DOM is the dominant form of organic matter in a number of the samples (Plate P12). Most of the material considered as DOM in this report comprises fragments ranging up to about 0.3 mm, too small to be handpicked. In the case of the present suite, the DOM has vitrinite as the major component. The DOM suites are typically vitrinite > liptinite > inertinite. The vitrinite in DOM generally consists of small particles of detrovitrinite. However, some occurrences of telovitrinite are present, as illustrated in Plate P13, figure 3 and figure 4. In these fields, the telovitrinite appears to represent root tissues, possibly from a root horizon of mangrove or Nypa-type vegetation.
Most of the liptinite consists of phytoplankton preserved as lamalginite. Tests are thin walled, and this maceral is generally rare. Some sporinite is also present. Cutinite is prominent in a restricted number of horizons. A high proportion of the cutinite is weakly fluorescing, as illustrated in Plate P13, figure 1, figure 2, figure 3, and figure 4. This could reflect derivation from tropical rainforests where thickened cuticles are relatively rare but could also be due to early diagenetic alteration. The cutinite illustrated in Plate P13, figure 1 and figure 2, is leaf derived and shows the characteristic serrate inner margins. Cutinite is relatively rare in marine sediment, and even within nonmarine sections is much less common in DOM compared with associated coals. The presence of well-preserved cutinite may indicate proximity to the source areas for the plant matter.