Re: [asa] Direct dating of Archean microbial ichnofossils to 3.35 Ga

> Radiometric dating has confirmed that microscopic tubular structures in
> ancient lavas date back billions of years. These structures are thought to
> show that life thrived in volcanic rocks deep within the early Earth.

Nature's summary is a bit misleading. Volcanic, basalt, pillow
basalt, lava, and glass are surface features, not deep within the
earth. They're often fairly deep within the ocean-pillows are
characteristic of undersea volcanism. These were microbes boring into
rock exposed on the seafloor, not microbes in rock within the crust.

-- 
Dr. David Campbell
425 Scientific Collections
University of Alabama
"I think of my happy condition, surrounded by acres of clams"
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