[meteorite-list] Diogenite Nomenclature
Dear List Members and fellow diogenite enthusiasts, I talked with Tony Irving this morning regarding the use of 'Olivine Diogenite' in classifications and abstracts. I have been enlightened to the ever evolving diogenite classification scheme. Seems a new 'pigeon hole' has been created due to new meteorites which are comprised of mostly olivine, the Dunite meteorites. Find below Tony's reply and link to an abstract that discusses their proposed, and more accurate separation of the Diogenite meteorites. Best Regards, Greg Hupe Begin forwarded message: Hi Greg: Here is a link to the abstract for our presentation in London last year. Most people seem to like this proposed scheme http://www.lpi.usra.edu/meetings/metsoc2011/pdf/5223.pdf ... [NWA 1877, NWA 5480 and other similar meteorites] would now be harzburgitic diogenites, but olivine diogenite is still OK as a general term. The nature of nomenclature is that it evolves with the need to encompass new specimens, and we have mostly NWA and private collectors to thank for that. Cheers, Tony __ 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] Diogenite Nomenclature
Hi, the problem of the taxonomy of diogenites has been discussed recently in this paper: Andrew W. BECK and Harry Y. McSWEEN Jr (2010),Diogenites as polymict breccias composed of orthopyroxenite and harzburgite, Meteoritics Planetary Science, Volume 45, Issue 5, May 2010, Pages: 850872, DOI: 10./j.1945-5100.2010.01061.x The authors have proposed an adaptation of the classical classification of terrestrial ultramafic rocks. I agree with their suggestions. Depending of the proportion of olivine, harzburgitic diogenites and dunitic diogenites can be defined. The difficulty of the classification of diogenites is the size of the samples used by classifiers. These lithologies are often extremely heterogeneous, and it is often not possible to determine accurately the proportion of olivine using a single polished section. Anyway, the problem of taxonomy is not a critical scientific issue. Of course, it is important to determine the abundance of olivine in a diogenite, but this proportion does not change the interpretation we have on these rocks. At present, all the diogenites which have been investigated in depth, are cumulate rocks, certainly coming from a number of intrusions. These intrusions contain certainly different types of rocks, including regular diogenites and olivine bearing diogenites. For example, trace elements indicate that NWA5480 and Tatahouine come probably from the same intrusion... Not from the mantle of the parent body. Cheers Jean-Alix Selon Greg Hupe gmh...@centurylink.net: Dear List Members and fellow diogenite enthusiasts, I talked with Tony Irving this morning regarding the use of 'Olivine Diogenite' in classifications and abstracts. I have been enlightened to the ever evolving diogenite classification scheme. Seems a new 'pigeon hole' has been created due to new meteorites which are comprised of mostly olivine, the Dunite meteorites. Find below Tony's reply and link to an abstract that discusses their proposed, and more accurate separation of the Diogenite meteorites. Best Regards, Greg Hupe Begin forwarded message: Hi Greg: Here is a link to the abstract for our presentation in London last year. Most people seem to like this proposed scheme http://www.lpi.usra.edu/meetings/metsoc2011/pdf/5223.pdf ... [NWA 1877, NWA 5480 and other similar meteorites] would now be harzburgitic diogenites, but olivine diogenite is still OK as a general term. The nature of nomenclature is that it evolves with the need to encompass new specimens, and we have mostly NWA and private collectors to thank for that. Cheers, Tony __ 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 __ 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] Diogenite Nomenclature
Hi Diogenite Fans, Any time we have a discussion about diogenites, I look forward to Doug Dawn's input. Calling Mr. Dawn, calling Mr. Dawn. :) From a layman's standpoint, the difference between olivine diogenites and regular diogenites is easy to see in a hand specimen. The texture of an olivine diogenite is quite different than what we see in classic diogenites like Tatahouine and Johnstown. One look at NWA 5480, NWA 1877, or any other OD, and it's easy to see that there must be a compositional difference between these OD's and other diogenites. I have some unclassified samples which reportedly came from the same finder and strewnfield as NWA 5480. They are too small to have classified on their merit, but even in pieces that are only 1 or 2 grams, their unique texture and character is evident. To my eyes (and microscope), these unclassified pieces are obviously from the olivine diogenite family. Can I prove it with lab data? No. But they are fun to look at. :) At any rate, from a collector's standpoint, I think OD's should be distinguished from the regular diogenites. Anyone who has owned or handled a sizeable chunk of OD (with that delicious fusion crust that is rarely seen), knows it is something special deserving of it's own classification. Best regards, MikeG -- - Web - http://www.galactic-stone.com Facebook - http://www.facebook.com/galacticstone Twitter - http://twitter.com/GalacticStone Pinterest - http://pinterest.com/galacticstone RSS - http://www.galactic-stone.com/rss/126516 - On 9/15/12, bar...@univ-brest.fr bar...@univ-brest.fr wrote: Hi, the problem of the taxonomy of diogenites has been discussed recently in this paper: Andrew W. BECK and Harry Y. McSWEEN Jr (2010),Diogenites as polymict breccias composed of orthopyroxenite and harzburgite, Meteoritics Planetary Science, Volume 45, Issue 5, May 2010, Pages: 850–872, DOI: 10./j.1945-5100.2010.01061.x The authors have proposed an adaptation of the classical classification of terrestrial ultramafic rocks. I agree with their suggestions. Depending of the proportion of olivine, harzburgitic diogenites and dunitic diogenites can be defined. The difficulty of the classification of diogenites is the size of the samples used by classifiers. These lithologies are often extremely heterogeneous, and it is often not possible to determine accurately the proportion of olivine using a single polished section. Anyway, the problem of taxonomy is not a critical scientific issue. Of course, it is important to determine the abundance of olivine in a diogenite, but this proportion does not change the interpretation we have on these rocks. At present, all the diogenites which have been investigated in depth, are cumulate rocks, certainly coming from a number of intrusions. These intrusions contain certainly different types of rocks, including regular diogenites and olivine bearing diogenites. For example, trace elements indicate that NWA5480 and Tatahouine come probably from the same intrusion... Not from the mantle of the parent body. Cheers Jean-Alix Selon Greg Hupe gmh...@centurylink.net: Dear List Members and fellow diogenite enthusiasts, I talked with Tony Irving this morning regarding the use of 'Olivine Diogenite' in classifications and abstracts. I have been enlightened to the ever evolving diogenite classification scheme. Seems a new 'pigeon hole' has been created due to new meteorites which are comprised of mostly olivine, the Dunite meteorites. Find below Tony's reply and link to an abstract that discusses their proposed, and more accurate separation of the Diogenite meteorites. Best Regards, Greg Hupe Begin forwarded message: Hi Greg: Here is a link to the abstract for our presentation in London last year. Most people seem to like this proposed scheme http://www.lpi.usra.edu/meetings/metsoc2011/pdf/5223.pdf ... [NWA 1877, NWA 5480 and other similar meteorites] would now be harzburgitic diogenites, but olivine diogenite is still OK as a general term. The nature of nomenclature is that it evolves with the need to encompass new specimens, and we have mostly NWA and private collectors to thank for that. Cheers, Tony __ 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 __ 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 __ Visit the Archives at
Re: [meteorite-list] Diogenite Nomenclature
Hi Mike, No. The Olivine diogenites do not display systematically a texture different to that of regular diogenites. Tatahouine is not a correct example because it is unbrecciated and have very large crystals. The largest I have seen is 5 cm in length! Tatahouine is unique. NWA 5480 is exceptional too, but of course different to Tatahouine. If you compare two brecciated diogenites, one with olivine, the other devoid (or nearly devoid) of olivine, (e.g., Roda with Johnstown), you cannot tell with the hand specimens which one is the olivine diogenite. You need polished sections. You are certainly able to distinguish NWA 1877, from NWA 5480, Bilanga and Tatahouine. They are different rocks with particular aspect. It is not so simple with all the diogenites! Cheers Jean-Alix Selon Galactic Stone Ironworks meteoritem...@gmail.com: Hi Diogenite Fans, Any time we have a discussion about diogenites, I look forward to Doug Dawn's input. Calling Mr. Dawn, calling Mr. Dawn. :) From a layman's standpoint, the difference between olivine diogenites and regular diogenites is easy to see in a hand specimen. The texture of an olivine diogenite is quite different than what we see in classic diogenites like Tatahouine and Johnstown. One look at NWA 5480, NWA 1877, or any other OD, and it's easy to see that there must be a compositional difference between these OD's and other diogenites. I have some unclassified samples which reportedly came from the same finder and strewnfield as NWA 5480. They are too small to have classified on their merit, but even in pieces that are only 1 or 2 grams, their unique texture and character is evident. To my eyes (and microscope), these unclassified pieces are obviously from the olivine diogenite family. Can I prove it with lab data? No. But they are fun to look at. :) At any rate, from a collector's standpoint, I think OD's should be distinguished from the regular diogenites. Anyone who has owned or handled a sizeable chunk of OD (with that delicious fusion crust that is rarely seen), knows it is something special deserving of it's own classification. Best regards, MikeG -- - Web - http://www.galactic-stone.com Facebook - http://www.facebook.com/galacticstone Twitter - http://twitter.com/GalacticStone Pinterest - http://pinterest.com/galacticstone RSS - http://www.galactic-stone.com/rss/126516 - On 9/15/12, bar...@univ-brest.fr bar...@univ-brest.fr wrote: Hi, the problem of the taxonomy of diogenites has been discussed recently in this paper: Andrew W. BECK and Harry Y. McSWEEN Jr (2010),Diogenites as polymict breccias composed of orthopyroxenite and harzburgite, Meteoritics Planetary Science, Volume 45, Issue 5, May 2010, Pages: 850872, DOI: 10./j.1945-5100.2010.01061.x The authors have proposed an adaptation of the classical classification of terrestrial ultramafic rocks. I agree with their suggestions. Depending of the proportion of olivine, harzburgitic diogenites and dunitic diogenites can be defined. The difficulty of the classification of diogenites is the size of the samples used by classifiers. These lithologies are often extremely heterogeneous, and it is often not possible to determine accurately the proportion of olivine using a single polished section. Anyway, the problem of taxonomy is not a critical scientific issue. Of course, it is important to determine the abundance of olivine in a diogenite, but this proportion does not change the interpretation we have on these rocks. At present, all the diogenites which have been investigated in depth, are cumulate rocks, certainly coming from a number of intrusions. These intrusions contain certainly different types of rocks, including regular diogenites and olivine bearing diogenites. For example, trace elements indicate that NWA5480 and Tatahouine come probably from the same intrusion... Not from the mantle of the parent body. Cheers Jean-Alix Selon Greg Hupe gmh...@centurylink.net: Dear List Members and fellow diogenite enthusiasts, I talked with Tony Irving this morning regarding the use of 'Olivine Diogenite' in classifications and abstracts. I have been enlightened to the ever evolving diogenite classification scheme. Seems a new 'pigeon hole' has been created due to new meteorites which are comprised of mostly olivine, the Dunite meteorites. Find below Tony's reply and link to an abstract that discusses their proposed, and more accurate separation of the Diogenite meteorites. Best Regards, Greg Hupe Begin forwarded message: Hi Greg: Here is a link to the abstract for our presentation in London last year. Most people seem to like this proposed scheme
