Amazing stuff! This is not the latest research, but fascinating nevertheless.
"A chance encounter in remote Australia, and years of painstaking analysis has pushed back evidence for the start of complex life on the planet by 750 million years. ...
Independent dating of the rock layers surrounding the embedded black chert suggest the microfossils are about 2.4 billion years old. ..."
From the abstract:
"The great oxidation event (GOE), ~2.4 billion years ago, caused fundamental changes to the chemistry of Earth's surface environments. However, the effect of these changes on the biosphere is unknown, due to a worldwide lack of well-preserved fossils from this time. Here, we investigate exceptionally preserved, large spherical aggregate (SA) microfossils permineralised in chert from the c. 2.4 Ga Turee Creek Group in Western Australia. Field and petrographic observations, Raman spectroscopic mapping, and in situ carbon isotopic analyses uncover insights into the morphology, habitat, reproduction and metabolism of this unusual form, whose distinctive, SA morphology has no known counterpart in the fossil record. Comparative analysis with microfossils from before the GOE reveals the large SA microfossils represent a step-up in cellular organisation. Morphological comparison to extant micro-organisms indicates the SAs have more in common with coenobial algae than coccoidal bacteria, emphasising the complexity of this microfossil form. The remarkable preservation here provides a unique window into the biosphere, revealing an increase in the complexity of life coinciding with the GOE."
Erica picked up a rock by chance 10 years ago. It might hold the oldest form of complex life on Earth A fossil found inside a souvenir 'pet rock' could push the start of complex life on Earth back by about 750 million years.
Fig. 1 Archetypal large spherical aggregate (SA) microfossils with wide, kerogen-free surrounding rinds. Microfossil shape is most commonly spherical, with radial symmetry.
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