The Carboniferous period is so named because of the extensive carbon-bearing coal deposits formed at that time in Europe and North America. The Northern Hemisphere climate was tropical, with vast coastal peat swamps and reefal limestones forming offshore. The Permian continued to be hot, with seasonal river systems and large salt lakes in North America and Europe.

The climate was very different for the landmasses of Gondwana, locked near the South Pole. There the climate was cold, and in some places glacial. Permian Gondwana coals 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 20 million years.

A GLACIATED CONTINENT

The Australian landmass was glacial and actively volcanic – almost the complete opposite of the hot and dormant continent of today. A possible analogue is the continental mass of cold–climate Alaska, bordered by the Aleutian volcanic arc that passes into the deep waters of the northern Pacific Ocean.

Australia formed the northeastern part and coast of Gondwana. To the south lay Antarctica, to the southwest India – all parts of an ancient continental interior. An ocean edge still lay along the entire east coast, from Tasmania to east of Cape York. The warmth of the previous 191 million years had disappeared and the planet entered a phase of global cooling around 330 Ma ago – an icehouse. Central Gondwana became covered in an ice sheet and glaciers transported material outwards from the high mountain ranges, leaving moraines across the surrounding landscapes.