The sea that could engulf Australia

THE bone-dry red heart of our country was once a vast ocean, filled with prehistoric marine life. That water could return.

ONE hundred million years ago, the bone-dry red heart of Australia was almost entirely covered, by a vast sea populated with strange prehistoric marine life.

Experts warn that the water could one day flow back to engulf the fragile world humans have created, submerging rock and sand beneath a wide, shallow ocean and forcing us out.

The return of the Australian sea could be triggered by climate change, a meteor shower, an Ice Age or other natural phenomena, which could strike tomorrow or in millions of years.

We would not recognise the waterlogged version of this country from the Cretaceous period.

“Australia looked like an archipelago with land down the east and west,” Adelaide science writer Danielle Clode told news.com.au. “The sea was dominated by marine reptiles, plesiosaurs, ichthyosaurs, Loch Ness monster-type creatures, things that look like dolphins, only much bigger.”

The northern coast was warm, while the water was near freezing on the southern coasts, crusted by ice. Shark and turtles swam in ammonite-filled waters, alongside amphibians similar to the modern-day Chinese giant salamander.

Winged pterosaurs soared overhead and the Koolasuchus, an ancestor of the crocodile,crawled through the cooler southern climes. Lagoons were edged by forests filled with the unfamiliar conifers, ferns, pines and ancient ginkgo trees that used to be Australia’s native flora.

The country could again be a home to creatures like plesiosaurs.

More fossils from this time are regularly discovered, and they could provide clues as to what we can expect if the country slips back under the sea again, and what we may be able to do to stop that happening.

“Australia is an old country and it’s been the same for a long time, but it has changed dramatically,” said Clode, author of Prehistoric Marine: Life in Australia’s Inland Sea. “We need to think about what climate is suited to us. These animals were sensitive to climactic conditions — and so are we.”

There’s a part for all of us to play. Palaeontologists rely on amateurs living in Australia’s huge inland desert area to help them, and it’s locals who have been responsible for some of the biggest discoveries.

Before dolphins, reptilian ichthyosaurs lived in the the sea that covered Australia. Picture: Todd Marshall

The secrets of this maritime kingdom remain hidden, not only in the red rock of the country’s centre, but in deposits around the coast of Western Australia and the Northern Territory, and rivers in Victoria. The Eromanga Basin is home to major fossil sites in several opal-mining districts of South Australia and NSW, while western Queensland is known for its dinosaur and marine fossils.

It was an asteroid that spelled the end for Australia’s great sea, and the entire Cretaceous period, filling the sky with debris and blocking out the sun. In this summerless world, three quarters of the Earth’s species died out, with ocean life particularly hard hit by the lack of light and food.

Eventually, the earth was repopulated, and surviving turtles, sharks, fish and birds were joined by mammals, and us.

We can only wonder what lies ahead fro Australia. Will the sea return? And will there be anyone here to see it?