Sequence stratigraphic analysis and the origins of Tertiary brown coal lithotypes, Latrobe Valley, Gippsland Basin, Australia

The methods of sequence analysis have been applied to the onshore Gippsland Basin and in particular to the Latrobe Valley Group coal measures which include up to five coal seams each exceeding 100 m in thickness. The methods appear to provide new depositional concepts to the evolution of these seams, and the development of coal lithotypes. In the eastern half of the Latrobe Valley evidence for marine transgressions into the coal measures are recorded in most of the interseam sediment splits by the presence of contained foraminifera and dinoflagellates. To the west (inland) these splits pinch out into continuous coal. However, they can be followed westwards as enhanced organic sulphur levels along sharply defined boundaries between light coal lithotypes below and dark coal lithotypes above. The dark lithotype immediately overlying each of these boundaries contains the highest sulphur value and warmer climate pollen assemblages (Sluiter et al., 1995, this volume).