on an outcrop From exposed volcanic and sedimentary rock on the eastern shores of Hudson Bay in northern Quebec, researchers have discovered what may be the first fossilized life forms ever discovered. These microbial ancestors lived between 3.75 and 4.28 billion years ago, just 300 million years after the Earth formed, a blink of an eye on geological time scales. If life developed so rapidly on Earth, it suggests that abiogenesis, the process by which nonliving matter turns into a living organism, is potentially “easy” to accomplish, and life in the universe may be more common. than we thought.
Evidence for these early life forms comes from the Nuvvuagittuq supracrustal belt, a rocky outcrop that once lay deep in the ocean near a hydrothermal vent system. Since then, the Belt has risen to the surface, after many millennia of geological changes and tectonic activity. In 2017, researchers discovered tiny filaments in the Belt that appeared to have been produced by bacteria, but the evidence was inconclusive. They couldn’t rule out chemical processes that could create similar patterns in the rock.
Since then, the team has been examining samples from the Belt more carefully, and this month published a new article on Progress of science strengthening the case for life. Not only did they find more examples of filaments, spheres, and tubes like those initially described in 2017, but they also found a larger, more complex structure, shaped like a “tree” with parallel branches, that is unlikely to have a chemical explanation.
The new research not only suggests a biological origin for the fossils, but also suggests early diversity, with life forms drawing energy from different sources. Mineralized chemical byproducts in the rock suggest that microbes in the Belt lived on iron, sulfur, and perhaps carbon dioxide and light, a form of photosynthesis.
Lead author Dominic Papineau explains that “using many different lines of evidence, our study strongly suggests that several different types of bacteria existed on Earth between 3.75 and 4.28 billion years ago.”
To rule out geological and chemical explanations for the fossils, the team subjected the samples to various tests. By looking at paper-thin slices of rock under the microscope, they determined that the filaments are best preserved in fine quartz, which is less susceptible to metamorphic change than rough quartz. This suggests that the filaments were not created through metamorphism (the heating and compression of rock). Similarly, they looked at the levels of rare earth elements in the Belt and compared them to rock formations of similar age in other parts of the world, to more accurately date the site and confirm that the fossils were indeed as old as they appear.
After completing this careful program of analysis, the team believes that living organisms are the most likely explanation for the filaments in the Belt, but there is always room for uncertainty. The possibility remains that the “fossils” were formed through non-living processes.
The researchers are confident that even if they are abiotic, they “could still indicate complex prebiotic forms on early Earth.”
The discovery has potentially substantial implications for the search for life elsewhere in the Solar System. It means that under the right conditions, life can form very quickly and could be anywhere. But you don’t have to take my word for it.
The paper itself concludes that if “it only takes a few hundred million years for life to evolve to an organized level on a primordial habitable planet…such microbial ecosystems could exist on other planetary surfaces where liquid water interacted.” with volcanic rocks, and… extraterrestrial life may be more widespread than previously thought.”
This article was originally published on universe today by Scott Alan Johnson. Read the original article here.