Geologists from Bern University and from the Natural History MuseumBern have found more than 180 meteorites in Oman in January/February2001. The most exciting find is a piece of Mars rock. This meteorite justreceived its name: Sayh al Uhaymir 094. Contrary to other finds of Marsmeteorites in deserts, this meteorite is fully available to science. Detailedinvestigations are currently under way at Bern University and atcollaborating institutions.
Just 18 meteorites from Mars are known today. Some have been fragmentedduring their fall. Sayh al Uhaymir 094 is a fragment of the 16th known Marsmeteorite. The geologic past of Mars, including the fate of water, as well asthe search for evidence of possible past life on Mars are research areas inwhich Mars meteorites play a key role. Meteorites from the red planet areof extreme scientific value because they are the only solid material availablefor about 10 years to come. If all goes well, about 500 g of Mars sampleswill then be returned to Earth at very high costs by spacecraft.
Sayh al Uhaymir 094: a window into Mars’s past
SaU 094 is, besides the antarctic finds, the only Mars meteorite fullyavaialable to science. Applying modern analytical tools at Bern University,the mineralogical characterization was possible using tiny fragments. Thenature of the minerals as well as their chemical composition clearlydemonstrate that SaU 094 is a Mars meteorite. It is a piece of rock that wasformed from molten lava, similar to volcanic rocks on Earth. The originfrom Mars is supported by measurements of oxygen isotopes (Ian Franchi,Open University, UK). Using X-ray tomography at EMPA, Dübendorf(Switzerland), the interior of the rock was investigated nondestructively.
An interesting result of this investigation is the occurrence of many cavitiesup to several millimetres in size, probably an effect of intense mechanicalstress during ejection from Mars. For detailed analyses samples will be cutfrom this stone. The majority of these analyses (mineralogy, chemicalcomposition, noble gases, age determination etc) will be conducted at BernUniversity. The availability of SaU 094 provides a new focal point for SwissMars science.
Why are so many meteorites found in Oman? Meteorite falls are very rare.Only where the surface of the Earth remains undisturbed and dry for verylong times meteorites accumulate over thousands of years. Enrichments ofthis type were first detected in Antarctica and since about 10 years desertsare being searched for meteorites systematically. From the Sahara about2000 meteorites are known already. The Sultanate of Oman has becomeknown as an important collection area for meteorites just in the past twoyears. It is spectacular that in this short time six Lunar and two Martianmeteorites have been found in Oman. All meteorite searches so far havebeen conducted without permission from the Omani authorities.
The meteorite Sayh al Uhaymir 094 was published in the MeteoriticalBulletin on may 23, 2001. The official text from the Bulletin is given below:
THE METEORITICAL BULLETIN
Announcement 85-5, May 23, 2001
Jeffrey N. Grossman, Editor ([email protected])
Jutta Zipfel, Co-editor for Saharan Meteorites([email protected])
Sayh al Uhaymir 094 20°59,469‘N 57°20,326‘E
Found 2001 February 8
Martian meteorite (shergottite)
A 223.3 g partially crusted stone was found in the same area as Sayhal Uhaymir 005, 008, and 051 by Marc Hauser and Lorenz Moser (Bern)during a search for meteorites. All samples may be paired. Mineralogyand classification (E. Gnos, Institute for Geological Sciences, Bern)and B. Hofmann (NMB): the grey-greenish rock shows a gabbro-liketexture and contains phenocrysts of olivine (average maximumdimension = 1.5 mm) displaying shock-twinning, mosaicism, and,locally, oxidation; optically clear parts of olivines (Fo65-69) occurin a fine-grained (average maximum grain size = 0.3 mm) groundmassconsisting of maskelynite (An55-64Or5-9) and pigeonite (En60-68Wo7-9)with minor augite, chromite and pyrrhotite; partially recrystallizedveins and pockets of shock-melted glass containing vescicles areabundant; x-ray tomography revealed that the specimen containsapproximately 0.4 vol% of pores up to 3 mm in size; shock stage, S5;weathering grade, W1; small rusty pockets are Fe-hydroxidereplacements of an unknown pre-existing phase. Specimens: all in NMB.
The red planet exerts great fascination to humans since antiquity. What isthe justification, however, to investigate such a distant object in detail? Thehistory of planet Earth can only be understood in context with the commonorigin with other planets and with the sun 4600 million years ago. From allthe planets Mars is most earthlike. There is evidence indicating that bothplanets developped in a similar way for the first 1000 million years, a timeduring which life established itself on Earth. The recent recognition ofextreme environments of life on Earth, e.g. in submarine springs at 110°Cand in porous rocks several kilometers below the surface demonstrates thatEarly Mars most likely offered environments prone for life.
18 Meteorites are the only objects from planet Mars currently available.Every piece provides new insight into the origin and development of ourneighbour planet. Additionally, meteorites represent potential “spaceships”for microbes. Detailed studies of all processes affecting meteorites duringtheir journey yields answers to the question of whether interplanetary transferof microbes is a likely process.
How are Mars meteorites delivered to Earth?
Fragments of planet Mars are naturally delivered to Earth. Impacts of largemeteorites on Mars produce craters. Rocks close to craters may be ejectedwith high velocity. To escape the gravity field of Mars, a velocity of at least5 km per second (approx. 20’000 km/h) is necessary. Ejected rock fragmentsmay approach Earth after millions of years, enter the atmosphere, and endup as a piece of rock in the desert. Research on Mars meteorites (e.g. at theInstitute of Physics of Bern University) demonstrates that the transferbetween Mars and Earth took between 0.7 and 20 million years for differentmeteorites.
Mars research: International efforts
Since the announcement of possible traces of life in the antarctic Marsmeteorite ALH84001 in 1996 Mars research has boomed. Even though thearguments presented in 1996 are hardly taken as solid evidence today, thisand consecutive studies have initiated a new era of Mars research pushing,among other things, the foundation of the NASA Astrobiology Institute(NAI). In Europe the European Astrobiology Network was founded in May2001.
New Mars meteorites were found in increasing rates in the last years, andseveral missions to Mars (some successful, others not) were undertaken.One mission (Mars Odyssey 2001) is currently on the way to Mars. Threemissions will attempt to reach Mars in december 2003 and january 2004,among them ESA’s Mars Express with the lander Beagle2. NASA’s MarsGlobal Surveyor is orbiting Mars since 1997 and is providing a wealth ofnew data about the Martian surface.
Mars research in Switzerland
Different scientific institutions are busy with Mars research also inSwitzerland. Mars meteorites are being studied since many years in thegroup of Prof. O. Eugster at Bern University. Here noble gas contents aremeasured, allowing a determination of the time the meteorite was exposedto the space environment, and with that, the ejection age from Mars. AtETH Zurich rare isotopes are being determined in Mars meteorites. For theMars lander Beagle2 the Swiss electronics/microtechnics company CSEMin Neuchâtel provides the cameras for panoramic, close-up and microscopicimaging. In collaboration with CSEM test images of terrestrial materialsare being made at the Natural History Museum Bern. There will be a pressorientation about the involvement of CSEM in the Beagle2 mission on June15, 2001 at 16.00 in Neuchâtel (see link in website).
The science team
Bern University conducts intensive research in the Sultanate of Oman sincemore than 30 years and has made a significant contribution to thedevelopment of this modern state. Besides geological mapping andprospection for raw materials, research was mainly focused on subjectslike origin of the Oman Mountains, palaeoclimate and ground waterresources. Students from Oman are integrated in ongoing projects andreceive training at Bern University. Many of these projects were supportedby the Swiss National Science Foundation. Thanks to these longstandinggood relations with the Sultanate of Oman, the first official meteorite searchproject could be realized in January/February 2001.
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