Birthplace of famous Mars meteorite pinpointed

[telfrow]

<b>12:21 16 September 2005 <br />NewScientist.com news service <br />David L Chandler</b><br /><br /><i>The original home of the world's most famous space rock, the Allen Hills Martian meteorite, has now been identified, thanks to data from the orbiting spacecraft Mars Global Surveyor and Mars Odyssey and a better understanding of cratering dynamics.<br /><br />The rock, called ALH84001, has been the subject of intense study ever since 1996 when scientists from NASA's Johnson Space Center startled the world by reporting that fossilised microbial life might be embedded inside it. The rock, which formed at the very dawn of the solar system 4.5 billion years ago, was blasted from the surface of Mars around 17 million years ago by an impact and made its way to Earth, landing in Antarctica.<br /><br />While the claim remains highly controversial, the JSC scientists say further study has bolstered the evidence for fossilised life in ALH84001. So the discovery of the rock's place of origin on Mars could make that spot a strong candidate for a future landing by robots or people searching for extraterrestrial life.<br /><br />The analysis, based on the rock's mineral characteristics, was presented by Vicky Hamilton of the University of Hawaii at this week's meeting of the Meteoritical Society in Tennessee, US.<br /><br />Perfect match<br /><br />Hamilton looked for matches between the laboratory spectrum of the meteorite, a mix of orthopyroxene and basaltic minerals, and data from the Thermal Emission Spectrometer and other instruments on the orbiters. "There was only this one place, in all the places we can look that aren't too dusty, that had a composition that was consistent with the ALH84001," Hamilton told New Scientist.<br /><br />The site is in the Eos Chasma, a branch of the enormous Valles Marineris canyon system. Hamilton has examined it further using topographic and thermal data and high-resolution imagery. "Putting this all together, it's all consistent with this being the sourc</i> <div class="Discussion_UserSignature"> <strong><font color="#3366ff">Made weak by time and fate, but strong in will to strive, to seek, to find and not to yeild.</font> - <font color="#3366ff"><em>Tennyson</em></font></strong> </div>

 

[dragon04]

Interesting. I'm pretty skeptical of being able to "pinpoint" where that meteorite came from, but I've always wondered if Valles Marineris was created by a huge impactor and further if that led to the decine of anything that resembled a biosphere on Mars. <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[telfrow]

I'm a bit skeptical as well, especially in light of the "disclaimer": "There was only this one place, <b>in all the places we can look that aren't too dusty</b>, that had a composition that was consistent with the ALH84001..." (Emphasis added.) <div class="Discussion_UserSignature"> <strong><font color="#3366ff">Made weak by time and fate, but strong in will to strive, to seek, to find and not to yeild.</font> - <font color="#3366ff"><em>Tennyson</em></font></strong> </div>

 

[bobw]

The last time I remember someone pinpointing the location it was an oval crater that could only have been formed by a low angle impact. They had pictures of the exact spot. I wonder what happened with that?<br /> <div class="Discussion_UserSignature"> </div>

 

[telfrow]

Bobw:<br /><br />I managed to find this pdf. Could this be what you mentioned? <br /><br />www.lpi.usra.edu/meetings/lpsc97/pdf/1661.PDF<br /><br /> <div class="Discussion_UserSignature"> <strong><font color="#3366ff">Made weak by time and fate, but strong in will to strive, to seek, to find and not to yeild.</font> - <font color="#3366ff"><em>Tennyson</em></font></strong> </div>

 

[bobw]

I'm pretty sure I read it in either Scientific American or Astronomy magazine. The article was far less detailed than the one you linked to in Lunar and Planetary Science. Thanks for that, by the way; and yes, the article I read could have been a report about your article or the conference. <br /><br />It makes me wonder what breakthrough has reduced the minimum circular crater size by 80% from 100 km in the LPS link (1997) to 20 km in the new study. That's practically a revolution!<br /><br />Just to clarify I hope nobody thinks that I am trying to argue about which site is the spot. I was just trying to make a joke. <div class="Discussion_UserSignature"> </div>