An international team of scientists has found the remains of a huge undersea landslide hiding on the Great Barrier Reef. According to the team, the landslide measures about 30 times the volume of Uluru, the famous sandstone in the Australian Northern Territory’s arid “Red Centre.”
Researcher Robin Beaman, from the university, adds that the slip, which has been named Gloria Knolls slide, was found just 75 kilometers off the coast of north Queensland, near the Innisfail town. The research team was actually working on the blue-water research ship of the Marine National Facility, called the Southern Surveyor.
According to Beaman, this landslide is all that remains after the great collapse of sediment that occurred over 300,000 years ago. Overall, the scientists estimate that the sediment’s size is 32 cubic kilometers.
A field of debris composed of knolls or blocks and a bunch of other smaller blocks can be found all over the area located 30 kilometers from the main landslide. This continues into the Queensland Trough, about 1,350 meters down. “We were amazed to discover this cluster of knolls while 3D multibeam mapping the deep GBR seafloor. In an area of the Queensland Trough that was supposed to be relatively flat were eight knolls, appearing like hills with some over 100 m high and 3 km long,” he says in a press release.
The JCU discovery was also made possible by collaboration with the University of Sydney. University of Sydney’s associate professor, Jody Webster, compares the mission to a story typical of detectives. Like a detective, they had to find the knolls first, and then they utilized a map to determine the source of the landslide knolls.
The researchers found that a sample of the sediment from a knoll, located 1,170 below, reveals a community of coral that reside in cold water. They also found a living, as well as fossilized species of corals like the gorgonian sea whips, bamboo corals, mollusks and stalked barnacles. “The oldest fossil corals recovered off the top of the knoll were 302 thousand years,” adds the study’s lead author, Angel Puga-Bernabéu of the University of Granada, “which means the landslide event that caused these knolls must be older”.
Landslides like this could pose a tsunami risk to coastlines. However, the researchers say that more investigations are still needed to completely determine the tsunami hazard to Queensland’s coast. Other researchers also included those from the University of Edinburgh and the Australian Nuclear Science and Technology Organization.