Dr. Rubin, If I read your response carefully, I believe you are saying that the petrologic state should not depend on the type of metamorphic process which makes sense. Seems to me that the the isotopic analysis should be used to identify chondritic material from achondritic material.
Mendy Ouzillou ----- Original Message ----- > From: Richard Montgomery <[email protected]> > To: Alan Rubin <[email protected]>; Peter Scherff <[email protected]>; > 'Adam' <[email protected]> > Cc: > Sent: Monday, March 4, 2013 5:14 PM > Subject: Re: [meteorite-list] Type 7 chondrites > > What thoughts about Taffessasset in this regard? Anyone wish to chime in? > Richard M > > > ----- Original Message ----- From: "Alan Rubin" > <[email protected]> > To: "Peter Scherff" <[email protected]>; > "'Adam'" <[email protected]> > Sent: Monday, March 04, 2013 3:41 PM > Subject: Re: [meteorite-list] Type 7 chondrites > > >> Most classifiers don't use the type-7 designation because many of the > chondrites that have been called type-7 seem to be impact-melt breccias. Most > researchers believe that thermal metamorphism probably caused by asteroidal > heating engendered by the decvay of short-lived radionuclides like 26-Al > heated > chondrites from type 3 to 4 to 5 to 6. If shock was responsible for causing > a > rock to be called type 7, then it seemed more prudent to just call it shocked > and not use the type-7 designation. Most researchers believe that the > primitive > achondrites were also partly (or completely) melted by heating caused by the > decay of 26-Al. I am not of these camps; it seems to me that heating of > chondrites from type 3 to type 6 also results from impact heating and that > the > primitive achondrites formed in an analogous way, but that is another story. >> Alan >> >> >> Alan Rubin >> Institute of Geophysics and Planetary Physics >> University of California >> 3845 Slichter Hall >> 603 Charles Young Dr. E >> Los Angeles, CA 90095-1567 >> phone: 310-825-3202 >> e-mail: [email protected] >> website: http://cosmochemists.igpp.ucla.edu/Rubin.html >> >> >> ----- Original Message ----- From: "Peter Scherff" > <[email protected]> >> To: "'Adam'" <[email protected]> >> Sent: Monday, March 04, 2013 3:14 PM >> Subject: [meteorite-list] Type 7 chondrites >> >> >>> >>> Hi, >>> >>> Is there any consensus about petrologic type 7 chondrites? Are they > better >>> classified as Primitive Achondrites? If type 7 is different from > primitive >>> achondtites what is the line between them? >>> >>> Thanks, >>> >>> Peter Scherff >>> >>> ______________________________________________ >>> >>> Visit the Archives at http://www.meteorite-list-archives.com >>> Meteorite-list mailing list >>> [email protected] >>> http://six.pairlist.net/mailman/listinfo/meteorite-list >> >> ______________________________________________ >> >> Visit the Archives at http://www.meteorite-list-archives.com >> Meteorite-list mailing list >> [email protected] >> http://six.pairlist.net/mailman/listinfo/meteorite-list >> > > ______________________________________________ > > Visit the Archives at http://www.meteorite-list-archives.com > Meteorite-list mailing list > [email protected] > http://six.pairlist.net/mailman/listinfo/meteorite-list > ______________________________________________ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list [email protected] http://six.pairlist.net/mailman/listinfo/meteorite-list
