Hello Mark, Stan and Everyone,First of all, in the last 24 hours I have "collected" way too many 'green laser', 'you are a millionaire', 'I got screwed by a Moroccan', 'I'm tired of Ssteevee' and other numerous other emails.
Anyway, here is the latest and most up to date abstract regarding NWA 2828 and other EL3 Fossil meteorites:
http://www.agu.org/cgi-bin/SFgate/SFgate?&listenv=table&multiple=1&range=1&directget=1&application=fm06&database=%2Fdata%2Fepubs%2Fwais%2Findexes%2Ffm06%2Ffm06&maxhits=200&="P51E-1247";Just by chance that Mark mentioned this EL3 today, I loaded a couple dozen NWA 2828 EL3 Fossil meteorite slices and complete stones on eBay "yesterday" under my seller name, NaturesVault. For those of you who would like to see many different specimens featuring distinct "chondrules", the discovery in some NWA 2828 material after initial analysis which is why the classification went from aubrite to EL3. We have been collectiing and studying this material for over a year and a half so the scientists have a good picture of why this meteorite is so confusing and different. Bottom line, the darker the material, the more weathered., but cool all the same.
Here are some photos of chodrules and other features of NWA 2828: Photograph of a 24.9g NWA 2828 slice with rhyolite pebble (image 1): http://www.lunarrock.com/nwa2828/nwa2828pebble.jpg Photograph of magnified radial pyroxene chondrule (image 2): http://www.lunarrock.com/nwa2828/nwa2828chondrule.jpg Photograph of magnified whitish enstatite-rich clast (image 3): http://www.lunarrock.com/nwa2828/nwa2828clast.jpg Photograph of a 14.3g complete slice of NWA 2828 (image 4): http://www.lunarrock.com/nwa2828/nwa2828slice.jpg Here is the abstract again in case the link does not work:EL3 Chondrite (not Aubrite) Northwest Africa 2828: An Unusual Paleo-meteorite Occurring as Cobbles in a Terrestrial Conglomerate
AU: * Kuehner, S M EM: [EMAIL PROTECTED]AF: Dept. of Earth and Space Sciences, University of Washington, Seattle, WA 98195 United States
AU: Irving, A J EM: [EMAIL PROTECTED]AF: Dept. of Earth and Space Sciences, University of Washington, Seattle, WA 98195 United States
AU: Bunch, T E EM: [EMAIL PROTECTED]AF: Dept. of Geology, Northern Arizona University, Flagstaff, AZ 86011 United States
AU: Wittke, J H EM: [EMAIL PROTECTED]AF: Dept. of Geology, Northern Arizona University, Flagstaff, AZ 86011 United States
AU: Hupé, G M EM: [EMAIL PROTECTED]AB: Although we recently classified NWA 2828 as an aubrite [1], our examination of new material (now comprising over 120 stones totaling >27 kg) requires revision of that classification. New information on the find site in Algeria indicates that these stones were excavated from a subsurface deposit, and we have found terrestrial rhyolite pebbles and sandy matrix attached to several NWA 2828 stones (see images at http://www.ess.washington.edu/meteoritics). Thus this is a rare example of a paleo-meteorite or 'fossil' meteorite. Some stones contain sparse (<5 vol.%) but very distinct round, radial pyroxene chondrules (up to 3 mm across), as well as rounded, fine-grained aggregates (up to 6 mm across) rich in either enstatite or sodic plagioclase. Remnant Na-Al-Si-rich glass is present within cavities in chondrules, both between enstatite blades and in annular zones. The matrix contains pervasive 0.2-0.5 mm cavities with coatings of calcite and minor halite and gypsum. Iron sulfate (after troilite), jarosite, an inhomogeneous (possibly amorphous) phase rich in Fe, Cr, Si, Ca, Ti, P, S and Cl, minor native sulfur and silica also are present, and brown Fe-rich rinds on one stone contain up to 6.5 wt.% Ni. These secondary minerals signify terrestrial alteration of primary metal, sulfides, phosphides, nitrides and glass in an ancient fluvial and/or acidic lacustrine environment. The dominant primary phase in NWA 2828 is enstatite (En98.4Wo1.4), which forms stubby prismatic grains (lacking polysynthetic twinning indicative of inverted clinoenstatite [cf., 1]). Our original classification was based on a very small specimen of an apparently igneous-textured rock, but the discovery of chondrules and the absence of twinned enstatite now suggests that it is instead an unequilibrated enstatite chondrite. Additional primary phases noted previously [1] are sodic plagioclase (An14- 15Or3-4), troilite, graphite, daubreelite, alabandite, oldhamite, schreibersite, glass and very rare kamacite. The well-formed, round chondrules containing glass coupled with the unrecrystallized matrix lead us to re-classify NWA 2828 as an EL3 chondrite. We also must revise our opinion [1] about the relationship between NWA 2828 and material classified as EL chondrites NWA 2965 and NWA 2736, which evidently come from the more extensively weathered top of the same ancient conglomerate layer as NWA 2828. [1] Irving A.J. et al. (2006) 69th Met. Soc. Mtg., &35;5264 (MAPS 41 Suppl., A84)
DE: 1028 Composition of meteorites (3662, 6240) DE: 3662 Meteorite mineralogy and petrology (1028, 6240) DE: 6240 Meteorites and tektites (1028, 3662) SC: Planetary Sciences [P] MN: 2006 Fall Meeting -------------------------------------------------------------------------------- New Search I hope this helps with this difficult as well as educating classification. Best regards, Greg ==================== Greg Hupe The Hupe Collection NaturesVault (eBay) [EMAIL PROTECTED] IMCA 3163 ====================----- Original Message ----- From: "MARK BOSTICK" <[EMAIL PROTECTED]>
To: <meteorite-list@meteoritecentral.com> Sent: Friday, December 01, 2006 2:56 PMSubject: Re: [meteorite-list] Stan's NWA 2965 EL6/7 and achondrite vs chondrite
Hello Stan, You noted, "the classification of this stuff as a 6/7 is SO 5 minutes ago. it's an EL3..."Would it not be fair to say it is an EL6/7 with EL3 clasp material and mostof the material is the EL6/7? I have made a comment or two on this before,recently with Dimmitt, that I do think it is right to give a meteorite with more then one petro type the 3 number, when it is not the dominating matrix.This is more because of the commercial aspect then the scientific aspect. Usually a meteorite with a 3 will sell for several times what a 5-6 sells for. Then again, I guess petro 3 chondrites don't command the dollar they did 5 years ago, so maybe this doesn't matter to anyone other then me. I would hate to see some future scientist or student grab an L5 piece of NWA 869 and an H5 part of Dimmitt and create some paper of type 3 chondrites.On NWA 2965, or whatever name is eventually gets I was pretty much ignoring the classification as I am not sure how final the EL3 is, or more so, how itwill appear in the Met. Bul. So I guess I like what Weir has labeled the meteorite. (http://www.meteoritestudies.com/protected_NWA2965.HTM)"The light grey/blue lithology material - while typically referred to as the'fresher' material by Moroccan sources is apparently the more aqueously altered of the two lithologies." Interesting, I would have guessed along with the Moroccan dealers. Especially since you do not see the oxidized metal veining in the lighter material. Maybe I should run my larger slice under water for a couple days...;^) Thanks for the neat auction. I will be giving away the pieces I accidently broke off shortly and trying to sell the meteorite next week at half price....just joking. Clear Skies, Mark Bostick Wichita, Kansas www.meteoritearticles.com www.kansasmeteorites.com www.imca.cc ______________________________________________ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
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