The inland sea existed in a stable form between 27,000 and 17,000 years ago. (Representative pic)
An area of land north of modern Australia that was submerged thousands of years ago by rising seas once hosted as many as 500,000 people, a new study has revealed. In the newly published study in Quaternary Science Reviews, researchers at Griffith University in Brisbane, Australia, reconstructed the topography of around 400,000 square kilometres of land that is now covered by the Indian Ocean. They found that the land that was once believed to be uninhabitable was home to thriving populations of people for tens of thousands of years.
According to the study, the now-drowned continental shelves of Australia were thought to be environmentally unproductive and little used by First Nations peoples. However, now authors of the study said that mounting archaeological evidence shows this assumption is incorrect. They believe that many large islands of Australia's coast - islands that once formed part of the continental shelves - were occupied by around 500,000 people before sea levels rose.
Lead author of the study Kasih Norman noted that Geoscience Australia has recently released detailed sonar data, with each pixel representing an area of just 30 by 30 metres. "This is a high enough resolution to be able to talk about landscape features that were important to people," she said.
As per the study, the inland sea existed in a stable form between 27,000 and 17,000 years ago. A 2000-square-kilometre freshwater lake nearby was also stable from 30,000 to 14,000 years ago. The lake would have been a vital refuge for people escaping the arid conditions of the Australian continent to the south, the study authors said.
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The team estimated that the region could have supported a population of between 50,000 and 500,000 people. "This massive landscape that is not there now would have been unlike anything that we have in Australia today," said Ms Norman. "To have a freshwater lake of that size next to an inland sea is just incredible and people would have been living across it. This is a lost landscape that people were using," she added.
According to the study, at first, the sea rose by around a metre every 100 years. However, from 14,500 to 14,100 years ago, it rose 4 to 5 metres every 100 years. At that rate, people would have been able to watch the sea levels rise and would have been forced to move inland to escape inundation, Ms Norman said.