Its great that there is such a nice amount of this material when considering all the pairings... With over 10kg of this material in pairings known so far, I am willing to bet there is likely a good amount more still. I bet the Brachinties are coming out of the woodwork to be tested.
Greg Catterton www.wanderingstarmeteorites.com IMCA member 4682 On Ebay: http://stores.shop.ebay.com/wanderingstarmeteorites On Facebook: http://www.facebook.com/WanderingStarMeteorites --- On Tue, 10/5/10, John higgins <[email protected]> wrote: > From: John higgins <[email protected]> > Subject: [meteorite-list] Official Announcement NWA 6077 is Paired with NWA > 5400 > To: [email protected] > Date: Tuesday, October 5, 2010, 9:26 AM > Official Announcement > > NWA 6077 IS PAIRED WITH NWA 5400 > > North West Africa 6077 Description: > An olivine-rich assemblage with cumulate (or possibly > metamorphic) texture > exhibiting triple junction grain boundaries. Olivine > (Fa30.2-30.7), > orthopyroxene (Fs24.1-24.5Wo2.1-2.0), clinopyroxene > (Fs9.4-10.0Wo44.0-43.5), > altered kamacite, chromite, chlorapatite, Ni-bearing > troilite and/or pyrrhotite. > No plagioclase was found. Analysis conducted at the > Carnegie Institution of > Washington show that the oxygen isotopic composition of > this specimen plots on > the Terrestrial Fractionation Line. In conjunction with the > mineral compositions > and texture, this establishes that NWA 6077 is paired with > NWA 5400. > > The averages of the two Oxygen Isotope Results are: > d17O = 2.780, d18O = 5.358, D17O = -0.019 (all in per mil) > > This brachinite was recovered out of Morocco in 2008 as > one whole stone and > purchased by John Higgins. It was submitted for > classification to Dr. Tony > Irving and was given the provisional classification number > of NWA 6077. This > meteorite has a modest TKW of less than 1000g after the > type specimen was > removed. > > Personal Notes: Although I suspected that the two were > possibly paired due to > similarities in visual observations and classification > compositions, I felt it > was important to wait for secondary Oxygen Isotope results > to come in which have > recently confirmed the results beyond a reasonable doubt. > There was also another > important factor besides Oxygen Isotope testing that had > to be taken into > account. Orthopyroxene which is present in NWA 5400 was > missed the first time > around in NWA 6077 because it looks identical to > clinopyroxene in back-scattered > electron images. However further in-depth > microprobe studies of the thin section > have confirmed the presence of orthopyroxene, and are > now noted in the updated > description. I feel that making a self pairing based upon > my own > visual observations, is not only unethical, inappropriate, > and akin to pirating, > but would only feed the controversies regarding this > meteorite without the > scientific testing data to back up such speculation, such > action would be > premature, immoral and unfair to Greg Hupe and NWA 5400 > after all the time and > effort he put into the study of what has become one of the > most important > meteorite finds in history. > > Have a Great Day! > John Higgins > IMCA#9822 > > > > ______________________________________________ > Visit the Archives at > http://www.meteoritecentral.com/mailing-list-archives.html > Meteorite-list mailing list > [email protected] > http://six.pairlist.net/mailman/listinfo/meteorite-list > ______________________________________________ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list [email protected] http://six.pairlist.net/mailman/listinfo/meteorite-list
