The climate was very different on the landmasses of Gondwana, which extended through high southern latitudes towards the South Pole. There, the climate was cold and in some places glacial. Permian Gondwanan coal in Australia, India and South Africa formed in these very different, cold-climate situations. A chain of volcanoes along eastern Australia erupted intermittently for over 60 Ma, and the last orogeny affecting Australia built a mountain chain at its eastern margin.

THE SETTING AND RELATIONSHIPS

Through the Carboniferous and Permian interval (359–252 Ma), Australia formed the northeastern part and margin of Gondwana, the Southern Hemisphere sector of an even larger continental aggregation: Pangea. To the south lay Antarctica, to the southwest India; all contributed parts of an ancient continental interior. The crust of the Australian continent was more extensive than at present in its northwestern part, between Darwin and Exmouth Gulf. Fragmentation occurred there by rifting and seafloor spreading, which commenced as early as the Permian and continued into the Jurassic. Detached pieces of continental crust were transported northwards, eventually colliding with, and becoming part of, Southeast Asia. During the Carboniferous to Permian interval Australia moved progressively into a high southern latitude, lying between approximately 40 and 70° at the beginning of the Permian.

An ocean edge extended from Tasmania to east of Cape York, in far northern Queensland. The long-established convergent plate boundary to the east of Australia continued to strongly influence the setting of the continental margin. Plate boundary advance in the mid Carboniferous induced mountain building, and the sedimentary record for this period is poor. However, plate boundary retreat towards the close of the Carboniferous and into the early Permian induced widespread extension of the eastern Australian crust. A major episode of sedimentary basin formation was the consequence, most notable in the development of the Sydney-Bowen Basin, which is a striking feature of eastern Australian geology (see Figure 7.14). Infill of these features contains a rich sedimentary record of glacial association.