[meteorite-list] UCLA Scientists See and Analyze 650-Million-Year-Old Fossils Inside Rocks in 3D - a First, With Implications for Finding Life on Mars

[Ron Baalke]

University of California-Los Angeles

Contact: Stuart Wolpert
Phone: 310-206-0511

January 31, 2006

UCLA Scientists See and Analyze 650-Million-Year-Old Fossils Inside Rocks 
in Three Dimensions -- a First, With Implications for Finding Life on Mars

UCLA paleobiologist J. William Schopf and colleagues have produced 3-D 
images of ancient fossils -- 650 million to 850 million years old -- 
preserved in rocks, an achievement that has never been done before.

If a future space mission to Mars brings rocks back to Earth, Schopf said 
the techniques he has used, called confocal laser scanning microscopy and 
Raman spectroscopy, could enable scientists to look at microscopic fossils 
inside the rocks to search for signs of life, such as organic cell walls. 
These techniques would not destroy the rocks.

"It's astounding to see an organically preserved, microscopic fossil 
inside a rock and see these microscopic fossils in three dimensions," said 
Schopf, who is also a geologist, microbiologist and organic geochemist. 
"It's very difficult to get any insight about the biochemistry of 
organisms that lived nearly a billion years ago, and this (confocal 
microscopy and Raman spectroscopy) gives it to you. You see the cells in 
the confocal microscopy, and the Raman spectroscopy gives you the 
chemistry.

"We can look underneath the fossil, see it from the top, from the sides, 
and rotate it around; we couldn't do that with any other technique, but 
now we can, because of confocal laser scanning microscopy. In addition, 
even though the fossils are exceedingly tiny, the images are sharp and 
crisp. So, we can see how the fossils have degraded over millions of 
years, and learn what are real biological features and what has been 
changed over time."

His research is published in the January issue of the journal 
Astrobiology, in which he reports confocal microscopy results of the 
ancient fossils. (He published ancient Raman spectroscopy 3-D images of 
ancient fossils in 2005 in the journal Geobiology.)

Since his first year as a Harvard graduate student in the 1960s, Schopf 
had the goal of conducting chemical analysis of an individual microscopic 
fossil inside a rock, but had no technique to do so, until now.

"I have wanted to do this for 40 years, but there wasn't any way to do so 
before," said Schopf, the first scientist to use confocal microscopy to 
study fossils embedded in such ancient rocks. He is director of UCLA's 
Institute of Geophysics and Planetary Physics Center for the Study of 
Evolution and the Origin of Life.

Raman spectroscopy, a technique used primarily by chemists, allows you to 
see the molecular and chemical structure of ancient microorganisms in 
three dimensions, revealing what the fossils are made of without 
destroying the samples. Raman spectroscopy can help prove whether fossils 
are biological, Schopf said. This technique involves a laser from a 
microscope focused on a sample; most of the laser light is scattered, but 
a small part gets absorbed by the fossil.

Schopf is the first scientist to use this technique to analyze ancient 
microscopic fossils. He discovered that the composition of the fossils 
changed; nitrogen, oxygen and sulfur were removed, leaving carbon and 
hydrogen.

Confocal microscopy uses a focused laser beam to make the organic walls of 
the fossils fluoresce, allowing them to be viewed in three dimensions. The 
technique, first used by biologists to study the inner workings of living 
cells, is new to geology.

The ancient microorganisms are "pond scum," among the earliest life, much 
too small to be seen with the naked eye.

Schopf's UCLA co-authors include geology graduate students Abhishek 
Tripathi and Andrew Czaja, and senior scientist Anatoliy Kudryavtsev. The 
research is funded by NASA.

Schopf is editor of "Earth's Earliest Biosphere" and "The Proterozoic 
Biosphere: A Multidisciplinary Study," companion books that provide the 
most comprehensive knowledge of more than 4 billion years of the earth's 
history, from the formation of the solar system 4.6 billion years ago to 
events half-a-billion years ago.

IMAGE CAPTION:
[http://newsroom.ucla.edu/NewsReleaseImages/6796_images/6796a.jpg (728KB)]
A 650-million-year-old fossil from Kazakhstan. Top: optical image of 
fossil cyanobacterium. Middle: confocal optical image of the same fossil. 
Bottom L: close-up of section of confocal optical image. Bottom R: Raman 
chemical image of same boxed region.

Credit: Dr. J. William Schopf/UCLA