Re: [meteorite-list] metachondrite
All: I wondering if at some time as more of these meta or'7-s' are found, there could be classification system implemented like there currently is for the 3-type. There is 3.0 through 3.9 based on further analysis; how about a 6.1 through 6.9, were the higher number represent more metamorphism, and other unique changes in the re-crystallization. Just a thought. Greg S. > Date: Sun, 24 Oct 2010 17:56:03 -0400 > From: jgross...@usgs.gov > CC: meteorite-list@meteoritecentral.com > Subject: Re: [meteorite-list] metachondrite > > I don't think it's appropriate to say that somebody who does not like a > term suggested in a couple of abstracts is a "purist who sh[ies] away > from any thinking out of the conventional box"! As far as I understand > the term, there do not seem to be any concepts behind "metachondrite" > that are outside the boxes of the existing terminology. It just appears > to me to be a new word for something we already have terms to describe. > So it comes down to a question of semantics. > > "Type 7" chondrites have not been "excommunicated" either. It has been a > problematic term because some of the rocks that led to the coining of > this term turned out to be impact melt rocks, which is a different > phenomenon from the thermal metamorphism we are trying to describe with > petrologic types. Once you take these out, there are a few rocks that > arguably are metamorphosed to slightly higher temperatures than normal > type 6 chondrites, with the primary indicator of this being high CaO > content of pyroxene. I have no strong objection to these being called > type 7, although I'm not convinced that the term is particularly > necessary. Still, if we're sure we're not dealing with impact melted > rocks or rocks that have experienced partial melting, then I think the > term is ok. That's why some of these got through the nomcom. Once again, > this is not an "outside the box" term, just a minor extension of the > usual classification scheme (when used carefully). > > And finally, as I said before, the word "primitive" in PAC refers to the > composition, which is close to chondritic compared to, say, that of a > eucrite, aubrite, or angrite. The same word is frequently used by > geologists to describe the Earth's mantle before it gets depleted in > certain elements by generation of melts. The word is perfectly fine in > this context. > > Jeff > > > On 2010-10-24 4:20 PM, Ted Bunch wrote: > > Jeff and the LIST members: > > > > Yes, Van Schmus and Wood (V & W) did a classic study over 40 years > > ago, they worked with the available classic OC meteorites and made a > > workable classification scheme. That was 43 years ago and things > > change, especially the 10s of thousands of non-classic meteorites > > available for study and advanced instrumentation including the now > > common usage of SEM BSE imagery and elemental distribution mapping. V > > & W probably never saw a completely recrystallized OC, they are not > > even common now. > > > > Investigators started seeing OCs that had absolutely NO relict > > chondrules or chondrule fragments. So, apparently, the V & W scheme > > became inadequate over time and the "petrologic" classification scheme > > was unofficially amended with L7, LL7, H7, etc. Seemed reasonable to > > us. But, not to the purists who shy away from any thinking out of the > > conventional box. "Sevens" were excommunicated, a few got through a > > couple of NOM COMs. Because "sevens" are completely recrystallized > > with some elemental loss, we thought that metachondrite was > > appropriate, but not until our paper on metachondrites goes through > > the peer review process - if you are clever handicappers, don't bet on > > this horse. I think we have the same chance as did Joan of Arc with > > her Inquisition. > > > > Metamorphism of chondrites took place over hundreds of thousands of > > years at elevated temperatures and not necessarily under closed > > systems. With this concept in mind -- > > > > What is a "primitive achondrite"? Actually, they are > > metamorphosed/recrystallized rocks that are not the same, even > > compositionally, as their parent rocks. Primitive? I think not. One > > dictionary definition of primitive is “not derived from other things”. > > Acapulcoites and lodranites _are derived from other things, hence not > > primitive. > > > > _A primitive meteorite to me means a CI or may be a CM1, although even > > these t
Re: [meteorite-list] metachondrite
f the >> target rock and heat. The other one is after the formation of such a >> celestial body, the radioactive decay of its instable and heavy elements. >> The larger such a body is, the more of that stuff it has, the hotter it can >> get - up to the complete melting of the body. And the larger such an body is >> the longer it can keep the heat - Earth e.g. is large enough, that it was >> quite still warm down there, where the Chilean miners were sitting. >> >> Impacts, you know what happens, if the smack is hefty, then the rock beneath >> simply melts - making these IMB, impact melt breccias meteorites, >> usually quite black, homogenous and with textureless glasses.. >> The metachondrites are different from them. >> If you take that idea with that heating by decay, then you can suppose, that >> they once sat more deeper, closer to the core of their parent body than the >> 3ers, 4ers,... where it got hotter and where it was longer hot. >> >> Now, cause 6 was obviously not the end, Dodd in the 1970ies thought it is >> necessary to have also a 7. >> >> Problem: Most of these crazy stones have no chondrules left. >> Therefore some say: A chondrite is called a chondrite because it has >> chondrules! >> A stone, that has no chondrules has to be called: achondrite!! >> >> Therfore a 7er-chondrite would be per definition not allowed. >> And because the stuff is directly derived from chondrites, which are the >> most primitive matter we have, >> we put these stones into the group, we already have, where the ACAPs, LODs, >> WINs are already sitting in >> and call them "primitive achondrites". >> >> And that is somewhat unhappy. >> Achondrites we have all that stuff from differentiated, non-chondritic >> parent bodies, >> like the Vesta matters eucrites, diogenites, howardites, but also the >> aubrites, ureilites, brachinites, angrites, Martians, Lunars... >> >> But from these stones, we know exactly from their composition that they were >> chondrites. >> And "primitive" doesn't fit so well neither - because they aren't that >> primitive but among the chondrites the most metamorph, most evolved, most >> equilibrated ones of all. >> And they are not an unchanged primary meteorite, they are a product of them. >> The opposite of "primitive". >> >> The term "Metachondrite" is there more exact, it says: Look I was a >> chondrite - I am a metamorph chondrite. >> So in the name the genesis of the rock is already visible. >> And it allows to be more specific, >> as one hasn't to lump all these rocks, from ACAPs, WINs and all these >> diverse "ex-chondrites" together under a PAC label although they are so >> heterogeneous and stemming from so many different parent bodies. >> But they easily can be finer specified, in attaching their individual >> prefix: L-metachondrite, H-metachondrite, CV-metachondrite ect. >> And everyone knows immediately, what the stone is about. Not so if you have >> only a "PAC" standing there. >> >> >> H, supersimply one could say, metachondrites are chondrites which were >> longer in the oven. >> >> >> We hope that was relatively correct? >> If not, please experts, correct us! >> >> >> Aaaand because we were so nice, to try to explain that, >> and because Eric and Steve could be now hungry for such a whack and >> extremely rare representative of such a meteorite, >> we shall be allowed, >> to note shortly, that from NWA 6438 prov. >> we still have left the >> >> 5.868g-slice >> http://www.chladnis-heirs.com/nwa6348-5.868g.JPG >> >> and the 6.655g corner-cut. >> http://www.chladnis-heirs.com/nwa6348-6.655g-part-encut.JPG >> >> Both from the cleaner not so stained part, nicely fresher. >> >> And that the main mass of that first L-meta is now free again, >> Accepting offers: >> http://www.chladnis-heirs.com/nwa6348-48.119g-end-cut.JPG >> >> >> Btw. David has added NWA 6348 already to his systematics and wrote an >> article about. >> http://www.meteoritestudies.com/ >> >> (Click in the side menu on "Metachondrites"). >> >> Best! >> Martin& Stefan >> >> >> PS: Eric wrote: >> "My understanding is a chondrite with multiple lithologies." >> >> That would be regolith breccias or polymict breccias, >> where different fragments of rocks were mixed together and solified by >> various impacts o
Re: [meteorite-list] metachondrite
Hello Jeff, we tried this time more to explain, what these stones are and not so the terminology, because to some list-members it seemed unclear, what these metachondrites/PACs/7ers are and how they formed. How they shall be called, we leave to each one individually (cause it doesn't change the stones). But Jeff note, that at least the term chondrite vs. achondrite shouldn't be too dogmatically handled, if you remember, that there is also a class formally reckoned among the chondrites, although it hasn't any chondrules, the CI-chondrites - which, if one would be in that sense consequent, would then belong nominally also in the PAC-pot, wouldn't they? For us at least, the metachondrite-terminology would have some advantages. If we read L-metachondrite, LL-metchondrite, CR-metachondrite, we simply know, what the stone IS. An L-metachondrite - everybody knows immediately, aha, precursor material was an L-chondrite, that stone belongs into the L-group. With "PAC"? PAC can be everything. And if we open a pot labeled "PAC" - then we lump together meteorites from many different parent bodies. That would be unique in the nomenclature and inconsistent. Because no class/denomination there, under which you have meteorites from different parent bodies. Traditionally you have in a group only stones from more or the less of one kind, from one parent body, and they were named according the first find/fall described. Aubrites from Aubres, Acapulcoites from Acapulco, Brachinites from Brachina, Shergottites from Shergotty...and so on (and we were lucky, that none of the namesake was from Poland, Święcanites, ostrzeszówites... ) - or which were historically named like the eucrites, diogenites, howardites, or where the relations were understood, then at least with the initial from the 1st find/fall. CI from Ivuna, CV from Vigarano, CK from Karoonda ect. With that metamorph chondrites it doesn't work. Simply because they are not a class of their own, they clearly belong into the existing groups. To the Hs, to the Ls, to the CVs ect. (so "ungrouped" they are in no case). If you would call them "7", then we wouldn't haven't a problem. And of course, one could also pack everything, which has a relic chondrule left, to the 6ers. But to throw all those, which haven't, into the unspecific PAC - creating almost a pseudo-class or -group, would mean an unnecessary coarsening. Also we don't know then the hierarchic structure of the terminology of the classification scheme so well. Would we have then these main groups with these hypernyms:Chondrites, Achondrites (from differentiated parent bodies), Irons, Primitive Achondrites? If so, or also in general, wouldn't it be then anyway necessary to preserve the L-metachondrites, H-metachondrites, LL-meta... as subgroups of the PACs, because we have so heterogeneous meteorites in that group then? Or could one then create rather something like a L-PAC, H-PAC, CV-PAC - (huh ACAPPAC sounds cool). Hmmm, would be much more elegant, to put the PACs (as long as we don't know so much about the precursors of the ACAP/LODs and the WINs) simply as subgroup to the achondrites and the Meta7PACs, there where they generically and chemically belong to, to the individual chondrite classes as metachondrites. If that's feasible at all. Thoughts only, Martin & Stefan -Ursprüngliche Nachricht- Von: meteorite-list-boun...@meteoritecentral.com [mailto:meteorite-list-boun...@meteoritecentral.com] Im Auftrag von Jeff Grossman Gesendet: Sonntag, 24. Oktober 2010 17:45 An: meteorite-list@meteoritecentral.com Betreff: Re: [meteorite-list] metachondrite Here is the opposing view: The definition of type 6 chondrites comes from one of the classic papers in meteoritics, Van Schmus and Wood (1967): "As mentioned above, type 6 contains the most recrystallized chondrites. These chondrites show extensive-to-complete obliteration of the primary textures (Fig. 11), extensive evidence of recrystallization of the original olivine and pyroxene crystals, and good-to-excellent development of plagioclase..." Note that this definition includes chondrites that are so recrystallized that chondrules are no longer recognizable. A number of us petrologists think that most "type 7" chondrites fit comfortably within this definition of type 6, and consider the former term to be superfluous. With continued heating, chondrites eventually begin to partially melt (reaching the Fe-FeS eutectic temperature and eventually the point where a feldspathic silicate liquid can form). At this point, differentiation can begin, as these liquids separate from residual solids. When some differentiation occurs, it can produce rocks that are nearly chondritic in composition, but depleted in elements that went into these liquids. That is the definition of "primitive achondrite
Re: [meteorite-list] metachondrite
e.g. is large enough, that it was quite still warm down there, where the Chilean miners were sitting. Impacts, you know what happens, if the smack is hefty, then the rock beneath simply melts - making these IMB, impact melt breccias meteorites, usually quite black, homogenous and with textureless glasses.. The metachondrites are different from them. If you take that idea with that heating by decay, then you can suppose, that they once sat more deeper, closer to the core of their parent body than the 3ers, 4ers,... where it got hotter and where it was longer hot. Now, cause 6 was obviously not the end, Dodd in the 1970ies thought it is necessary to have also a 7. Problem: Most of these crazy stones have no chondrules left. Therefore some say: A chondrite is called a chondrite because it has chondrules! A stone, that has no chondrules has to be called: achondrite!! Therfore a 7er-chondrite would be per definition not allowed. And because the stuff is directly derived from chondrites, which are the most primitive matter we have, we put these stones into the group, we already have, where the ACAPs, LODs, WINs are already sitting in and call them "primitive achondrites". And that is somewhat unhappy. Achondrites we have all that stuff from differentiated, non-chondritic parent bodies, like the Vesta matters eucrites, diogenites, howardites, but also the aubrites, ureilites, brachinites, angrites, Martians, Lunars... But from these stones, we know exactly from their composition that they were chondrites. And "primitive" doesn't fit so well neither - because they aren't that primitive but among the chondrites the most metamorph, most evolved, most equilibrated ones of all. And they are not an unchanged primary meteorite, they are a product of them. The opposite of "primitive". The term "Metachondrite" is there more exact, it says: Look I was a chondrite - I am a metamorph chondrite. So in the name the genesis of the rock is already visible. And it allows to be more specific, as one hasn't to lump all these rocks, from ACAPs, WINs and all these diverse "ex-chondrites" together under a PAC label although they are so heterogeneous and stemming from so many different parent bodies. But they easily can be finer specified, in attaching their individual prefix: L-metachondrite, H-metachondrite, CV-metachondrite ect. And everyone knows immediately, what the stone is about. Not so if you have only a "PAC" standing there. H, supersimply one could say, metachondrites are chondrites which were longer in the oven. We hope that was relatively correct? If not, please experts, correct us! Aaaand because we were so nice, to try to explain that, and because Eric and Steve could be now hungry for such a whack and extremely rare representative of such a meteorite, we shall be allowed, to note shortly, that from NWA 6438 prov. we still have left the 5.868g-slice http://www.chladnis-heirs.com/nwa6348-5.868g.JPG and the 6.655g corner-cut. http://www.chladnis-heirs.com/nwa6348-6.655g-part-encut.JPG Both from the cleaner not so stained part, nicely fresher. And that the main mass of that first L-meta is now free again, Accepting offers: http://www.chladnis-heirs.com/nwa6348-48.119g-end-cut.JPG Btw. David has added NWA 6348 already to his systematics and wrote an article about. http://www.meteoritestudies.com/ (Click in the side menu on "Metachondrites"). Best! Martin& Stefan PS: Eric wrote: "My understanding is a chondrite with multiple lithologies." That would be regolith breccias or polymict breccias, where different fragments of rocks were mixed together and solified by various impacts on the surface of an asteroid. -Ursprüngliche Nachricht- Von: meteorite-list-boun...@meteoritecentral.com [mailto:meteorite-list-boun...@meteoritecentral.com] Im Auftrag von Steve Dunklee Gesendet: Freitag, 22. Oktober 2010 18:09 An: jgross...@usgs.gov; meteorite-list@meteoritecentral.com Betreff: Re: [meteorite-list] metachondrite So by what I have read metachondrites are material that was once chondrite based on tfL what this suggests is you can take condrite material and have it accrete on a large parent body and make meta chondrite. I think it would be material that formed closer to the sun cooling quickly on one side giving it chondritic attributes and o isotopes closer to the tfL. Cheers Steve Dunklee __ 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 -- Dr. Jeffrey N. Grossman phone: (703) 648-6184 US Geological Survey fax: (703) 648-6383 954 National Center Reston, VA 20192, USA __ 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] metachondrite
one hasn't to lump all these rocks, from ACAPs, WINs and all these diverse "ex-chondrites" together under a PAC label although they are so heterogeneous and stemming from so many different parent bodies. But they easily can be finer specified, in attaching their individual prefix: L-metachondrite, H-metachondrite, CV-metachondrite ect. And everyone knows immediately, what the stone is about. Not so if you have only a "PAC" standing there. H, supersimply one could say, metachondrites are chondrites which were longer in the oven. We hope that was relatively correct? If not, please experts, correct us! Aaaand because we were so nice, to try to explain that, and because Eric and Steve could be now hungry for such a whack and extremely rare representative of such a meteorite, we shall be allowed, to note shortly, that from NWA 6438 prov. we still have left the 5.868g-slice http://www.chladnis-heirs.com/nwa6348-5.868g.JPG and the 6.655g corner-cut. http://www.chladnis-heirs.com/nwa6348-6.655g-part-encut.JPG Both from the cleaner not so stained part, nicely fresher. And that the main mass of that first L-meta is now free again, Accepting offers: http://www.chladnis-heirs.com/nwa6348-48.119g-end-cut.JPG Btw. David has added NWA 6348 already to his systematics and wrote an article about. http://www.meteoritestudies.com/ (Click in the side menu on "Metachondrites"). Best! Martin & Stefan PS: Eric wrote: "My understanding is a chondrite with multiple lithologies." That would be regolith breccias or polymict breccias, where different fragments of rocks were mixed together and solified by various impacts on the surface of an asteroid. -Ursprüngliche Nachricht- Von: meteorite-list-boun...@meteoritecentral.com [mailto:meteorite-list-boun...@meteoritecentral.com] Im Auftrag von Steve Dunklee Gesendet: Freitag, 22. Oktober 2010 18:09 An: jgross...@usgs.gov; meteorite-list@meteoritecentral.com Betreff: Re: [meteorite-list] metachondrite So by what I have read metachondrites are material that was once chondrite based on tfL what this suggests is you can take condrite material and have it accrete on a large parent body and make meta chondrite. I think it would be material that formed closer to the sun cooling quickly on one side giving it chondritic attributes and o isotopes closer to the tfL. Cheers Steve Dunklee __ 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] metachondrite
So by what I have read metachondrites are material that was once chondrite based on tfL what this suggests is you can take condrite material and have it accrete on a large parent body and make meta chondrite. I think it would be material that formed closer to the sun cooling quickly on one side giving it chondritic attributes and o isotopes closer to the tfL. Cheers Steve Dunklee On Thu Oct 21st, 2010 9:02 AM EDT Jeff Grossman wrote: > This is a term coined by Ted Bunch and Tony Irving, but to my >knowledge there is no peer-reviewed publication defining the term. >You'll find the definition in an AGU and a MetSoc abstract: > >http://www.lpi.usra.edu/meetings/metsoc2005/pdf/5218.pdf >http://adsabs.harvard.edu/abs/2006AGUFM.P51E1246B > >The term is not in widespread use and has not been used in the >Meteoritical Bulletin. Time will tell if it catches on. > >Jeff > >On 10/20/2010 11:36 PM, Steve Dunklee wrote: >> What is a metachondrite? Cheers Steve Dunklee >> >> >> >> __ >> 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 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] metachondrite
I cant get the abstract to run on my phone so I am still not sure what is meant by metachondrite. Could it be material that cooled too quickly to form chondrules but still retains many of the characteristics undifferentiated chondrules have? I have some pac and acap that have in some places partial spheres which would indicate rapid cooling on at least one side. When you consider the sun side may be realy hot and the shadow side almost absolute zero it kind of makes sence some material would instantly freeze on one side and remain melted on the other. Making a kind of half chondrule. With jagged edges on one side and smooth partial spheer on the other. Cheers Steve Dunklee __ 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] metachondrite
Well, of course it won't, (like the PACs are in principle neither a group...) but chemically and from the isotopes, those 7-PAC-Metas-Howevers are evolved chondrites of the respective chondrite groups. Chondrites with no chondrules anymore. But if I hear "achondrite", I'm thinking to HEDs and meteorites derived from differentiated stuff. Hence they are neither "ungrouped", we can group them definitely to the Ls, to the Hs, ect. And primitive achondrites, well those 7-Meta-PAC-Howevers - they are the most metamorph, most elquilibrated (former) chondrites, hence quite the opposite of "primitive". Traditionally, in my drawer labeled "PAC", there are sitting already the LOD/ACAP/WIN-boys inside. And they tussle always with those Ls, Hs, LLs, CVs, which just baked a little longer in their parent bodies, than the 4ers,5ers,6ers. (Uh and horribile dictu, in these LODs, ACAPs, WINs - called PACs, there are sometime chondrules and relict chondrules found!). Quietude into that drawer I could bring, if I put them all inside and would write "metachondrite" on the label, but always remembering, that each of them is cut from the cloth of his own group. (Or to say it else, they are rather ex-chondrites for me, than a-chondrites :-) Or to say it else again, for me it's more precise, to call the L-meta, H-meta, LL-meta ect... than to lump them all together in the bucket labeled PAC). But Jeff, you're naturally right - that is all only for my private domestic use. And I need simplifications, as the simple mind I am. As told, we are only laymen. We're the delivery boys of the very stones - the more weird, the better - though the papers about, the scientists have to write. Apropos "weird" - Weir D. gives as always good information about that complex: http://www.meteoritestudies.com/ Best! Martin -Ursprüngliche Nachricht- Von: meteorite-list-boun...@meteoritecentral.com [mailto:meteorite-list-boun...@meteoritecentral.com] Im Auftrag von Jeff Grossman Gesendet: Donnerstag, 21. Oktober 2010 19:39 An: meteorite-list@meteoritecentral.com Betreff: Re: [meteorite-list] metachondrite Even if the term "metachondrite" comes into use, it will not be the name of a meteorite group. It is semantically similar to the terms chondrite and achondrite, which are descriptive of the overall texture of a rock. Each of these terms encompasses objects from many parent bodies. And please don't think that the term "primitive achondrite" is incoherent. It is a very well-defined term, with an abundant scientific literature behind it. In fact, Irving et al. (metsoc abstract) suggest that metachondrite is essentially a synonym for PAC! Nor is the term "ungrouped" incoherent. This is a very precise term, meaning that the meteorite does not belong to an accepted group. If one adopts the term metachondrite, expect there to be metachondrite-ung classifications appearing. Jeff __ 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] metachondrite
Even if the term "metachondrite" comes into use, it will not be the name of a meteorite group. It is semantically similar to the terms chondrite and achondrite, which are descriptive of the overall texture of a rock. Each of these terms encompasses objects from many parent bodies. And please don't think that the term "primitive achondrite" is incoherent. It is a very well-defined term, with an abundant scientific literature behind it. In fact, Irving et al. (metsoc abstract) suggest that metachondrite is essentially a synonym for PAC! Nor is the term "ungrouped" incoherent. This is a very precise term, meaning that the meteorite does not belong to an accepted group. If one adopts the term metachondrite, expect there to be metachondrite-ung classifications appearing. Jeff On 10/21/2010 9:57 AM, Martin Altmann wrote: Hi, Time will tell if it catches on. I suppose it will, because to list these stones as Achondrite-ungr or Achondrite-prim. is very unspecific (and as far as I can rate it as a sheer layman, also sometimes somewhat misleading), while the metachondrite concept is very coherent. Of course it can take some time. (If you remember e.g. that the Bulletin still has with the lunaites only the very coarse discrimination in LUN-A and LUN-B, as we would still be in the time, where there were only the 2 DaGs and NWA 032.) Btw. these new results and that interesting topic about the additional 7ers/chondritic PACs/Metachondrites came on the table or was incited, as far as I can see, only and solely by means of newly found stones from the hot deserts. Hence another perfect example, why all, also in the MetSoc, should take care for keeping the deserts open. It helps a lot! Best! Martin -Ursprüngliche Nachricht- Von: meteorite-list-boun...@meteoritecentral.com [mailto:meteorite-list-boun...@meteoritecentral.com] Im Auftrag von Jeff Grossman Gesendet: Donnerstag, 21. Oktober 2010 15:02 An: meteorite-list@meteoritecentral.com Betreff: Re: [meteorite-list] metachondrite This is a term coined by Ted Bunch and Tony Irving, but to my knowledge there is no peer-reviewed publication defining the term. You'll find the definition in an AGU and a MetSoc abstract: http://www.lpi.usra.edu/meetings/metsoc2005/pdf/5218.pdf http://adsabs.harvard.edu/abs/2006AGUFM.P51E1246B The term is not in widespread use and has not been used in the Meteoritical Bulletin. Time will tell if it catches on. Jeff __ 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] metachondrite
Hi, >Time will tell if it catches on. I suppose it will, because to list these stones as Achondrite-ungr or Achondrite-prim. is very unspecific (and as far as I can rate it as a sheer layman, also sometimes somewhat misleading), while the metachondrite concept is very coherent. Of course it can take some time. (If you remember e.g. that the Bulletin still has with the lunaites only the very coarse discrimination in LUN-A and LUN-B, as we would still be in the time, where there were only the 2 DaGs and NWA 032.) Btw. these new results and that interesting topic about the additional 7ers/chondritic PACs/Metachondrites came on the table or was incited, as far as I can see, only and solely by means of newly found stones from the hot deserts. Hence another perfect example, why all, also in the MetSoc, should take care for keeping the deserts open. It helps a lot! Best! Martin -Ursprüngliche Nachricht- Von: meteorite-list-boun...@meteoritecentral.com [mailto:meteorite-list-boun...@meteoritecentral.com] Im Auftrag von Jeff Grossman Gesendet: Donnerstag, 21. Oktober 2010 15:02 An: meteorite-list@meteoritecentral.com Betreff: Re: [meteorite-list] metachondrite This is a term coined by Ted Bunch and Tony Irving, but to my knowledge there is no peer-reviewed publication defining the term. You'll find the definition in an AGU and a MetSoc abstract: http://www.lpi.usra.edu/meetings/metsoc2005/pdf/5218.pdf http://adsabs.harvard.edu/abs/2006AGUFM.P51E1246B The term is not in widespread use and has not been used in the Meteoritical Bulletin. Time will tell if it catches on. Jeff __ 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] metachondrite
This is a term coined by Ted Bunch and Tony Irving, but to my knowledge there is no peer-reviewed publication defining the term. You'll find the definition in an AGU and a MetSoc abstract: http://www.lpi.usra.edu/meetings/metsoc2005/pdf/5218.pdf http://adsabs.harvard.edu/abs/2006AGUFM.P51E1246B The term is not in widespread use and has not been used in the Meteoritical Bulletin. Time will tell if it catches on. Jeff On 10/20/2010 11:36 PM, Steve Dunklee wrote: What is a metachondrite? Cheers Steve Dunklee __ 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] Metachondrite(s)
Thank you Bernd, Yes a metachondrite is a meta(morphic) chondrite, nothing to do with lithologies. A good example of a CR Meta-chondrite is of course Tafassasset. Goodnight. Anne M. Black _www.IMPACTIKA.com_ (http://www.IMPACTIKA.com) _impact...@aol.com_ (mailto:impact...@aol.com) President of IMCA _www.IMCA.cc_ (http://www.IMCA.cc) In a message dated 10/21/2010 12:36:46 AM Mountain Daylight Time, bernd.pa...@paulinet.de writes: Good morning Steve, Greg and List, Greg S. wrote: "I understand a metachondrite to be a chondrite that has undergone metamorphism resulting in recrystalization. The composition is much the same as in the original chondrite. There are different affinities, such as 'H' 'L' or 'LL'. I think there are others including E's and 'C' chondrites." That's right. One further, important aspect is that they are all virtually without (relic) chondrules, devoid of chondrules with a few minor exceptions. See here: http://www4.nau.edu/meteorite/Meteorite/Metachondrites.html#En Best morning wishes, Bernd Anne M. Black http://www.impactika.com/ impact...@aol.com Vice-President, I.M.C.A. Inc. http://www.imca.cc/ __ 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
[meteorite-list] Metachondrite(s)
Good morning Steve, Greg and List, Greg S. wrote: "I understand a metachondrite to be a chondrite that has undergone metamorphism resulting in recrystalization. The composition is much the same as in the original chondrite. There are different affinities, such as 'H' 'L' or 'LL'. I think there are others including E's and 'C' chondrites." That's right. One further, important aspect is that they are all virtually without (relic) chondrules, devoid of chondrules with a few minor exceptions. See here: http://www4.nau.edu/meteorite/Meteorite/Metachondrites.html#En Best morning wishes, Bernd __ 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] metachondrite
I understand a metachondrite to be a chondrite that has undergone metamorphism resulting in recrystalization. The composition is much the same as in the original chondrite. There are different affinities, such as 'H' 'L' or 'LL'. I think there are others including E's and 'C' chondrites. I think they are a very interesting group of meteorites. Greg S. Sent from my iPhone On Oct 20, 2010, at 8:36 PM, Steve Dunklee wrote: > What is a metachondrite? Cheers Steve Dunklee > > > > __ > 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] metachondrite
My understanding is a chondrite with multiple lithologies. Eric On 10/20/2010 8:36 PM, Steve Dunklee wrote: What is a metachondrite? Cheers Steve Dunklee __ 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] metachondrite
What is a metachondrite? Cheers Steve Dunklee __ 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
[meteorite-list] Metachondrite ?
http://www.lpi.usra.edu/meetings/metsoc2005/pdf/5218.pdf ah...I have see a news, my NWA 1058 its a metachondrite. Matteo --- Jeff Kuyken <[EMAIL PROTECTED]> ha scritto: > Hi Martin, > > I can certainly see what you are saying but that was > not really my point. My > point is that it is not up to us to 'make-up' > classifications without the > proper science being done. Admittedly, I've only > seen a few photos of the > Caopt Rey pieces and in my opinion the one that was > just posted by Cartsen > is certainly a highly shocked piece but it's not an > IMB. I think if you > compare them to meteorites like Cat Mountain or Mike > Farmer's NWA 2085 you > will see what I mean. That said, it is certainly a > gorgeous meteorite which > I wouldn't mind having a piece myself! ;-) > > Cheers, > > Jeff > > > - Original Message - > From: Martin Altmann > To: Jeff Kuyken ; > meteorite-list@meteoritecentral.com > Sent: Friday, September 23, 2005 8:18 PM > Subject: Re: [meteorite-list] Capot Rey...photos > please of the H5 > > > Hi Jeff, > > as far as I understand the term "IMB" does not name > a completely and > uniformly molten rock. > Else, I would have have problems to understand the > "B", if there aren't any > fragments of the precessor material to be found in > the melt (and I think, we > easily will sled into the PAC corner). > Different classification of the same find as IMB or > H5 f.i. are easily > explainable. Take for instance Dho 010, there you > have broad streams of melt > flowing around chondritic fragments in different > stages of melting, some > even unaltered, therefore one can determinate the > type (have to look Dho 010 > if I remember right is H6). > And furthermore take our good old Gao! There you > have stones, which are > simply more or less normal chondrites, other stones > show large melt pockets > and again others are more or less totally molten and > have to be regarded, if > one doesn't know about the other average Gao > specimens, with no doubt as > IMBs. Take a look on David Weir's page, there you > have such an example. > Thus with Gao we have the whole spectra - H5, H5 > with melt, IMB. > It's always the same, it depends what for a stone > the classificators get, > what for sections they do have. > Remember the NWA 1109, they caught parts with > slightly below 10% Dio, thus > it's an EUC-P, another cut, another stone from the > same find with >10%, > voila they had to call it a How. > Take also good old Zag. There exist pieces with only > a single lithology, if > those would have been handed in for typing, Zag > wouldn't have bin classified > as regolith breccia. Take the NWA-Rumurutis, some > are nice brecciae, > result - obviously paired ones (lalalaa I know, I'm > not a scientist, but if > it's looking the same in every detail and the stuff > is so rare) got > different classifications. Some R4s are paired with > R3-6... > Ooops, all I'm writing here, is about the optical, > physical appearance of > the stones, not chemically. > > Now, I would guess, with Capot Rey, they took either > a piece without melt > (if exists) or determinated the type from a not > molten fragment in the melt. > > But look at the phantastic pieces of Carsten, those > dark fat rivers of melt > around the grey round jigsaw pieces. Hence if Dho > 010, who looks the same, > but is only much more weathered, was called a IMB, I > dare to say in my > Lieschen-Mueller-opinion > (Lieschen Mueller is the German sister of John Doe), > Capot Rey is an IMB > too. > > Of course again we would need a concretion of terms > from a qualified mouth. > With type-7 vs. PAC vs. IMB we learned, that it has > to do with the isotopes > and in general nobody is sure about the criteria, > now we have IMB vs. MR (melt rock) vs H or L with > IMB vs H or L with visible > huge parts of melt, but not assigned, > or we have to resign ourself to being more types of > rock out there in space > as we have terms for them :-) > > Buckleboo! > Martin > > > - Original Message - > From: "Jeff Kuyken" <[EMAIL PROTECTED]> > To: "drtanuki" <[EMAIL PROTECTED]>; > > Sent: Friday, September 23, 2005 10:57 AM > Subject: Re: [meteorite-list] Capot Rey...photos > please of the H5 > > > > I would be a bit cautious about calling something > an IMB unless it has > been > > formally classified as such. My understanding is > that this meteorite was > > classified as H5 but after further cutting later > was found to be highly > > shocked. Let's not forget that IMB is basically a > scientific term > referring > > to the fact that the pressure reached about 75-90 > GPa and is rated as S6+. > > It's original shock rating was only S2. A new > piece should probably be > > submitted for re-classification so a proper > determination can be made. > > > > Cheers, > > > > Jeff > > > > - Original Message - > > From: drtanuki > > To: meteorite-list@meteoritecentral.com > > Sent: Friday, September 23, 2005 9:47 AM > > Subject: [m
RE: [meteorite-list] Metachondrite ?
a metachonderite is what was formerly known as an achoderite but was from a chonderitic parent body and possibly conatined remaining chondrules From: Pelé Pierre-Marie <[EMAIL PROTECTED]> To: MeteoriteList Subject: [meteorite-list] Metachondrite ? Date: Thu, 22 Sep 2005 21:37:48 +0200 (CEST) Hello to the List Members, I visited today the NAU Website and discovered in the classification the term of "metachondrite" : http://www4.nau.edu/meteorite/ (for example for NWA 1839 : metachondrite (CV affinity) Can you tell me what it is ? Thanks a lot Pierre-Marie PELE www.meteor-center.com ___ Appel audio GRATUIT partout dans le monde avec le nouveau Yahoo! Messenger Téléchargez cette version sur http://fr.messenger.yahoo.com __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
RE: [meteorite-list] Metachondrite ?
Here might be an explanation. http://www.lpi.usra.edu/meetings/metsoc2005/pdf/5218.pdf Moni From: Pelé Pierre-Marie <[EMAIL PROTECTED]> To: MeteoriteList Subject: [meteorite-list] Metachondrite ? Date: Thu, 22 Sep 2005 21:37:48 +0200 (CEST) Hello to the List Members, I visited today the NAU Website and discovered in the classification the term of "metachondrite" : http://www4.nau.edu/meteorite/ (for example for NWA 1839 : metachondrite (CV affinity) Can you tell me what it is ? Thanks a lot Pierre-Marie PELE www.meteor-center.com ___ Appel audio GRATUIT partout dans le monde avec le nouveau Yahoo! Messenger Téléchargez cette version sur http://fr.messenger.yahoo.com __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Metachondrite ?
Hello to the List Members, I visited today the NAU Website and discovered in the classification the term of "metachondrite" : http://www4.nau.edu/meteorite/ (for example for NWA 1839 : metachondrite (CV affinity) Can you tell me what it is ? Thanks a lot Pierre-Marie PELE www.meteor-center.com ___ Appel audio GRATUIT partout dans le monde avec le nouveau Yahoo! Messenger Téléchargez cette version sur http://fr.messenger.yahoo.com __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
RE: [meteorite-list] Metachondrite
I've never Metachondrite I didn't like, poikilitically speaking that is. (a thousand pardons ;-) Bob Original Message: - From: [EMAIL PROTECTED] Date: 29 Jul 2005 16:11:44 UT To: Meteorite-list@meteoritecentral.com Subject: [meteorite-list] Metachondrite Tom inquired: > what in the heck is a metachondrite? Ingo responded: > ... in geology "Meta-" stands for metamorphosis ... Hi Tom, Ingo, and List, I think what Tom saw was a compound word: met + achondrite => meteorite - achondrite Best regards, Bernd __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list mail2web - Check your email from the web at http://mail2web.com/ . __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Metachondrite
Tom inquired: > what in the heck is a metachondrite? Ingo responded: > ... in geology "Meta-" stands for metamorphosis ... Hi Tom, Ingo, and List, I think what Tom saw was a compound word: met + achondrite => meteorite - achondrite Best regards, Bernd __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
