Re: [meteorite-list] New Met Bulletin Approvals - new Czech meteorites
Hi Gary, Yes, 20 years seems a bit short for W3. I know it rains a lot in Czech Republic -- more than Roosevelt County!, but here are some estimates of the terrestrial ages of the weathering grades taken from Wlotzka, F., Meteoritics, vol. 28, no. 3, volume 28, page 460-460: "A correlation between these weathering grades and the terrestrial ages was shown for meteorite finds from Roosevelt County, New Mexico [1]. In these climatic conditions the weathering grades W2 to W6 develop in the following times: W2, 5000 to 15,000 yr; W3, 15,000 to 30,000 yr; W4, 20,000 to 35,000 yr; W5 and W6, 30,000 to >45,000 yr. Similar terrestrial ages were found for chondrites of these weathering grades from the Lybian and Algerian Sahara [2,3]. Antarctic meteorite finds weather much more slowly. A check of 53 Antarctic ordinary chondrites (of hand specimen weathering categories A to C) showed only 9 of grade W2, the rest being W1. Among the W1s is ALHA77278 (category A) with a terrestrial age of 320,000 yr" Best regards, Carl Agee PS: we don't what the climate was like in Roosevelt Co. 30,000 years ago, maybe it was wetter too! Message: 1 Date: Tue, 21 Feb 2012 07:04:54 -1000 From: Gary Fujihara Subject: Re: [meteorite-list] New Met Bulletin Approvals - new Czech meteorites To: "Jan Woreczko - www.meteoritica.eu" Cc: meteorite-list@meteoritecentral.com Message-ID: <6e6a9f8f-96ef-43a4-bd5a-f4be936ce...@mac.com> Content-Type: text/plain; charset=windows-1252 Aloha Jan, >From just a cursory glance at the metbull entry for Benesov (a), I would >surmise a reason for the non-fall classification is due to the fact that much >time had elapsed from the witnessed fireball on May 7, 1991 and the actual >recovery of material on April 9, 2011. Because almost twenty years had >passed, there can be no assurance that the recovered pieces are associated >with the witnessed sightings. Additionally, Benesov (a) is an LL3.5 and Benesov (b) is an H5 and were found on the same day 250m apart, both with a weathering grade of W3. Characteristics are "Weathered fragments lacking fusion crust. The meteorites resemble the terrestrial stones and slag found in the field." To me, this implies that the recovered pieces have a terrestrial age greater than 20 years. gary On Feb 21, 2012, at 6:18 AM, Jan Woreczko - www.meteoritica.eu wrote: > Ha > Why are these findings are not classified as a falls? > > Bene?ov (a) http://www.lpi.usra.edu/meteor/metbull.php?code=54854 > Bene?ov (b) http://www.lpi.usra.edu/meteor/metbull.php?code=54855 > > http://translate.google.pl/translate?sl=pl&tl=en&js=n&prev=_t&hl=pl&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fwiki.meteoritica.pl%2Findex.php5%2FBene%25C5%25A1ov > > > Best wishes, > Woreczko > > __ > > 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 Gary Fujihara Big Kahuna Meteorites (IMCA#1693) 105 Puhili Place, Hilo, Hawai'i 96720 http://bigkahuna-meteorites.com/ http://shop.ebay.com/fujmon/m.html (808) 640-9161 -- Carl B. Agee Director and Curator, Institute of Meteoritics Professor, Earth and Planetary Sciences MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 Tel: (505) 750-7172 Fax: (505) 277-3577 Email: a...@unm.edu http://meteorite.unm.edu/people/carl_agee/ __ 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
Re: [meteorite-list] New Met Bulletin Approvals - new Czech meteorites
Ha There is no certainty, it is a fact. Perhaps Benesov meteorite had a double lithology, such as Almahata Sitta? The weathering grade W3 is not difficult to achieve in humid climates of Central Europe. Thank you for your response. Best Woreczko - Original Message - From: "Gary Fujihara" To: "Jan Woreczko - www.meteoritica.eu" Cc: Sent: Tuesday, February 21, 2012 6:04 PM Subject: Re: [meteorite-list] New Met Bulletin Approvals - new Czech meteorites Aloha Jan, From just a cursory glance at the metbull entry for Benesov (a), I would surmise a reason for the non-fall classification is due to the fact that much time had elapsed from the witnessed fireball on May 7, 1991 and the actual recovery of material on April 9, 2011. Because almost twenty years had passed, there can be no assurance that the recovered pieces are associated with the witnessed sightings. Additionally, Benesov (a) is an LL3.5 and Benesov (b) is an H5 and were found on the same day 250m apart, both with a weathering grade of W3. Characteristics are "Weathered fragments lacking fusion crust. The meteorites resemble the terrestrial stones and slag found in the field." To me, this implies that the recovered pieces have a terrestrial age greater than 20 years. gary On Feb 21, 2012, at 6:18 AM, Jan Woreczko - www.meteoritica.eu wrote: Ha Why are these findings are not classified as a falls? Benešov (a) http://www.lpi.usra.edu/meteor/metbull.php?code=54854 Benešov (b) http://www.lpi.usra.edu/meteor/metbull.php?code=54855 http://translate.google.pl/translate?sl=pl&tl=en&js=n&prev=_t&hl=pl&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fwiki.meteoritica.pl%2Findex.php5%2FBene%25C5%25A1ov Best wishes, Woreczko __ 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 Gary Fujihara Big Kahuna Meteorites (IMCA#1693) 105 Puhili Place, Hilo, Hawai'i 96720 http://bigkahuna-meteorites.com/ http://shop.ebay.com/fujmon/m.html (808) 640-9161 __ 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
Re: [meteorite-list] New Met Bulletin Approvals - new Czech meteorites
Aloha Jan, >From just a cursory glance at the metbull entry for Benesov (a), I would >surmise a reason for the non-fall classification is due to the fact that much >time had elapsed from the witnessed fireball on May 7, 1991 and the actual >recovery of material on April 9, 2011. Because almost twenty years had >passed, there can be no assurance that the recovered pieces are associated >with the witnessed sightings. Additionally, Benesov (a) is an LL3.5 and Benesov (b) is an H5 and were found on the same day 250m apart, both with a weathering grade of W3. Characteristics are "Weathered fragments lacking fusion crust. The meteorites resemble the terrestrial stones and slag found in the field." To me, this implies that the recovered pieces have a terrestrial age greater than 20 years. gary On Feb 21, 2012, at 6:18 AM, Jan Woreczko - www.meteoritica.eu wrote: > Ha > Why are these findings are not classified as a falls? > > Benešov (a) http://www.lpi.usra.edu/meteor/metbull.php?code=54854 > Benešov (b) http://www.lpi.usra.edu/meteor/metbull.php?code=54855 > > http://translate.google.pl/translate?sl=pl&tl=en&js=n&prev=_t&hl=pl&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fwiki.meteoritica.pl%2Findex.php5%2FBene%25C5%25A1ov > > > Best wishes, > Woreczko > > __ > > 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 Gary Fujihara Big Kahuna Meteorites (IMCA#1693) 105 Puhili Place, Hilo, Hawai'i 96720 http://bigkahuna-meteorites.com/ http://shop.ebay.com/fujmon/m.html (808) 640-9161 __ 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
