Life of Mars?

University of Hawai'i University Relations Media & Publications Honolulu, HI 96822

(808) 956-8856 Telephone (808) 956-3441 Facsimile ur@hawaii.edu E-Mail

For Immediate Release:

Contact: Cheryl Ernst (808) 956-5941

May 22, 1997

New Findings by UH Scientists Challenge Report of Fossil Life from Mars

UH researchers have discovered important evidence that counters the claims that a Martian meteorite contains signs of ancient life on Mars. The scientists' findings, announced last week, suggest that carbonates in the meteorite resulted from melted material created by a giant impact on Mars rather than from living organisms.

Possible fossil Martian organisms were reported last August in carbonates in the meteorite ALH84001. UH scientists Ed Scott, Akira Yamaguchi and Sasha Krot say these carbonates and minerals in them were formed at high temperatures from melted material and could not have been formed by organisms.

The scientists' paper, which appears in the May 22 issue of the journal Nature, provides evidence that the carbonates and two other minerals in the meteorite ALH84001 formed from melts during a large impact 4 billion years ago. The scientists used electron microscopes to analyze tiny grains of carbonate and silicates in fractures in the rock and compared what they found in the Martian meteorite with other meteorites that had experienced giant impacts.

Scott and his colleagues infer that the impact melted tiny carbonates and squirted the melts into fractures in the rock. Within seconds the melts cooled and the cracks were squeezed tight, leaving tiny carbonates embedded inside the fractured rock. Two silicate minerals, feldspar and silica, melted simultaneously and squirted into cracks to form glasses next to the carbonates.

This work doesn't show that life never existed on Mars&emdash;only that the extraordinary claims made by David McKay and his fellow NASA scientists last August for the discovery of signs of ancient Martian life are probably incorrect, says Scott. "The search for ancient Martian life must go on," he adds, "but it shouldn't be focused on the carbonates in meteorite ALH84001."

Scott, Krot and Yamaguchi work on all types of meteorites in the Hawai'i Institute of Geophysics and Planetology (HIGP), which is part of the School of Ocean and Earth Science and Technology at the University of Hawai'i at M o(a,¯)noa. HIGP Director Klaus Keil is the principal investigator of the NASA grant that supported the work by Scott and his colleagues on the Martian meteorites.

For more information about the research, visit Planetary Science Research, a Web magazine edited by UH researchers G. Jeffrey Taylor and Linda Martel, at www.soest.hawaii.edu/PSRdiscoveries/May97/ShockedCarb or see the May 22 issue of Nature on-line at www.america.nature.com.

-UH-




University of Hawai'i University Relations Media & Publications Honolulu, HI 96822	(808) 956-8856 Telephone (808) 956-3441 Facsimile ur@hawaii.edu E-Mail

For Immediate Release: Contact: Cheryl Ernst (808) 956-5941		May 22, 1997

New Findings by UH Scientists Challenge Report of Fossil Life from Mars UH researchers have discovered important evidence that counters the claims that a Martian meteorite contains signs of ancient life on Mars. The scientists' findings, announced last week, suggest that carbonates in the meteorite resulted from melted material created by a giant impact on Mars rather than from living organisms. Possible fossil Martian organisms were reported last August in carbonates in the meteorite ALH84001. UH scientists Ed Scott, Akira Yamaguchi and Sasha Krot say these carbonates and minerals in them were formed at high temperatures from melted material and could not have been formed by organisms. The scientists' paper, which appears in the May 22 issue of the journal Nature, provides evidence that the carbonates and two other minerals in the meteorite ALH84001 formed from melts during a large impact 4 billion years ago. The scientists used electron microscopes to analyze tiny grains of carbonate and silicates in fractures in the rock and compared what they found in the Martian meteorite with other meteorites that had experienced giant impacts. Scott and his colleagues infer that the impact melted tiny carbonates and squirted the melts into fractures in the rock. Within seconds the melts cooled and the cracks were squeezed tight, leaving tiny carbonates embedded inside the fractured rock. Two silicate minerals, feldspar and silica, melted simultaneously and squirted into cracks to form glasses next to the carbonates. This work doesn't show that life never existed on Mars&emdash;only that the extraordinary claims made by David McKay and his fellow NASA scientists last August for the discovery of signs of ancient Martian life are probably incorrect, says Scott. "The search for ancient Martian life must go on," he adds, "but it shouldn't be focused on the carbonates in meteorite ALH84001." Scott, Krot and Yamaguchi work on all types of meteorites in the Hawai'i Institute of Geophysics and Planetology (HIGP), which is part of the School of Ocean and Earth Science and Technology at the University of Hawai'i at M o(a,¯)noa. HIGP Director Klaus Keil is the principal investigator of the NASA grant that supported the work by Scott and his colleagues on the Martian meteorites. For more information about the research, visit Planetary Science Research, a Web magazine edited by UH researchers G. Jeffrey Taylor and Linda Martel, at www.soest.hawaii.edu/PSRdiscoveries/May97/ShockedCarb or see the May 22 issue of Nature on-line at www.america.nature.com.