 

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