Dr. Hap McSween from the University of Tennessee and fellow researchers have found new evidence for water on Mars by re-examining the Shergotty Stone, a meteorite found in India in 1865. Until five years ago, Mars was viewed as a dry and dusty planet, unable to support life as we know it.
Recent images from the Mars Global Surveyor have prompted some scientists to propose a much more watery past for the red planet, one that might even have supported life. The images from space show evidence of oceans and lakes -- evidence that has, until now, been contradicted by findings from the Martian meteorites found on earth.
But in an article in today's issue of Nature, McSween (geological sciences) and colleagues from UT, Oak Ridge National Laboratory, the Massachusetts Institute of Technology and the University of South Florida show, for the first time, that a Martian meteorite once contained water.
"People have accepted, mostly from the rock evidence, that Mars is dry," said McSween. "Now we are seeing evidence that Mars is actually wet, that there may even be water seeping out now. Our team wanted to find some place for the two sets of evidence to converge."
McSween and fellow researchers found evidence for water in the Shergotty Stone through two independent lines of inquiry, one that involved studying the patterns of water-soluble trace elements, the other reproducing the order in which the meteorite's crystals were formed.
Both showed evidence that the meteorite was formed in a watery magma layer before being propelled to the surface by one of the volcanic eruptions that probably formed the Martian ocean.
McSween has studied the Shergotty meteorite for 23 years now.
"It's kind of amazing that after more than two decades we are still finding out new things from this one rock," he said. "It's an indication of the increasing sophistication of the techniques available to us."
Related website:
Mars Global Surveyor
[Contact: Dr. Hap McSween, Zoe Hoyle]
25-Jan-2001
