[meteorite-list] AD > Tirhert (Foum El Hisn) on ebay !
Hello List Members, I added some fragments (including crust) of Tirhert on ebay. There won't be much more from me so go get them before it's too late ;-) http://www.ebay.com/sch/moky99/m.html Pierre-Marie Pelé Meteor-Center Météorites : achat - vente - expertise - expéditions - recherche http://www.meteor-center.com IMCA 3360 __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://three.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Tirhert is official - Met Bulletin Update
Hi Bulletin Watchers, The recent Tirhert eucrite fall is officially approved. Link : http://www.lpi.usra.edu/meteor/metbull.php?code=60285 Write-up : Tirhert28.935°N, 8.905°W Guelmim-Es-Semara, Morocco Fell: 2014 Jul 9 Classification: HED achondrite (Eucrite, unbrecciated) History: (H. Chennaoui Aoudjehane, A. Aaronson, M. Aoudjehane, A. Bouferra, A. Bouragaa) On Wednesday, 9 July 2014 around 9:30 pm, residents of Tirhert, Foum El Hisn, Douar Imougadir and nearby villages in southern Morocco, witnessed an intense fireball moving horizontally in a NW to SE direction and lasting about 4 s, shortly followed by multiple sonic booms. The fireball was seen by people from cities and villages more than 220 km around the fall site near Tirhert. Immediately following the fireball event the mayor and the authorities of the area organized a field search with police to check for possible security problems. The first meteorites were recovered the following day close to the road between Foum El Hisn and Assa. Thousands of people moved to the site from surrounding cities and villages to search, but many soon left because of the difficulties of searching during the hot 50°C daytime temperatures. The positions of many of the pieces were recorded from eyewitness testimonials, forming a roughly 6 × 3 km strewnfield trending NW to SE. The largest recorded mass around 1300 g was collected close to Tirhert at the coordinates listed for this entry. Recovered pieces weighed from 1 to 1300 g, with an estimated total mass of 8 to 10 kg. Most pieces are covered by a very shiny, black fusion crust. Physical characteristics: Glassy black fusion crust with translucent patches revealing plagioclase grains beneath. Broken surface shows mm-size white plagioclase and honey brown pyroxene grains, also some scattered mm-size opaque grains. Friable. Petrography: (C. Agee and N. Muttik, UNM) Microprobe examination of a polished mount shows texturally equilibrated pyroxene and plagioclase, granoblastic to poikilitic with many triple junctions. Pyroxenes show exsolution lamellae. Plagioclase and pyroxene grain size up to ~1-2 mm. Silica, ilmenite, chromite, troilite, and Fe-metal (low Ni) present. Fusion crust ~50-100 μm thick, vesicles up to 20 μm present, glassy with compositional gradients and swirls. (A. Irving, UWS) Optical petrographic examination of a thin section of a different specimen shows that it is composed of subequal amounts of pyroxene and twinned plagioclase with accessory opaque oxides and minor troilite. The overall texture is equigranular, but plagioclase occurs as aggregates of multiple subgrains, and some plagioclase contains clusters of tiny pyroxene inclusions. Magnetic susceptibility: Log χ = 2.53 Geochemistry: (C. Agee and N. Muttik, UNM) Low-Ca pyroxene Fs53.6±4.8Wo9.3±5.9, Fe/Mn=32±1, n=29; augite Fs30.3±1.3Wo39.2±1.0, Fe/Mn=33±2, n=15; plagioclase An89.9±0.9Ab9.6±0.9Or0.4±0.1, n=7. Fusion crust, proxy for bulk composition (mean value from EMPA with 20 μm beam) SiO2=48.25±0.99, TiO2=0.54±0.17, Al2O3=12.15±3.48, Cr2O3=0.22±0.04, FeO=19.32±2.82, MnO=0.58±0.09, MgO=7.72±1.21, CaO=10.09±1.14, Na2O=0.44±0.12 (all wt%), Mg#=41.6±0.5, n=23. Oxygen isotopes (Karen Ziegler, UNM): six acid-washed aliquots of bulk sample (1.3, 1.3, 2.4, 1.6, 1.7, 1.4 mg) analyzed by laser fluorination gave, respectively, δ17O = 1.524, 1.474, 1.106, 1.451, 1.286, 1.314, δ18O = 3.415, 3.233, 2.588, 3.268, 2.866, 2.961, Δ17O = -0.279, -0.233, -0.260, -0.275, -0.227, -0.249 (linearized, all permil). Classification: Achondrite (unbrecciated gabbroic eucrite). Highly equilibrated with clear compositional separation of the low and high calcium pyroxenes consistent with type 6 eucrites (Takeda and Graham, 1991). Specimens: 14 g at FSAC (0.6 g provided by A. Bouferra, 13.4 g provided by Aaronson); 41.4 g including a probe mount at UNM; 9 g including one polished thin section at UWB; 64.4 g in total for type specimens, and 72 g at ASU. Main masses are held by Aaronson and various private collectors. A. Habibi provided 25 g to UNM. -- - Web - http://www.galactic-stone.com Facebook - http://www.facebook.com/galacticstone Twitter - http://twitter.com/galacticstone Pinterest - http://pinterest.com/galacticstone - __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://three.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Stardust Team Reports Discovery of First Potential Interstellar Space Particles
August 14, 2014 Stardust Team Reports Discovery of First Potential Interstellar Space Particles Seven rare, microscopic interstellar dust particles that date to the beginnings of the solar system are among the samples collected by scientists who have been studying the payload from NASA's Stardust spacecraft since its return to Earth in 2006. If confirmed, these particles would be the first samples of contemporary interstellar dust. A team of scientists has been combing through the spacecraft's aerogel and aluminum foil dust collectors since Stardust returned in 2006.The seven particles probably came from outside our solar system, perhaps created in a supernova explosion millions of years ago and altered by exposure to the extreme space environment. The research report appears in the Aug. 15 issue of the journal Science. Twelve other papers about the particles will appear next week in the journal Meteoritics & Planetary Science. "These are the most challenging objects we will ever have in the lab for study, and it is a triumph that we have made as much progress in their analysis as we have," said Michael Zolensky, curator of the Stardust laboratory at NASA's Johnson Space Center in Houston and coauthor of the Science paper. Stardust was launched in 1999 and returned to Earth on Jan. 15, 2006, at the Utah Test and Training Range, 80 miles west of Salt Lake City. The Stardust Sample Return Canister was transported to a curatorial facility at Johnson where the Stardust collectors remain preserved and protected for scientific study. Inside the canister, a tennis racket-like sample collector tray captured the particles in silica aerogel as the spacecraft flew within 149 miles of a comet in January 2004. An opposite side of the tray holds interstellar dust particles captured by the spacecraft during its seven-year, three-billion-mile journey. Scientists caution that additional tests must be done before they can say definitively that these are pieces of debris from interstellar space. But if they are, the particles could help explain the origin and evolution of interstellar dust. The particles are much more diverse in terms of chemical composition and structure than scientists expected. The smaller particles differ greatly from the larger ones and appear to have varying histories. Many of the larger particles have been described as having a fluffy structure, similar to a snowflake. Two particles, each only about two microns (thousandths of a millimeter) in diameter, were isolated after their tracks were discovered by a group of citizen scientists. These volunteers, who call themselves "Dusters," scanned more than a million images as part of a University of California, Berkeley, citizen-science project, which proved critical to finding these needles in a haystack. A third track, following the direction of the wind during flight, was left by a particle that apparently was moving so fast -- more than 10 miles per second (15 kilometers per second) -- that it vaporized. Volunteers identified tracks left by another 29 particles that were determined to have been kicked out of the spacecraft into the collectors. Four of the particles reported in Science were found in aluminum foils between tiles on the collector tray. Although the foils were not originally planned as dust collection surfaces, an international team led by physicist Rhonda Stroud of the Naval Research Laboratory searched the foils and identified four pits lined with material composed of elements that fit the profile of interstellar dust particles. Three of these four particles, just a few tenths of a micron across, contained sulfur compounds, which some astronomers have argued do not occur in interstellar dust. A preliminary examination team plans to continue analysis of the remaining 95 percent of the foils to possibly find enough particles to understand the variety and origins of interstellar dust. Supernovas, red giants and other evolved stars produce interstellar dust and generate heavy elements like carbon, nitrogen and oxygen necessary for life. Two particles, dubbed Orion and Hylabrook, will undergo further tests to determine their oxygen isotope quantities, which could provide even stronger evidence for their extrasolar origin. Scientists at Johnson have scanned half the panels at various depths and turned these scans into movies, which were then posted online, where the Dusters could access the footage to search for particle tracks. Once several Dusters tag a likely track, Andrew Westphal, lead author of the Science article, and his team verify the identifications. In the one million frames scanned so far, each a half-millimeter square, Dusters have found 69 tracks, while Westphal has found two. Thirty-one of these were extracted along with surrounding aerogel by scientists at Johnson and shipped to UC Berkeley to be analyzed. NASA's Jet Propulsion Laboratory, Pasaden
[meteorite-list] Meteorite Picture of the Day
Today's Meteorite Picture of the Day: Pultusk Contributed by: Natural History Museum of Vienna http://www.tucsonmeteorites.com/mpodmain.asp __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://three.pairlist.net/mailman/listinfo/meteorite-list
