Keep in mind that there are now some non-Vesta originating eucrites identified. So the pass state of knowledge holding that all HEDs were from Vesta should be qualified with a caveat that "Most all eucrites are from Vesta" or "with rare exception..." or "all most all..."
Elton On 5/11/12, Benjamin P. Sun <bpsun2...@gmail.com> wrote: > This is not a surprise to me... or to most of us. But it may be "news" > to some of you out there.. > > > http://www.jpl.nasa.gov/news/news.cfm?release=2012-132 > > https://asunews.asu.edu/20120510_Vesta > > "Data also confirm a distinct group of meteorites found on Earth did, > as theorized, originate from Vesta. The signatures of pyroxene, an > iron- and magnesium-rich mineral, in those meteorites match those of > rocks on Vesta's surface. These objects account for about 6 percent of > all meteorites seen falling on Earth. > > This makes the asteroid one of the largest single sources for Earth's > meteorites. The finding also marks the first time a spacecraft has > been able to visit the source of samples after they were identified on > Earth." > > “Dawn observations enabled us to recognize that there are actually TWO > large basins at the south pole, an older one named “Veneneia” and a > younger one named “Rheasilvia”,” explains Williams. > > The Rheasilvia basin dominates the geology of Vesta, as the basin > itself and its impact ejecta cover most of the southern hemisphere. > The center of Rheasilvia has a central peak taller than Mt. Everest or > Mauna Loa on Earth, similar in height to Olympus Mons on Mars. This > basin appears to have excavated into the mantle of Vesta, exposing > material spectrally similar to diogenite meteorites; Vesta’s crust is > spectrally similar to eucrite and howardite meteorites, thus > confirming that Vesta and its family of asteroids are the source of > the howardite-eucrite-diogenite (HED) family of basaltic achondrite > meteorites. > > “For most planets and moons we see the pictures first, then have > samples collected later to confirm our geologic interpretations. In > the case of Vesta, thanks to the HED meteorites, we have the samples > first, and must try to relate them to our emerging geologic picture of > Vesta from the Dawn mission,” > ______________________________________________ > > Visit the Archives at > http://www.meteoritecentral.com/mailing-list-archives.html > Meteorite-list mailing list > Meteorite-list@meteoritecentral.com > http://six.pairlist.net/mailman/listinfo/meteorite-list > ______________________________________________ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list