Research Offers Insight Into How Oldest Fossils Formed

Microfossils provide important clues about the early history of life on Earth; however, some mystery still surrounds how they were preserved. (Image: via   pixabay  /  CC0 1.0)
Microfossils provide important clues about the early history of life on Earth; however, some mystery still surrounds how they were preserved. (Image: via pixabay / CC0 1.0)

Researchers at The University of Western Australia have uncovered evidence of a new type of fossilization that may explain how some of Earth’s oldest microfossils formed and might even help scientists detect evidence of past life on other planets.

Microfossils provide important clues about the early history of life on Earth; however, some mystery still surrounds how they were preserved. It is generally thought that many of the oldest microfossils formed when silica grew on their cell walls, encasing the microorganism.

When the microorganisms died, their cells rapidly decayed, leaving behind only traces of carbon in a hollow cavity that molded the shape of the organism.

The scientists worked on the 340-million-year-old Red Dog zinc-lead deposit in northern Alaska and found the carbon filling of semi-hollow microfossils was not derived from the original organism, but from migrated oil.

UWA Professor Birger Rasmussen from the School of Earth Sciences said the team found that oil infiltration of silica-entombed bacteria was responsible for producing the structures, which resembled many of the oldest microfossils preserved in the rock record. Rasmussen said:

Professor Rasmussen said the formation of carbon-rich microfossils around fractures suggested oil moving through the cracks in the rock had seeped into the semi-hollow molds left after the bacteria died, adding:

Provided by: Jess Reid, University of Western Australia [Note: Materials may be edited for content and length.]

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