Scientists say sea-level changes formed Australia’s K’Gari Sand Island, Great Barrier Reef

How did the world’s largest sand island Okay’gari, the indigenous identify for japanese Australia’s Fraser Island, together with the Great Barrier Reef, the world’s largest coral reef, come to be? Little is thought in regards to the formation of those UNESCO World Heritage-listed websites, which have been influenced by a steady, long-term tectonic historical past over the Quaternary interval that started 2.6 million years in the past.

However new findings by Utah State College geoscientist Tammy Rittenour and a global group of colleagues level to a modern-day concern that would have initiated the enduring landforms’ beginnings some 800,000 years in the past: sea-level rise.

Rittenour and researchers from the College of Queensland, Australian Nationwide College, Flinders College, the College of Western Australia, the College of Canterbury, Clarkson College and Stockholm College report the findings within the Nov. 14, 2022 situation of Nature Geoscience. The group’s analysis was supported by an Australian Analysis Council grant.

“Our research provides evidence that the formation of K’gari and the Great Barrier Reef are linked to a change in the magnitude of sea-level rise and fall due to major climate feedback changes during the Middle Pleistocene Transition,” says Rittenour, professor in USU’s Division of Geosciences and the Ecology Middle.

Utilizing sediment samples from hand cores and seashore bluffs, Rittenour, director of the USU Luminescence Laboratory, used optically stimulated luminescence relationship to constrain the time of formation of the island’s intensive, brightly hued sand dunes, in addition to these from the adjoining Cooloola Sand Mass.

“We found that the sand island and dune fields first formed 1.2-0,7 million years ago, during a period of climate reconfiguration, when increasing global ice volume caused sea-level fluctuations that redistributed sediment previously stored on the continental shelf,” Rittenour says. “The formation of K’gari prevented the transport of sand northward along the coast, into the areas that now host the Great Barrier Reef.”

The outward-jutting orientation of the large sand island created circumstances for the crystal-clear water wanted for coral progress, permitting the event of the Great Barrier Reef.

“These significant findings are changing the way we look at coastal sedimentary systems,” Rittenour says. “This wholesale change in coastal conditions during the middle Pleistocene is probably not unique to eastern Australia’s coast and should be investigated in other passive-margin coastlines around the world.”