Enormous Pleistocene Landslide Discovered Off The Coast Of Australia

The findings, published in the journal Marine Geology, shed new light on the deepest reaches of the Great Barrier Reef, the world's largest coral reef ecosystem.

The ancient landslide, likely caused by a strong quake that could have generated a tsunami wave 27 metres (90 feet) high, was discovered unexpectedly by researchers conducting three-dimensional mapping of the seafloor around the world's biggest reef.

But, the wave would likely be reduced by the presence of coral reefs.

The study was published on February 6 in the journal Environmental Science & Technology.

That series of knolls, now called the Gloria Knolls Slide complex, were the result of the ancient landslide, the researchers found.

Researchers then sampled the cold-water corals on one of the eight hills to find the age of landslide.

"The oldest fossil corals recovered off the top of the knoll was 302,000 years", said Dr Angel Puga-Bernabéu of the University of Granada, who was the lead author on the study. "We believe an natural disaster of sufficiently large magnitude was the most likely trigger for such a landslide event", study researcher Robin Beaman of James Cook University in Queensland, Australia, told Live Science in an email.

A process was started to create a 3D deep sea map of the areas around the Great Barrier Reef.

"We now know that they belong to this very old underwater landslide, a huge feature actually".

"When we brought a sample up there was a lot more marine life there than we ever anticipated, so that was a real surprise".

Header image: North-westerly view of the Gloria Knolls Slide and Gloria Knolls off Innisfail.

A better understanding of the geological structure of the seafloor will also help improve oceanographic knowledge of the area, Beaman said.

"This is another example of why coal and the Great Barrier Reef don't mix", said Sam Regester, campaigns director for the activist group GetUp! James Cook University's researcher Dr Robin Beaman said in a statement. An exciting coral community of both living and fossil cold-water coral species, gorgonian sea whips, bamboo corals, molluscs and stalked barnacles were also uncovered from sand sediment within a knoll.

"Beyond [100 feet] there is still very little studied".

Associate Professor Guillermo Diaz-Pulido from Griffith's School of Environment says it is because algae will compete for space with corals in the reef, much like a weed, and eventually take over.

  • Tracy Ferguson