Timeframe: ~150 Ma–~34 Ma, Latest Jurassic to Eocene
Geological story
Gondwana breakup & inland seas, dinosaurs roam from South America to Queensland. Most of Australia under water in early Cretaceous, inland sea retreats as seafloor opens up progressively along western, southern and eastern margins. Last link with Antarctica severed as Tasmania slides away along its western edge around 34 Ma.
Rocks to show: marine deposits of the Cretaceous inland sea, Cretaceous volcanic arc in Queensland, Eocene marine deposits from southern margin, igneous rocks related to breakup.
Great Artesian Basin forms, the inland sea
Events
- ~140 Ma – sea starts to invade inland Australia from Gulf of Carpentaria
- ~126 Ma – see some of earliest flowering plants in Australia (Otway Basin)
- ~110 Ma – maximum extend of inland sea, extends into all inland states, aquiclude for GAB
- ~100 Ma – seas retreat from inland Australia
- 65 Ma – end Cretaceous mass extinction – dinosaurs, marine reptiles, pterosaurs & ammonites gone
- ~55 Ma – Paleocene–Eocene Thermal Maximum
- ~50 Ma – shallow seas in Nullarbor & Murray Basin as ocean widens between Australia & Antarctica
- ~34 Ma – Tasmania Antarctica breakup
Rocks included in this theme
- Gulaga (Mt Dromedary) igneous complex, NSW
- Bunbury Basalt, WA
