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A billion years on Earth in 40 seconds

Clare Peddie, February 11, 2021 7:00PM The Advertiser

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A still image from the time-lapse video that for the first time shows the uninterrupted movement of the Earth’s tectonic plates over the past billion years. Picture: University of Adelaide/Professor Alan Collins media_cameraA still image from the time-lapse video that for the first time shows the uninterrupted movement of the Earth’s tectonic plates over the past billion years. Picture: University of Adelaide/Professor Alan Collins

geography

Reading level: orange

University of Adelaide scientists have released a video that, for the first time, shows the movement of the Earth’s tectonic plates over the past billion years.

Tectonic plates are the moving pieces of the Earth’s crust.

Viewers get to race through the time-lapse series – which highlights Adelaide in red – in just 40 seconds.

The video is part of a serious international research project published in Earth-Science Reviews. But it is also fascinating for non-experts, helping show in an instant how dynamic* and interesting our planet really is.

The co-author and leader of Adelaide’s Tectonics and Earth Systems Research Group, Professor Alan Collins, said “the plates really dance around dramatically”.

He said rocks where Adelaide now stands were old enough to feature in the entire video.

“You can’t really put Melbourne and Sydney in because they’re sitting on rocks that are too young,” he said.

But the rocks that make up “the basement of Adelaide” were ancient.

“If you drilled down from the city centre, down hundreds of metres, you’d come to some quite solid crystalline shiny rocks,” Prof Collins, of the University of Adelaide, said.

“They’re part of a thing called the Gawler Craton, which is really the old part of Australia and joins on with Yilgarn Craton in Western Australia, and it’s really part of the multiple billion-year-old kernel* of the continent.”

Adelaide is right on the edge of that old bit of continent, whereas everything from the Mount Lofty Ranges east is much younger. (Still old, but less than half a billion years old).

Tectonics: Watch Adelaide rocking around the world

The next big challenge is to use the modelling to work out how deep seas were and how high the mountains were through this time.

Then scientists can model the shape of the Earth’s surface over a billion years and start to put it into global climate models.

Prof Collins can envisage* a three-dimensional model of plate tectonics, showing mountains rising and falling.

He describes continents as “the scum of the Earth”, literally, like the slag that rises to the surface in an iron furnace.

There have been models showing movement of the continents in the past, but this is the first showing the plates.

Lead author and creator of the video Dr Andrew Merdith began work on the project while a PhD student in the School of Geosciences at the University of Sydney.

Earth scientists from every continent have collected and published data, often from inaccessible and remote regions, that Dr Merdith and his collaborators have put together over the past four years to produce this billion-year model.

It will allow scientists to better understand how the interior of the Earth convects*, chemically mixes and loses heat via sea floor spreading and volcanism. The model will help scientists understand how climate has changed, how ocean currents altered and how nutrients fluxed* from the deep Earth to stimulate biological evolution.

media_cameraUniversity of Adelaide Professor Alan Collins from the Tectonics & Earth Systems Research Group in the Department of Earth Sciences. Picture: supplied

Prof Collins is thrilled with the result and the reaction to date. The original video — without the spotlight on Adelaide — has been viewed more than half a million times on YouTube, Twitter and other websites, including The New York Times.

“This is the sort of thing I’ve been working towards for 20 years,” he said.

“I’ll see out pretty much the rest of my career doing more of this, improving and working on the implications of this.”

Thingvellir National Park Iceland media_cameraThe Þingvellir or Thingvellir National Park in Southern Iceland. The rift valley is on tectonic plate boundaries.

WHAT HAPPENS NEXT?
“Australia is moving rapidly north and is going to be part of Asia whether we like it or not, but not in the next 100 years or so, we’re talking about the next 10 million years or so. We are rapidly moved into moving north and will sideswipe China,” Prof Collins said.

“In the future, the big unknown actually though is what’s going to happen with the Pacific, whether the Americas are going to move across the Pacific and then collide with Asia or whether the Atlantic will just close and the Americas will go back to Europe.”

GLOSSARY

  • dynamic: moving and changing
  • kernel: seed, beginning of something
  • envisage: be able to imagine
  • convects: transports or moves something by hot things rising and cool sinking
  • fluxed: flowed

EXTRA READING

What is at the centre of the Earth?

Scientists map ancient lost continent

Climbers to remeasure height of Everest

Is Africa starting to split in two?

QUICK QUIZ

  1. What are plates on the Earth’s surface called?
  2. What time period does this time-lapse video show?
  3. Where are the researchers from?
  4. In which direction is Australia moving?

LISTEN TO THIS STORY

CLASSROOM ACTIVITIES
1. Write the Script
Watch the video. Write the script for a voiceover or commentary that will help kids watching the video to understand what the video is about.

Time: allow at least 30 minutes to complete this activity
Curriculum Links: English, Science, Media Arts

2. Extension
What information or data do you think the scientists needed to help them to produce the billion-year model? List as many things that you can think of.

Time: allow 20 minutes to complete this activity
Curriculum Links: English, Science

VCOP ACTIVITY
Opener Up-Level It
Make a list of all the openers in the article. Pick three that repeat and see if you can replace them with another word, or shuffle the order of the sentence to bring a new opener to the front.

Don’t forget to re-read the sentence to make sure it still makes sense, and that it actually sounds better.

HAVE YOUR SAY: What would you like to make a time-lapse video of?
No one-word answers. Use full sentences to explain your thinking. No comments will be published until approved by editors.

Extra Reading in geography