The formation of K’gari about 1 million years ago might have been instrumental in the formation of the Great Barrier Reef, research suggests.
Once known as Fraser Island, K’gari is the world’s largest sand island at 1840 square kilometres, made up of sand that has accumulated on the volcanic bedrock of the east Australian continental shelf.
Research has lent further weight to the theory that the accumulation helped spur the growth of the Great Barrier Reef.
Paleoecologist Professor Patrick Moss, a supervising researcher and Head of School at the University of Queensland’s School of Earth and Environmental Sciences said the work confirmed a more exact age for K’gari.
UQ PhD candidate Daniel Ellerton conducted the experiments, getting sand samples from deep within K’gari and the nearby Cooloola sand formation on the mainland.
“When sand is buried it traps electrons within the lattice of the sand grains, and then you stimulate the grains and measure the wavelength of the light they put out, which gives you the time they’ve been buried for,” he said.
“It’s like a clock … but you have to keep them completely out of sunlight until you test them, otherwise it resets the clock.”
The research confirmed K’gari and the Cooloola formation were laid down between 1.2 million and 700,000 years ago.
It is known that sea levels fluctuated significantly at that time because of the arrival and then retreat of an ice age, which Moss said would have been able to condense the huge amounts of sediment into discrete formations.