Biological processes, not non-living ones, are the source of 3.48 billion-year-old rock formations in Western Australia, according to a new study by an international team of scientists. The findings could help researchers in their quest in finding signs of life on Mars, which has similar rock formations.
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The rocks in question are stromatolites and are found in Dresser Formation in Pilbara, Western Australia. According to a press release, these layers of rocks are formed by the excretions of photosynthetic microbes that lived billions of years ago in shallow, nutrient-rich lagoons.
Paleontologists at the Natural History Museum in London have confirmed that these formations are in fact the fossilized remains of living organisms that existed more than 3.48 billion years ago, contrary to some scientists’ claims that they are merely geological in nature.
In a new study, published in the journal Geology, researchers examined samples from stromatolites in greater detail than ever before. To establish the biological origins of the rocks, researchers analyzed the formations using high-resolution 2D and 3D imaging techniques.
“Although our samples no longer contain microfossils or organic materials, they nonetheless have many characteristic structures that [indicate] a biological origin,” Keyron Hickman Lewis, lead author of the study, said in a statement to the Natural History Museum.
“Imaging these structures with high-resolution techniques allows us to build a compelling case for how they might have formed due to the action of life,” she added.
The characteristics of Australian stromatolites (notably iron-rich soil and heavy, ancient weathering) make them similar to the surface of Mars. So, the techniques used in this new study could help investigate the possibility of life on Mars.
“The deep iron-rich weathering profile of the Dresser stromatolites makes them pertinent analogs for potential microbialites on Mars,” Hickman Lewis said.
The latest discovery can also help in the analysis of samples at the edges of Mars’s Jezero crater. Space scientists believe that billions of years ago, this crater hosted a lake.
Martian samples are expected to arrive on Earth in the 2030s. Currently, NASA’s Perseverance rover is exploring the surface of the Red Planet near the Jezero crater.