The Pilbara is known for its fantastic array of stromatolite fossils. Once thought to have been a shallow, ancient aquatic landscape, a discovery of ancient hot springs has opened up a whole new field of research on the origins of land life.
The discovery of fossil stromatolites, structures formed by layers of cyanobacteria, in the Pilbara, supports the theory that early life may have evolved in hot springs rather than deep-sea hydrothermal vents. The discovery of possible life inside the hot springs could even shed light on our search for life on Mars.
“To actually find hot spring deposits is like a smoking gun for the story of a terrestrial hot spring setting for early life on the planet." Says Tara Djokic from the Australian Centre for Astrobiology at the University of New South Wales.
Image: Stromatolite in Shark Bay
The findings suggest that the Dresser Formation is the oldest land-based hot spring in the world. The discovery also re-dates the first exposed land by 130 million years and fossil life by 580 million years.
Professor Martin Van Kranendonk says the evidence of hot springs is clear due to the distinct mineral deposits or geyserite created from the hot spring water splashing against land. He explains:
We have this incredibly delicate texture preserved, with all these shapes and fabrics, and some of those include overlaps of layers that are characteristic of what we see in modern hot springs where there's a pool and a rim that accretes out over the pool.
Image: Stromatolite found in Glacier, Source: Wikimedia Commons
The case for Stromatolites is even more promising. Fossilised gas bubbles were found which are only produced in bubbly, microbial material. Stromatolites are layered columns of sedimentary rock that form layers of cyanobacteria, a single-celled photosynthesizing microbe.
Image: Modern Anemone Geyser, Source: Flikr
So what does this mean for the search for life on Mars?
Mars’ next Rover mission in 2020 may land right next to a Hot Spring the same age as the Dresser spring on earth. Tara Djokovic explains using the Dresser Hot Spring as an analogue will be “a huge driver for how we research for life elsewhere.”