The problem of claiming to find the oldest fossils greater than 3 billions year sold sometimes turns out to likely not fossils after further research. The search has to for more specific fossils in large amounts and possibly strata. which will be difficult.
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The world’s oldest fossils or oily gunk? New research suggests these 3.5 billion-year-old rocks don’t contain signs of life
The world’s oldest fossils or oily gunk? New research suggests these 3.5 billion-year-old rocks don’t contain signs of life
Published: February 1, 2023 2:11pm EST
The Pilbara region of Western Australia is home to one of the most ancient surviving pieces of Earth’s crust, which has been geologically unchanged since its creation some 3.5 billion years ago.
Some of the oldest signs of life have been found here, in the North Pole area west of the town of Marble Bar, in black rocks composed of fine-grained quartz called chert.
Veins of black chert found in the Pilbara open a window onto Earth as it was 3.5 billion years ago. Birger Rasmussen
Some features in the so-called “Apex chert” have been identified as the fossilised remains of microbes much like the bacteria that still survive today. However, scientists have debated the true origin of these features ever since they were discovered 30 years ago.
In
new research published in Science Advances, we show the carbon-rich compounds also found in the chert may have been produced by non-biological processes. This suggests the supposed “fossils” are not remnants of early lifeforms but rather artefacts of chemical and geological processes.
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Controversial Pilbara fossils
In 1993, American palaeobiologist William Schopf spotted carbon-rich filaments in outcrops of the 3.45 billion year old Apex chert. He
interpreted them as the charred remains of fossilised microbes similar to cyanobacteria, which were Earth’s first oxygen-producing organisms and are still abundant today.
The existence of fossilised cyanobacteria in such old rocks would imply that life was already pumping oxygen into the air more than a billion years before Earth’s atmosphere became rich in oxygen.
A key piece of evidence in favour of life was the association of organic compounds with the ancient fossils. This is because living cells are made up of large organic molecules, which comprise mainly carbon as well as hydrogen, nitrogen, oxygen and other elements.
Tiny structures like these, found in ancient black chert, have been interpreted as fossilised bacteria.
Brasier et al.
In 2002,
Schopf’s interpretation was challenged by English palaeobiologist Martin Brasier and his team. They showed the “fossils” displayed a variety of shapes and sizes uncharacteristic of cyanobacteria, and indeed, inconsistent with microbial life. What’s more, they also showed the fossil-bearing black cherts were not horizontal beds deposited on the seafloor, but angled veins cutting across the underlying layers of rock.
The fossil-bearing cherts appeared to have formed at high temperatures during volcanic activity. Brasier argued this environment was hostile to life and the “fossils” were, in fact, formed from graphite impurities in the rock. They also speculated that the carbon associated with the “fossils” may not even be biological in origin.
A lively debate ensued, and it has continued ever since.
Microbes or hot fluids?
To try to determine where the carbon-rich deposits in the black chert veins came from, we took a very close look at them with a high-magnification electron microscope.
We found it did not come from fossilised bacteria. The oil-like substance occurs as residues in fractures and as petrified droplets, which have previously been mistaken for ancient fossils.
The textures in the black chert veins indicate they were formed when hot fluids rich in silica and carbon moved through cracks in lava flows below vents in the seafloor similar to modern “
black smoker” vents. Upon approaching the seafloor, the hot fluids infiltrated layers of volcanic sediment, replacing it with black chert.
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This may also be true of some claims of the possible fossils found in rocks from Mars.
Based on the conclusions of post #25 and other sources I believe that the search for the very simple first life forms is futile. The best ways that abiogenesis can be falsified to a degree is to recreate abiogenesis in the lab based on the environment and how replicating inorganic molecules can form the earliest simple life forms. I also believe that AI may have a significant role in this process.
