Australia in the Cretaceous

Article | Updated 8 years ago

Globe

Australia in the Cretaceous was very different from today with volcanoes, shallow inland seas and great rift valleys.

The southern supercontinent Gondwana included Australia, South America, Africa, India, Antarctica and others. It had started to break up in the Jurassic some 160 million years ago but in the Early Cretaceous this intensified.

Globe

The break up of Eastern Gondwana
The globe below shows Australia in the Early Cretaceous, breaking away from Antarctica having separated from India. Much of the continent is covered by shallow seas.

Early Cretaceous

A rapidly expanding seaway opened up between the western edge of Australia and India 130 million years ago. Also a deep opening, called a rift valley, was slowly forming between what is now the southern coast of Australia and Antarctica as these continents began to break apart. In the later part of the Early Cretaceous, up to 50 percent of the Australian continent was repeatedly flooded with shallow seas caused by rising global sea levels and vertical movements of its crust.

Late Cretaceous

Around 95 million years ago, volcanic activity along the north-eastern edge lifted the continent in the east and the huge inland sea dried up. The sea was replaced by vast floodplains that provided an ideal habitat for sauropods and other dinosaurs. Many fossilised dinosaur remains are currently being uncovered in central Queensland particularly from the Winton Formation. The western edge of Australia remained underwater throughout much of the Late Cretaceous and marine rocks of this age are exposed in the Perth and Carnarvon Basins.