AW: [meteorite-list] LL7 Chondrites

From: Jörn Koblitz <koblitz_at_meteoritecentral.com>
Date: Thu Apr 22 10:32:54 2004
Message-ID: <E5E6112EA31FA24CB448E091C6883C05179FA5_at_server2000.microfab.de>

Here's a list of chondrites classified as LL7, the most recent ones not =
included. There are a some more Yamato finds that are listed without any =
petrologic type, since they are highly metamorphic - may be impact =
melts. Hard to classify, petrologically.

Best regards,
Joern
MetBase

name class country fall? date TKW kg fa_avg fs_avg
ALH 84027 LL7(?)Antarctica N 1984 0,008 27 23
Crocker's Well LL7 Australia N 1956 0,0038 29.8=09
Dar al Gani 1022 LL7 Libya N 2001/04/25 0,0336 29.6 25.0
Dhofar 011 LL7 Oman N 1999/12/05 0,15 30.5 25.5
Dhofar 014 LL7 Oman N 2000/01/21 0,414 29.7 24.3
EET 92012 LL7 Antarctica N 1992 0,002 30 24
EET 92013 LL7 Antarctica N 1992 0,0099 30 24
EET 92016 LL7 Antarctica N 1992 0,0101 30 24
NWA 503 LL7 ? N 2000 0,596 30.6=09
Sahara97037 LL7 ? N 1997/02 0,149 31.2 26.6
Uden LL7 Netherlands Y 1840/06/12 0,71 29.5 24.5
Y 74160 LL7 Antarctica N 1974/12/08 0,0314 29.4 23.1
Y 790144 LL7 Antarctica N 1979 0,09232 27.8 22.8
Y 791067 LL7 Antarctica N 1979 0,23459 31.0 24.8
Y 82067 LL7 Antarctica N 1982/12 0,01468 30.4 25.0


> -----Urspr=FCngliche Nachricht-----
> Von: Jeff Grossman [mailto:jgrossman_at_usgs.gov]
> Gesendet: Freitag, 26. M=E4rz 2004 01:07
> An: meteorite-list_at_meteoritecentral.com
> Betreff: Re: [meteorite-list] LL7 Chondrites
>=20
>=20
> One of the reasons that type 7 ordinary chondrites are rare=20
> may be that=20
> many researchers do not think the distinction between 6 and 7 is=20
> significant and therefore never classify anything as type 7. =20
> As far as=20
> anymeteorite called type "6/7" is concerned, don't forget=20
> that the slash in=20
> a classification often means "I can't decide" and not=20
> "transitional". Certain classifiers use lots of slashes and=20
> others never=20
> use them at all.
>=20
> jeff
>=20
> At 04:30 PM 3/25/2004 -0700, Michael Farmer wrote:
> >Dr Ted Bunch did the classification. I have to belive that=20
> he knows what he
> >it doing. The pieces are up on my website right now.
> >See them here
> >http://www.meteoriteguy.com/nwa2092.htm
> >http://www.meteoriteguy.com/nwa20922.htm
> >Price is $30.00 gram today only.
> >Mike Farmer
> >----- Original Message -----
> >From: "David Weir" <dgweir_at_earthlink.net>
> >To: "Adam Hupe" <adamhupe_at_comcast.net>
> >Cc: <bernd.pauli_at_paulinet.de>; <meteorite-list@meteoritecentral.com>
> >Sent: Thursday, March 25, 2004 4:11 PM
> >Subject: Re: [meteorite-list] LL7 Chondrites
> >
> >
> > > Hey Adam,
> > >
> > > Yes, I agree with you. Very perceptive. The two types are mutually
> > > exclusive based on the definition of Dodd. Type 7=20
> ordinary chondrites
> > > were originally defined by Dodd et al. (1975) according=20
> to specific
> > > petrographic characteristics. They listed three=20
> metamorphic criteria to
> > > distinguish between petrographic types 6 and 7:
> > >
> > > 1.the presence of poorly defined chondrules in type 6,=20
> but only relict
> > > chondrules in type 7
> > >
> > > 2.low-Ca pyroxenes in type 6 contain no more than 1.0 wt%=20
> CaO (1.0 wt% =3D
> > > ~1.9 mol% Wo), but more than 1.0 wt% in type 7;=20
> conversely, the CaO
> > > content of high-Ca pyroxenes decreases from type 6 to type 7
> > >
> > > 3.feldspar grains gradually coarsen to reach a size of at=20
> least 0.1 mm
> > > in type 7
> > >
> > > Perhaps this is one of those confused cases of=20
> classification in which
> > > different labs call things by different terminology.=20
> Could they have
> > > found both petrographic phases in the stone and used the slash to
> > > indicate this? Who did the classification?
> > >
> > > Regards,
> > > David
> > >
> > > ______________________________________________
> > > Meteorite-list mailing list
> > > Meteorite-list_at_meteoritecentral.com
> > > http://www.pairlist.net/mailman/listinfo/meteorite-list
> > >
> >
> >
> >
> >______________________________________________
> >Meteorite-list mailing list
> >Meteorite-list_at_meteoritecentral.com
> >http://www.pairlist.net/mailman/listinfo/meteorite-list
>=20
> Dr. Jeffrey N. Grossman phone: (703) 648-6184
> US Geological Survey fax: (703) 648-6383
> 954 National Center
> Reston, VA 20192, USA
>=20
>=20
>=20
> ______________________________________________
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>=20
Received on Fri 26 Mar 2004 07:53:46 AM PST