How algae conquered the world – and other epic stories hidden in the rocks of the Flinders Ranges
Evidence of how it came to be so beautiful and nurturing is locked in the rocks of South Australia’s Flinders Ranges – a site now vying for World Heritage listing.
- Evidence of how it came to be so beautiful and nurturing is locked in the rocks of South Australia’s Flinders Ranges – a site now vying for World Heritage listing.
- Their legacy is the oxygen we breathe and the evolution of the first animals more than 500 million years ago.
- The soft bodies of these animals have been exceptionally preserved at the new Nilpena-Ediacara National Park, which opened in April 2023.
A superbasin on the shores of the Pacific
- The rocks of the Flinders Ranges formed at the same time as the Pacific Ocean basin.
- The plate tectonic “dance of the continents” tore North America away from Australia 800 million years ago.
- Geologists call this the Adelaide Superbasin.
Land of fire and ice
- The planet plunged into an 80-million-year Ice Age, the likes of which has never been seen again.
- The Cryogenian contains a least two global glaciations when the planet became covered in ice - an occurrence earth scientists refer to as “Snowball Earth”.
- Read more:
Ancient volcanic eruptions disrupted Earth's thermostat, creating a 'Snowball' planet
Part One: Picturing the world before the first animals
- The glaciers ploughed through hills and valleys, planing off the country and leaving behind vast swathes of boulder clay that now forms rocks over much of the Flinders Ranges.
- We used these variations to build a picture of highly saline shallow seas rich in bacterial life, but devoid of much else.
Part Two: Dating Snowball Earth
- Using established methods we can date one of the minerals in the sand (zircon).
- This enabled us to more accurately date the Snowball Earth rocks in the Flinders Ranges called the Sturt Formation.
- It is the first study to directly date sedimentary rocks that formed during the Snowball Earth event.
- So the planet experienced more of a cold period rather than a completely frigid snowball.
The rise of the algae
- The geological processes and their timing helps us understand how the Earth system came to be.
- The frozen world of the Cryogenian stressed the microbial life that dominated the oceans way back then.
- This newcomer was algae, life with cells containing a nucleus.
A place of true world heritage
- Our research into these rocks links the interdependence of Earth systems.
- The stories locked in the hills of the Flinders Ranges undoubtedly give the region a heritage value to the world.
- We eagerly await news of world heritage listing, which is not expected until 2025 at the earliest.