A patch of scrubland in Western Australia’s remote outback has been added to the National Heritage List. Its significance?
Erawondoo Hill, 800 kilometres north of Perth, is home to the oldest known mineral grains on Earth, zircon crystals, which date back an astonishing 4.4 billion years making them just 120 millions years younger than Earth itself.
“This is the most incredible treasure chest in the world,” said Martin van Kranendonk, director of the Australian Centre for Astrobiology at the University of NSW.
“It contains little fragments from our planet from just after it was born.”
Professor van Kranendonk described the area as “very dry, desolate, and very remote”.
It is also close to mining activity.
But the site continues to draw a stream of enthusiastic geologists to it from around the world.
“The hill looks like nothing particularly special, and if you looked at the rocks and broke them open, you’d say ‘There’s nothing particularly interesting there’, but of course the devil is in the detail,” he said.
“It’s moved people to such flights of fancy and thinking about our history, where we came from, what our planet went through to become a habitable environment where we could live.
“It’s actually inspired someone to write a symphony about it based on these 4.4-billion-year-old grains.”
Site one of most important in the world: Minister
Federal Environment Minister Sussan Ley said Erawondoo Hill was being recognised for its outstanding national heritage value.
She said it was one of the most important places in the world to research Earth’s origins.
“There is simply nowhere else where zircon crystals this old occur in such abundance,” Minister Ley said in a statement.
“This site has enormous scientific, educational and cultural value which deserves to be recognised and preserved.”
She said analysis of the crystals and surrounding sedimentary rocks have revolutionised scientific thinking on the earliest phases of Earth’s history.
The mineral deposit was discovered in the early 1980s and Professor van Kranendonk was thrilled the site was being protected.
“Nobody could believe it when they first found [out] the age and it’s still really hard to come to grips with something that old,” he said.
Professor van Kranendonk says the crystals hold the keys to our understanding of how Earth formed.
“These crystals not only have information about the time of their formation, they have information about the environment in which they form,” he said.
Professor van Kranendonk said the crystals formed from magma, or liquid rock, in the crust.
“As it cools, it has very specific compositional information,” he said.
“So it tells us about the nature of the crust that was forming at that time.
“So it tells us actually how our planet was cooling, how the first solid material came to be, and that can inform us a lot about where we might think to find life on other planets.”
Pilbara site also needs protection
Professor van Kranendonk is working with others to gain National Heritage recognition for another site in West Australia’s Pilbara.
The North Pole Dome, near Port Hedland, is vulnerable to destruction by fossil collectors and possible mining activity, he says.
Professor van Kranendonk said the site had the oldest evidence of any type of life on Earth and was visited by NASA and European Space Agency scientists last year to help them learn how to explore for signs of life for an upcoming rover mission to Mars.
“We are working also very hard to get that listed as a National Heritage listing,” he said.