Global sea-level change as a method of correlating the Late Permian coal measures in the Sydney, Gunnedah, and Bowen Basins, eastern Australia

Updated: 2018-04-20

Eustatic changes in sea level can be used to correlate sequences in widely separated areas. Thick terrestrial sequences with marine intercalations are especially suitable, provided the marine beds are not the result of tectonic subsidence. The method has been used to correlate Late Permian coal measures in the Sydney, Gunnedah, and Bowen Basins. The Dempsey Formation and its equivalents in the Sydney Basin, an unnamed correlative in the Gunnedah Basin, and the Black Alley Shale and MacMillan Formation in the Bowen Basin have been identified as being deposited during the same eustatic highstand, a result consistent with palynological conclusions. The Kulnura Marine Tongue (Sydney Basin) and the lower Burngrove Formation (Bowen Basin), on the other hand, owe their origin to tectonism. The correlations indicate that deposition of Late Permian coal measures began in the Bowen Basin later than in the Sydney and Gunnedah Basins, a conclusion that appears to be supported by marine macrofossil studies.