A new study by researchers at University College London (UCL) suggests that a variety of microbial life existed on Earth at least 3.75 billion years ago.
Researchers analyzed a fist-sized rock from Quebec, Canada, estimated to be between 3.75 and 4.28 billion years old. While earlier analysis of the rock revealed tiny filaments, knobs and tubes created by bacteria, in the new analysis the team discovered a stem with parallel branches on one side that measures almost a centimeter long – as well as hundreds of distorted spheres or ellipsoids.
While some of the structures could have been created by chance chemical reactions, the “tree-like” stem with parallel branches was most likely of biological origin, as no structure created solely by chemistry was found as the latter, said the researchers, who also provided evidence of how bacteria obtain their energy in different ways.
“This means that life could have started as soon as 300 million years after Earth was formed. In geological terms, that’s fast – about one lap of the Sun around the galaxy,” the lead author said. , Dr. Dominic Papineau (UCL Earth Sciences, UCL London Center for Nanotechnology, Center for Planetary Sciences and the China University of Geosciences), who collected the rock samples in 2008.
The team compared the structures and compositions to more recent fossils and also analyzed the rock specimens under various light and Raman microscopes, concluding that the hematite structures could not have been created by compression and heating. rock (metamorphism) over billions of years.
The study also pointed out that structures appeared to be better preserved in finer quartz (less affected by metamorphism) than in coarser quartz (which underwent more metamorphism).
The research is published in the journal Science Advances and involved researchers from UCL Earth Sciences, UCL Chemical Engineering UCL London Center for Nanotechnology and the Center for Planetary Sciences at UCL and Birkbeck College London, as well as from the US Geological Survey, Memorial University of Newfoundland in Canada, the Carnegie Institution for Science, the University of Leeds and the China University of Geoscience in Wuhan.
More details can be found here.