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

From: David Campbell <>
Date: Thu Jun 07 2007 - 12:05:00 EDT

> 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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Received on Thu Jun 7 12:05:18 2007

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