30 August 2000
CHICAGO -- Analysis of new Martian meteorites is confounding planetary scientists with clues that simply don't add up.
Rather than clearing up existing questions about the Red Planet, results from the new meteorites seem to be opening up a Pandora's box of questions about Mars. Evidence from the rocks doesn't seem compatible with one of the most trusted scientific conclusions about the planet: that the vast majority of the Martian surface is billions of years old.
The puzzle came into sharp focus here this week at the annual meeting of the Meteoritical Society, as scientists announced their findings from three recently discovered Mars rocks.
The Los Angeles meteorite, which was discovered last fall by a Los Angeles rock hunter, was revealed to be only 175 million years old -- contemporary in geologic terms. It is a volcanic rock that crystallized from magma near the Martian surface. Larry Nyquist and a research team at NASA's Johnson Space Center and Lockheed Martin in Houston determined the age by measuring the state of certain weakly-radioactive isotopes within the meteorite.
Full story here.
Aug. 30, 2000 -- Meteors that would be little more than a flash in the sky on Earth can cause massive explosions, vast dust storms and giant lightning bolts on Mars, say Russian scientists. By adapting some classified Cold War equations created to predict what nuclear blasts would do in Earth's atmosphere, scientists from the Russian Academy of Sciences Institute for Dynamics of Geospheres think they have a way of predicting how meteors would behave when they bust through the thin martian atmosphere.
Full story here.
TSE - THE SPACE EXPERIENCE
Fenruary 4, 2000
I'm very pleased to report on a new Mars meteorite find by a good friend and fellow meteorite collector, Bob Verish. The meteorite was found somewhere in the Mojave Desert in California, and consists of two stones of 452.6 & 245.4 grams. The two rocks have been classified as Mars meteorites, specifically basaltic shergottites, by analysis done at UCLA. The new meteorite's official name is the Los Angeles meteorite.
The rocks were stored in boxes in Bob's backyard along with a large portion of his rock collection. On Oct. 30, 1999, while clearing out his rock collection for rat nests and rodent dropping, Bob came across the rocks again. Since Bob had begun collecting meteorites about 5 years ago, he knew what meteorites looked like. He immediately noted the dark fusion crust on the rocks and suspected the two rocks to be meteorites. Bob cut off small samples of each rock (total weight of about 30 grams) which he would then take to Alan Rubin at UCLA for analysis.
Per Bob Verish , the following paragraph is a proposed draft of what is proposed to appear in the Meteoritical Bulletin 84: Final version, 2000, July, MAPS 35:
Los Angeles (original find location unknown)
Los Angeles County, California, USA
Recognized 1999 October 30
Martian basalt (shergottite)
Two stones, weighing 452.6 g and 245.4 g respectively, were found by Bob Verish in his back yard while he was cleaning out a box of rocks that was part of his rock collection. The specimens may have been collected ~20 years ago in the Mojave Desert. Classification and mineralogy (A. Rubin, P. Warren and J. Greenwood, UCLA): a basalt with a texture closely resembling that of the QUE 94201; plagioclase laths, 43.6 vol%, An41Or4 to An58Or1, have been shocked to maskelynite; Ca-pyroxene, 37.7 vol%, ranges from Fs45Wo13 to Fs45Wo37 to Fs72Wo24; other mineral modes, 4.9 vol% silica, 4.2 vol% fayalite, 2.4 vol% K-rich felsic glass, 3.5 vol% titanomagnetite, 2.7 vol% Ca phosphate (including whitlockite and chlorapatite), 0.7 vol% pyrrhotite, and 0.2 vol% ilmenite; contains a higher proportion of plagioclase than Shergotty or Zagami, and has pyroxene that is moderately more ferroan than that in QUE 94201. Specimens: main masses with finder; 30 g, UCLA. [Houston LPSC references to be added later]
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Max Planck Institute for Chemistry
Several observations make this finding exciting news and are an enrichment of meteoritical sciences. This meteorite is the first Martian meteorite found in the hot desert climate of the Sahara. It is the first one found since 1994 and also the first since the discussion whether there is life on Mars began two years ago. Now, the number of Martian meteorites has increased to a total of 13, a small number if compared to the total of more than 20,000 meteorite specimens known so far. A fragment of the meteorite was given to the Max Planck Institute for Chemistry in Mainz by a private finder for scientific purposes. The rock weighs a little over 2 kg and is shaped like a loaf of bread.
During a five-minute speech, Zipfel presented results from inert gas, chemical and mineralogical studies. The inert gas inventory of the atmosphere of Mars is very characteristic and well known from the Viking mission measurements on the surface of Mars in 1976. This is, so far, the strongest evidence that meteorites having this inert gas fingerprint must come from Mars. Inert gases present in this meteorite clearly puts it in the group of Martian meteorites. Typical elemental ratios obtained by bulk chemical analyses of a chip of the new meteorite soon confirmed this finding. In addition, mineral chemistry and petrographic observations, such as the presence of feldspathic glass, rounded out the picture. 'We had no doubt that this was a Martian meteorite,' said Zipfel, who made the announcement at the MSM in Dublin.
During the meeting, Zipfel gave British scientists from the Open University a 150 mg sample for analysis of the oxygen isotopic composition of the meteorite. These measurements were carried out one week after the Dublin announcement and their results are consistent with findings obtained by the Max Planck scientists.
Inert gas analyses show that this meteorite was ejected from Mars about 1 million years ago, marking an ejection event unknown from other Martian meteorites, said Zipfel in her presentation. After that, the meteorite took its time to travel through space before it was captured by the gravity of the Earth and landed in Northern Africa. It was collected there in May of this year and immediately brought to the German Max Planck Institute for classification. The meteorite is the first find of its group in a hot desert environment. Clearly, it carries along with it its desert history, in that it is penetrated throughout by veins filled with terrestrial weathering products. 'The search for past evidence of life in this meteorite will be severely impeded because it was lying in the hot desert for probably thousands of years and not in a relatively sterile environment such as Antarctica', said Zipfel. However, it will give scientists the opportunity to gain further knowledge about geochemical processes on Mars and new insights into its evolution as a planet.
The chemical study of Martian meteorites and their implications for the bulk composition of Mars has a long tradition with scientists from the Max Planck Institute for Chemistry in Mainz. Their development of the APXS instrument was selected by NASA's Mars "Pathfinder Mission". Measurements with this instrument made it possible for the first time to analyse rocks sitting on the surface of Mars.
Bread-loaf shape of the new Martian meteorite. Clearly visible the sandblown surface crosscut by cracks.
Two images showing the sample given to the Open University are available at http://psri.open.ac.uk/News/NewMarsIMAGES.html. Below are the image captions:
150mg of the new martian meteorite was made available for analyses at the PSRI [Planetary Sciences Research Institute]. This is shown on the small square of foil on the left of the image. A one pound coin (22mm diameter) is shown for scale. Less than 1% of this material is used for an oxygen isotope analysis.
A close up of the largest chip above (top left corner of the foil square) is shown below. The chip is approximately 5mm across.
Planetary Science Research Institute
10th AUGUST 1998
If authenticated, it could provide the next breakthrough in the search for evidence of life on the red planet and will almost certainly make its prospector finder a millionaire.
Out of the worldwide collection of 20,000 meteorites, only 12 have been proven to come from Mars. All of the dozen are owned by museums or the US Government. The meteorite being analysed by the Open University was found in the Sahara Desert by a private prospector who, if his find is proved genuine, stands to earn US$1000 (or 620 English pound) a gram on the commercial market from the 2.2kg rock.
The Sahara Desert find was announced at a Meteoritical Society conference in Dublin last week. A specimen was despatched immediately to the Planetary Sciences Research Institute (PSRI) at the Open University who are able perform the definitive test of authenticity, a sort of geochemical version of DNA typing involving oxygen isotopes.
The experiment involves heating a sample with pulses of a laser beam in the presence of fluorine containing gas to displace oxygen from the silicate for measurement in a mass spectrometer.
There is global scientific interest in the test results. An affirmative report would pave the way for further analysis that could unlock the secrets of Martian climatic history and provide evidence of conditions capable of supporting life.
PSRI are the UK's leading research group on meteorites and Mars. They are championing the idea of Beagle 2, a British-built robot explorer that would be flown to Mars in 2003, carry out soil and rock analysis on the planet surface and transmit data back to Earth.
Beagle 2 is being designed by an international consortium led by the Open University's Professor Colin Pillinger, and a full-scale model of the lander vehicle will be on display at Monday's media conference. Further information about the Beagle 2 project is available from the Web site at http://beagle2.open.ac.uk.
(150mg of the new martian meteorite was made available for analyses at the PSRI. Less than 1% of this material is used for an oxygen isotope analysis.)
4 Aug 1998
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