Re: [meteorite-list] Ablation Zone 5 Layers...Not
Hello Elton, All, I'm going to go through this bit by bit to do it justice... > Yes on a freshly recovered iron, there appears to be a "film" of what we > believe is "magnetite-like oxide/nitride micro-crystals, probably including > some sulfide and phosphide minerals" which form through interaction with hot > atmospheric plasma. Even though some of it is magnetic, some of it is easily > dislodged with a wipe of the finger. I assume this coating is relatable to the iridescent film which often coats stony meteorites - the film that often disappears within days of a fall. >I surmise that this rapidly goes to hematite or limonite but I've not thought >through the chemistry and I suspect a valence discrepancy that makes this type >meteoric "magnetite" unstable. The mineral assemblage in the coating/film is a >result of passage through the atmosphere and not per se the resulting changes >that occur with the passage of time on the surface. I shall point you toward this photograph of the external surface of a Sikhote-Alin. This iron was found ~50+ years after falling and still retained its exterior surface. The features you see are not made of melted Fe, but of an outer coating of iron oxide which formed during atmospheric descent. http://www.flickr.com/photos/cameteoritefinder/2335664239/sizes/l/ > I think I can proffer an argument for what is and is not a scientifically > underpinned definition of "crust" but I'll work on that later. For the time > being the use of "crust" by present definition involves glass and last time I > checked there is no such thing as "iron glass". Where did you get this definition? Why is it more valid than the one accepted by Buchwald, Nininger, Krinov, and the folks at the USNM? Why does fusion crust *have* to have glass in it? Honestly, this whole thing seems like a semantics battle on your part. >We expect to find something analogous to "crust" so we call what we see >"crust"-- I understand that. But when we stray too far everything including >dust mites, rust and, fungus gets called fusion crust. Right. Here: http://www.aerolite.org/catalogue/sikhote-alin-aaa-33-2.htm What you're looking at is the original external surface of the iron, made of that FeO layer that you keep insisting isn't fusion crust. It's perfectly analogous to the crust of stony meteorites, except, of course, in that it contains no glass. > As there is also a surface bluing occasionally observed (much like after > welding) this may be a directly formed oxide/nitride layer of chemically > altered meteorite while emerging from the incandescent phase of flight but > since I am unsure of the composition I'll leave it out of the below > discussion. I've seen that on stony meteorites as well. But since you're leaving it out, there's no real need to address it. > Chances are it is also quickly lost to weathering on the surface--even in the >museum drawer. Maybe. I saw some pretty Oum Dreyga's with such a film still present as of this winter - in a drawer in Alain Carion's shop in Paris. As such, I have the feeling that such layers may not simply sublimate with time, but they do seem to disappear rather rapidly when meteorites are left in the field. >The bottom line here is: we have to accept the probability of an ever-evolving >surface on our meteorites. Some happen quickly and may be gone in a flash and >some oh so slowly. This should not deter us however from discussing the basis >for each step that comes and goes. This also has nothing to do with our argument, for the most part. I don't think there's anyone here who denies such a fact, so stating it is somewhat superfluous. > I believe to discuss meteorite surface features e.g crust, non crust, flow > lines, ripples, regmaglypts, pits, bubbles, and all the variations, we should > come to a working definition in general principle of what to call them so we > know we are discussing the same thing. Sounds good to me. > Part of that is acceptance that there is an "ablation/ablated zone" generally > 2-6mm from the physical surface where the meteoroid last interacted with the > heat of reentry. This zone my eventually be proved a new type of "rind", > geologically speaking. Unfortunately, it's hard to gauge whether or not such a feature truly exists on stony meteorites because, due to their decreased conductivity, this heating does not occur over distances quite so large. See page two. http://adsabs.harvard.edu/full/1982Metic..17...27R So there's kind of an "ablationary rind," but it really only exists to the extent that you just noted in iron meteorites... > Of the layers physically present, I see two branches/variations which we may > reintegrate but for ease of discussion the first is mostly the non-silicate > bearing iron branch of "layers": So we *are* talking about irons' fusion crusts...ok... > The ablated/ablation zone includes amongst it layers: > 1)Lost Layer/ Null layer: The
Re: [meteorite-list] Ablation Zone 5 Layers...Not
Dear Jason If everything is a part of the fusion crust than every meteorite is fusion crusted end of discussion. So are you really saying that every meteorite regardless of how condition has fusion crust even if all the extra trans-located material is missing? I don't have the luxury of going point by point as you have but apparently you are unfamiliar with the Oxford and Cambridge dictionary definitions as well as all their Dictionaries of Geology. Most of the literature and practically all of the referenced websites use the silicate glassy/glassy term in defining fusion crust--and in context they are most always speaking of stoney meteorites. We've been down this discussion before and while I respect Buchwald's observations: he is an industrial metallurgist and had no training I can see in mineralogy nor geology. He became a iron meteorite subject matter expert in his own right( I don't know that he ever did any work on any other type. I see no incentive on his part to reevaluate the surface changes as he was focused on cataloging the interior features. Somehow I don't think "crust" was an issue for him and in the absence of inquiry into the use of the term there was never a need to rethink it. He has an email address--write him and ask him what he meant. Nininiger was a biology teacher and while another legitimate self-made expert in the field it wasn't technically oriented until late in his career. This shouldn't be taken as disrespectful and doesn't mean that everything he assumed was gospel-- especially given the state of scientific tools in his lifetime. He laid the foundation for meteoritical study but that doesn't mean he knew all there was to know about meteorites. His book about meteorite surface features was mainly a photo documentation with little analysis and generally lacking in comparative studies of the crust. Much of this argument that they are "the experts" and as such are infallible, is misguided and out of context, as the tools available now are vastly more quantitative than tools of their day. So is our body of knowledge more complete than during their careers. ( I am calling the ablation surface below any "crust" feature because well...it is. The ablation surface is the last level we can ascertain the fusion has occurred. When the crust is worn away the ablation surface is revealed. I am also not calling the oxide coating a "fusion crust" because,... well...it isn't ( necessarily) fused material and represents either condensation or contact metamorphism of the final flight air soaked, modified surface. I am also not calling the surface of SA's which show aero-thermo-dynamic interaction that form the troughs "crust" because partial melting/softening/gas jet ablation does not meet the definition of fusion/fusing. How you see it as fusion crust illustrates my point that we call everything fusion crust when it is not even fused material. I think it deserves a more objective review and understanding of the complexities and not reduced to a universal simplicity. As to my point about extensively rusted/shalely Canyon Diablos being said to have "fusion crust", sounds like we are in violent agreement. The point of addressing the loss of the coating over time was to suggest further inquiry into what the actual chemical composition was and to indicate I felt it was a class of mineral/compounds which were unstable in an oxygen rich atmosphere. Again --some irons have apparent classical fusion crust but, I have to disagree that all irons have fusion crust--that is why ablation surface is an important distinction and is better nomenclature that serves as a starting point for discussing all meteorite surfaces and where crust begins and ends. I believe when and where it is found it needs as much analytical scrutiny as we spend on the interior so we know its source material and how it came to be crust. Rather than me reiterate what I've already addressed perhaps you would like to read it more collaboratively as some of what you replied to skipped over where there is agreement and also you've challenged the studies about how deeply thermal alteration occurs in different meteorites. I am not ready to roll over on the claim that a chemically bonded oxide constitutes fusion crust unless you want to drop the word fusion. I proposed some terms for use in defining a meteorite's surface more descriptively. Other than disagree out of principle, you didn't give a counter argument as to why the model I laid out was in error. Finally I will reiterate the problems with trying to have a reasonable succinct discussion when out of context examples are introduced as if they were the rule rather than the exception they are. Elton --- On Fri, 11/20/09, Jason Utas wrote: > From: Jason Utas > Subject: Re: [meteorite-list] Ablation Zone 5 Layers...Not > To: "Meteorite-list" > Date: Friday, November 20, 2009, 6:58 AM > Hello Elton, All,
[meteorite-list] YD impact, again
Hi Darren - Thanks. We'll see "If the dates hold". The lead author in this is setting the impacts around 10,500 BCE, instead of 10,900 BCE. I really love it where the reporters summarize Firestone et al's "hypothesis" as an asteroid impact, instead of comet impact. E.P. Grondine Man and Impact in the Americas __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Fusion Crust on Irons--Not; Buchwald Diagram
- Original Message - From: "Phil Whitmer" To: Sent: Thursday, November 19, 2009 8:29 PM Subject: Fusion Crust on Irons--Not; Buchwald Diagram According to Buchwald: http://i190.photobucket.com/albums/z126/tboswell/b-1.jpg?t=1258679726 http://i190.photobucket.com/albums/z126/tboswell/c-1.jpg?t=1258679835 http://i190.photobucket.com/albums/z126/tboswell/a-1.jpg?t=125867 Interesting historical perspective. Phil Whitmer __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Fusion Crust on Irons--Not; Buchwald Diagram
- Original Message - From: "Phil Whitmer" To: Sent: Thursday, November 19, 2009 8:29 PM Subject: Fusion Crust on Irons--Not; Buchwald Diagram According to Buchwald: http://i190.photobucket.com/albums/z126/tboswell/b-1.jpg?t=1258679726 http://i190.photobucket.com/albums/z126/tboswell/c-1.jpg?t=1258679835 http://i190.photobucket.com/albums/z126/tboswell/a-1.jpg?t=125867 Interesting historical perspective. Phil Whitmer __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] New Hope for Plucky Japanese Asteroid Mission (Hayabusa)
http://www.spaceflightnow.com/news/n0911/19hayabusa/ New hope for plucky Japanese asteroid mission BY STEPHEN CLARK SPACEFLIGHT NOW November 19, 2009 Japanese engineers have devised a plan to combine parts from two partially-failed ion engines to resume the Hayabusa asteroid probe's journey back to Earth. In a press release Thursday, officials said they will use the neutralizer of Thruster A and the ion source of Thruster B to provide enough power to guide the 950-pound spacecraft home next June. Hayabusa launched in 2003 with four ion engines. Thruster A was shut down due to instability shortly after launch, while Thruster B was turned off after high voltage in its neutralization system. Thruster C was manually switched off after signs it might be damaged by high electrical currents, and Thruster D failed two weeks ago due to a voltage spike. The Nov. 4 glitch left Hayabusa without a propulsion system and put its scheduled return to Earth in serious doubt. But the new plan gives Japanese officials new hope. "While the operation still needs monitored carefully, the project team has concluded the spacecraft can maintain the current return cruise schedule back to the Earth around June of 2010, if the new engines configuration continues to work as planned," the Japan Aerospace Exploration Agency said in a statement. Hayabusa's four experimental microwave discharge ion engines consume xenon gas and expel the ionized propellant at high speeds to produce thrust. Ion engines are more efficient than conventional chemical thrusters because they use less fuel and can operate continuously for thousands of hours. The craft's thrusters have accumulated almost 40,000 hours of burn time since the probe launched. Plans call for the spacecraft to continue thrusting until March, when it will shut down the ion system and coast toward Earth for a parachuted landing in Australia. Hayabusa spent three months exploring asteroid Itokawa in late 2005. The probe took 1,600 pictures and collected about 120,000 pieces of near-infrared spectral data and 15,000 data points with its X-ray spectrometer to investigate the small potato-shaped asteroid's surface composition. The spacecraft approached Itokawa several times, attempting to fire a pellet into the asteroid's surface and retrieve rock samples through a funnel leading to a collection chamber. During a failed sampling attempt in November 2005, Hayabusa made an unplanned landing and spent up to a half-hour on Itokawa, becoming the first spacecraft to take off from an asteroid. Although telemetry showed Hayabusa likely did not fire its projectile while on the surface, scientists were hopeful bits of dust or pebbles found their way through the funnel and into the sample retrieval system. Hayabusa was later stymied by a fuel leak and ground controllers temporarily lost communications with the spacecraft, which is about the size of an average refrigerator. Controllers labored to overcome the issues, which were compounded by the loss of two orientation-controlling reaction wheels and power cells in an electrical battery. The craft's departure from Itokawa was delayed a year because of the problems, postponing its return to Earth from 2007 until 2010. __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Ablation Zone 5 Layers...Not
Hi Elton, You've brought up some very good discussion on the definition of fusion crusted specimens. I went to the authority, Buchwald's Iron Meteorites to see what he called it. He has written a lot about it. He states: "Cuts perpendicular to the surface of a freshly fallen iron meteorite disclose fusion crusts and heat affected rim zones. While the fusion crusts on stone meteorites are usually a product of simple melting, the crusts on iron meteorites are complex. The fusion crusts are the adhering remnants of ablated metal from the last part of the trajectory left on the surface when the velocity decreased below about 3 km/sec., and ablation ceased. The fusion crusts are, in principle, composed of an exterior fully oxidized, rapidly solidified nonmetallic melt." He shows a number of samples that are iron meteorites with various fusion crusts and identifies them that way. In some cases thick metallic fusion crust to describe flows and so forth. While I think there is some agreement with what Buchwald said and your trying to say, he still calls it fusion crust. Not to say that it is a term that is accurately describing a scientific effect on the outside of iron specimens. I have always felt and called some of my fresh iron falls fusion crusted because that is what Buchwald has defined them as in his books and feel it is a fair term to use unless a better term is identified and used by the scientific community that would label it different. I do know as you have pointed out that the term is often exaggerated way beyond the term that accurately defines it in Buchwald's Books and certainly abused by some seller of meteorites. Perhaps with this discussion, the overuse of the term on irons will be more carefully applied. All my best! --AL Mitterling Mitterling Meteorites - Original Message - From: "MEM" To: "Meteorite-list" ; "Jason Utas" Sent: Friday, November 20, 2009 9:01 AM Subject: Re: [meteorite-list] Ablation Zone 5 Layers...Not Dear Jason If everything is a part of the fusion crust than every meteorite is fusion crusted end of discussion. So are you really saying that every meteorite regardless of how condition has fusion crust even if all the extra trans-located material is missing? I don't have the luxury of going point by point as you have but apparently you are unfamiliar with the Oxford and Cambridge dictionary definitions as well as all their Dictionaries of Geology. Most of the literature and practically all of the referenced websites use the silicate glassy/glassy term in defining fusion crust--and in context they are most always speaking of stoney meteorites. We've been down this discussion before and while I respect Buchwald's observations: he is an industrial metallurgist and had no training I can see in mineralogy nor geology. He became a iron meteorite subject matter expert in his own right( I don't know that he ever did any work on any other type. I see no incentive on his part to reevaluate the surface changes as he was focused on cataloging the interior features. Somehow I don't think "crust" was an issue for him and in the absence of inquiry into the use of the term there was never a need to rethink it. He has an email address--write him and ask him what he meant. Nininiger was a biology teacher and while another legitimate self-made expert in the field it wasn't technically oriented until late in his career. This shouldn't be taken as disrespectful and doesn't mean that everything he assumed was gospel-- especially given the state of scientific tools in his lifetime. He laid the foundation for meteoritical study but that doesn't mean he knew all there was to know about meteorites. His book about meteorite surface features was mainly a photo documentation with little analysis and generally lacking in comparative studies of the crust. Much of this argument that they are "the experts" and as such are infallible, is misguided and out of context, as the tools available now are vastly more quantitative than tools of their day. So is our body of knowledge more complete than during their careers. ( I am calling the ablation surface below any "crust" feature because well...it is. The ablation surface is the last level we can ascertain the fusion has occurred. When the crust is worn away the ablation surface is revealed. I am also not calling the oxide coating a "fusion crust" because,... well...it isn't ( necessarily) fused material and represents either condensation or contact metamorphism of the final flight air soaked, modified surface. I am also not calling the surface of SA's which show aero-thermo-dynamic interaction that form the troughs "crust" because partial melting/softening/gas jet ablation does not meet the definition of fusion/fusing. How you see it as fusion crust illustrates my point that we call everything fusion crust when it is not even fused material. I think it deserves a more objective review and
Re: [meteorite-list] Ablation Zone 5 Layers...Not
Hi Elton, You've brought up some very good discussion on the definition of fusion crusted specimens. I went to the authority, Buchwald's Iron Meteorites to see what he called it. He has written a lot about it. He states: "Cuts perpendicular to the surface of a freshly fallen iron meteorite disclose fusion crusts and heat affected rim zones. While the fusion crusts on stone meteorites are usually a product of simple melting, the crusts on iron meteorites are complex. The fusion crusts are the adhering remnants of ablated metal from the last part of the trajectory left on the surface when the velocity decreased below about 3 km/sec., and ablation ceased. The fusion crusts are, in principle, composed of an exterior fully oxidized, rapidly solidified nonmetallic melt." He shows a number of samples that are iron meteorites with various fusion crusts and identifies them that way. In some cases thick metallic fusion crust to describe flows and so forth. While I think there is some agreement with what Buchwald said and your trying to say, he still calls it fusion crust. Not to say that it is a term that is accurately describing a scientific effect on the outside of iron specimens. I have always felt and called some of my fresh iron falls fusion crusted because that is what Buchwald has defined them as in his books and feel it is a fair term to use unless a better term is identified and used by the scientific community that would label it different. I do know as you have pointed out that the term is often exaggerated way beyond the term that accurately defines it in Buchwald's Books and certainly abused by some seller of meteorites. Perhaps with this discussion, the overuse of the term on irons will be more carefully applied. All my best! --AL Mitterling Mitterling Meteorites - Original Message - From: "MEM" To: "Meteorite-list" ; "Jason Utas" Sent: Friday, November 20, 2009 9:01 AM Subject: Re: [meteorite-list] Ablation Zone 5 Layers...Not Dear Jason If everything is a part of the fusion crust than every meteorite is fusion crusted end of discussion. So are you really saying that every meteorite regardless of how condition has fusion crust even if all the extra trans-located material is missing? I don't have the luxury of going point by point as you have but apparently you are unfamiliar with the Oxford and Cambridge dictionary definitions as well as all their Dictionaries of Geology. Most of the literature and practically all of the referenced websites use the silicate glassy/glassy term in defining fusion crust--and in context they are most always speaking of stoney meteorites. We've been down this discussion before and while I respect Buchwald's observations: he is an industrial metallurgist and had no training I can see in mineralogy nor geology. He became a iron meteorite subject matter expert in his own right( I don't know that he ever did any work on any other type. I see no incentive on his part to reevaluate the surface changes as he was focused on cataloging the interior features. Somehow I don't think "crust" was an issue for him and in the absence of inquiry into the use of the term there was never a need to rethink it. He has an email address--write him and ask him what he meant. Nininiger was a biology teacher and while another legitimate self-made expert in the field it wasn't technically oriented until late in his career. This shouldn't be taken as disrespectful and doesn't mean that everything he assumed was gospel-- especially given the state of scientific tools in his lifetime. He laid the foundation for meteoritical study but that doesn't mean he knew all there was to know about meteorites. His book about meteorite surface features was mainly a photo documentation with little analysis and generally lacking in comparative studies of the crust. Much of this argument that they are "the experts" and as such are infallible, is misguided and out of context, as the tools available now are vastly more quantitative than tools of their day. So is our body of knowledge more complete than during their careers. ( I am calling the ablation surface below any "crust" feature because well...it is. The ablation surface is the last level we can ascertain the fusion has occurred. When the crust is worn away the ablation surface is revealed. I am also not calling the oxide coating a "fusion crust" because,... well...it isn't ( necessarily) fused material and represents either condensation or contact metamorphism of the final flight air soaked, modified surface. I am also not calling the surface of SA's which show aero-thermo-dynamic interaction that form the troughs "crust" because partial melting/softening/gas jet ablation does not meet the definition of fusion/fusing. How you see it as fusion crust illustrates my point that we call everything fusion crust when it is not even fused material. I think it deserves a
Re: [meteorite-list] Ablation Zone 5 Layers...Not
List: I think this one looks cool. http://curator.jsc.nasa.gov/antmet/amn/AMNAug04/MIL03369.htm Greg S. > From: alm...@kconline.com > To: mstrema...@yahoo.com; meteorite-list@meteoritecentral.com; > meteorite...@gmail.com > Date: Fri, 20 Nov 2009 11:45:20 -0500 > Subject: Re: [meteorite-list] Ablation Zone 5 Layers...Not > > Hi Elton, > > You've brought up some very good discussion on the definition of fusion > crusted specimens. I went to the authority, Buchwald's Iron Meteorites to > see what he called it. He has written a lot about it. He states: "Cuts > perpendicular to the surface of a freshly fallen iron meteorite disclose > fusion crusts and heat affected rim zones. While the fusion crusts on stone > meteorites are usually a product of simple melting, the crusts on iron > meteorites are complex. The fusion crusts are the adhering remnants of > ablated metal from the last part of the trajectory left on the surface when > the velocity decreased below about 3 km/sec., and ablation ceased. The > fusion crusts are, in principle, composed of an exterior fully oxidized, > rapidly solidified nonmetallic melt." > > He shows a number of samples that are iron meteorites with various fusion > crusts and identifies them that way. In some cases thick metallic fusion > crust to describe flows and so forth. While I think there is some agreement > with what Buchwald said and your trying to say, he still calls it fusion > crust. Not to say that it is a term that is accurately describing a > scientific effect on the outside of iron specimens. > > I have always felt and called some of my fresh iron falls fusion crusted > because that is what Buchwald has defined them as in his books and feel it > is a fair term to use unless a better term is identified and used by the > scientific community that would label it different. I do know as you have > pointed out that the term is often exaggerated way beyond the term that > accurately defines it in Buchwald's Books and certainly abused by some > seller of meteorites. Perhaps with this discussion, the overuse of the term > on irons will be more carefully applied. All my best! > > --AL Mitterling > > Mitterling Meteorites > > > - Original Message - > From: "MEM" > To: "Meteorite-list" ; "Jason Utas" > > Sent: Friday, November 20, 2009 9:01 AM > Subject: Re: [meteorite-list] Ablation Zone 5 Layers...Not > > > Dear Jason If everything is a part of the fusion crust than every meteorite > is fusion crusted end of discussion. So are you really saying that every > meteorite regardless of how condition has fusion crust even if all the extra > trans-located material is missing? > > I don't have the luxury of going point by point as you have but apparently > you are unfamiliar with the Oxford and Cambridge dictionary definitions as > well as all their Dictionaries of Geology. Most of the literature and > practically all of the referenced websites use the silicate glassy/glassy > term in defining fusion crust--and in context they are most always speaking > of stoney meteorites. > > We've been down this discussion before and while I respect Buchwald's > observations: he is an industrial metallurgist and had no training I can > see in mineralogy nor geology. He became a iron meteorite subject matter > expert in his own right( I don't know that he ever did any work on any other > type. I see no incentive on his part to reevaluate the surface changes as he > was focused on cataloging the interior features. Somehow I don't think > "crust" was an issue for him and in the absence of inquiry into the use of > the term there was never a need to rethink it. He has an email > address--write him and ask him what he meant. > > Nininiger was a biology teacher and while another legitimate self-made > expert in the field it wasn't technically oriented until late in his career. > This shouldn't be taken as disrespectful and doesn't mean that everything he > assumed was gospel-- especially given the state of scientific tools in his > lifetime. He laid the foundation for meteoritical study but that doesn't > mean he knew all there was to know about meteorites. His book about > meteorite surface features was mainly a photo documentation with little > analysis and generally lacking in comparative studies of the crust. > > Much of this argument that they are "the experts" and as such are > infallible, is misguided and out of context, as the tools available now are > vastly more quantitative than tools of their day. So is our body of > knowledge more complete than during their careers. ( > > I am calling the ablation surface below any "crust" feature because > well...it is. The ablation surface is the last level we can ascertain the > fusion has occurred. When the crust is worn away the ablation surface is > revealed. I am also not calling the oxide coating a "fusion crust" > because,... well...it isn't ( necessarily) fused material and represents > eith
[meteorite-list] Utah Meteor....
Good Morning Listoids! I spent all of Thursday talking to the fine folks in Southwest Utah. The military folks at Dugway Proving Grounds were helpful in providing me with information about the Granite Peak area and at this time are not allowing any access. But took my name and number should that change. The area just South of Granite Peak between Callao and Fish Springs, along the grounds Southern border, is BLM and State. We can hope the impact was there. The Juab County Sheriff department said that area is essentially wide open but should use extreme caution if you dare enter there. Does anyone on the list know Christopher Cokinos well enough to call him and ask what information he may have. He was on the news and said he was researching the path and gathering statements. I like his new book "The Fallen Sky". I have never met him. Hope to! Dennis in NWNM _ Windows 7: I wanted simpler, now it's simpler. I'm a rock star. http://www.microsoft.com/Windows/windows-7/default.aspx?h=myidea?ocid=PID24727::T:WLMTAGL:ON:WL:en-US:WWL_WIN_myidea:112009 __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Utah Meteor....
Dennis and list... > Does anyone on the list know Christopher Cokinos well enough to call > him and ask what information he may have. I know Chris from dealings with him at Sky & Telescope. seems like a good guy who likes backyard observing. I'd try contacting him directly. clear skies, Kelly J. Kelly Beatty Senior Contributing Editor SKY & TELESCOPE 617-416-9991 SkyandTelescope.com __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Ablation Zone 5 Layers...Not
Al, Perhaps you should have read my last message a little more thoroughly as well. I went out of my way to clarify. I even said the following: "Not a single person on this list is saying that all iron meteorites have fusion crusts, just as not a single person on this list has ever said that all stony meteorites have fusion crusts. My point of view is that generally speaking, when an iron meteorite falls, it is covered by what is deemed a fusion crust (barring extenuating circumstances like an explosive impact [eg. Sikhote shrapnel], or extremely late atmospheric fragmentation). Just as most stony meteorite exhibit a fusion crust as well (barring an explosive impact [eg. Carancas], etc, etc)." I further stated that: "Well yeah. Rust isn't fusion crust, but I might as well ask you if you think that taking an acetylene torch to a stony meteorite and melting its surface would create a fusion crust. The key, I think you would agree, is in its method of formation" So, no, I don't believe that all iron meteorites are covered by fusion crust. Just the fresh ones, assuming they're not the product of an explosive impact, late fragmentation, etc. Do you disagree? Jason What Elton is suggesting is that On Fri, Nov 20, 2009 at 8:59 AM, al mitt wrote: > Hi Elton, > > You've brought up some very good discussion on the definition of fusion > crusted specimens. I went to the authority, Buchwald's Iron Meteorites to > see what he called it. He has written a lot about it. He states: "Cuts > perpendicular to the surface of a freshly fallen iron meteorite disclose > fusion crusts and heat affected rim zones. While the fusion crusts on stone > meteorites are usually a product of simple melting, the crusts on iron > meteorites are complex. The fusion crusts are the adhering remnants of > ablated metal from the last part of the trajectory left on the surface when > the velocity decreased below about 3 km/sec., and ablation ceased. The > fusion crusts are, in principle, composed of an exterior fully oxidized, > rapidly solidified nonmetallic melt." > > He shows a number of samples that are iron meteorites with various fusion > crusts and identifies them that way. In some cases thick metallic fusion > crust to describe flows and so forth. While I think there is some agreement > with what Buchwald said and your trying to say, he still calls it fusion > crust. Not to say that it is a term that is accurately describing a > scientific effect on the outside of iron specimens. > > I have always felt and called some of my fresh iron falls fusion crusted > because that is what Buchwald has defined them as in his books and feel it > is a fair term to use unless a better term is identified and used by the > scientific community that would label it different. I do know as you have > pointed out that the term is often exaggerated way beyond the term that > accurately defines it in Buchwald's Books and certainly abused by some > seller of meteorites. Perhaps with this discussion, the overuse of the term > on irons will be more carefully applied. All my best! > > --AL Mitterling > > Mitterling Meteorites > > - Original Message - From: "MEM" > To: "Meteorite-list" ; "Jason Utas" > > Sent: Friday, November 20, 2009 9:01 AM > Subject: Re: [meteorite-list] Ablation Zone 5 Layers...Not > > > Dear Jason If everything is a part of the fusion crust than every meteorite > is fusion crusted end of discussion. So are you really saying that every > meteorite regardless of how condition has fusion crust even if all the extra > trans-located material is missing? > > I don't have the luxury of going point by point as you have but apparently > you are unfamiliar with the Oxford and Cambridge dictionary definitions as > well as all their Dictionaries of Geology. Most of the literature and > practically all of the referenced websites use the silicate glassy/glassy > term in defining fusion crust--and in context they are most always speaking > of stoney meteorites. > > We've been down this discussion before and while I respect Buchwald's > observations: he is an industrial metallurgist and had no training I can > see in mineralogy nor geology. He became a iron meteorite subject matter > expert in his own right( I don't know that he ever did any work on any other > type. I see no incentive on his part to reevaluate the surface changes as he > was focused on cataloging the interior features. Somehow I don't think > "crust" was an issue for him and in the absence of inquiry into the use of > the term there was never a need to rethink it. He has an email > address--write him and ask him what he meant. > > Nininiger was a biology teacher and while another legitimate self-made > expert in the field it wasn't technically oriented until late in his career. > This shouldn't be taken as disrespectful and doesn't mean that everything he > assumed was gospel-- especially given the state of scientific tools in his > lifetime. He laid the found
[meteorite-list] The Northwest Fireball, 11/17
Is anyone up in Wyoming-Idaho-Washington searching for fallout from the big bolide? Has anyone heard if anything has been recovered, or a likely search area? Best! Tracy Latimer _ Hotmail: Trusted email with powerful SPAM protection. http://clk.atdmt.com/GBL/go/177141665/direct/01/ __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Utah Meteor...
http://www.ksl.com/?nid=148&sid=8736952&autostart=y Here is Chris on the morning news in Salt Lake City. Thanks Kelly, I'll try the University for his home phone is unlisted. Dennis _ Hotmail: Trusted email with Microsoft's powerful SPAM protection. http://clk.atdmt.com/GBL/go/177141664/direct/01/ http://clk.atdmt.com/GBL/go/177141664/direct/01/ __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Item About Meteorites in Ripleys-Believe-it-or-not
List: I'm on a fact finding mission, is this true? It makes sense to me, but the funny thing is I've only found a few that small. Maybe I need to get my eyes checked... again. http://news.yahoo.com/comics/ripleys-believe-it-or-not Greg S. _ Windows 7: I wanted simpler, now it's simpler. I'm a rock star. http://www.microsoft.com/Windows/windows-7/default.aspx?h=myidea?ocid=PID24727::T:WLMTAGL:ON:WL:en-US:WWL_WIN_myidea:112009 __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Item About Meteorites in Ripley s-Believe-it-or-not - undate
List: I misread it - I though it was meteorites reaching the ground. But it's meteors hitting the atmosphere. Greg S. _ Bing brings you maps, menus, and reviews organized in one place. http://www.bing.com/search?q=restaurants&form=MFESRP&publ=WLHMTAG&crea=TEXT_MFESRP_Local_MapsMenu_Resturants_1x1 __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Mars Odyssey THEMIS Images: November 16-20, 2009
MARS ODYSSEY THEMIS IMAGES November 16-20, 2009 o Kaiser Crater Dunes (16 November 2009) http://themis.asu.edu/zoom-20091116a o Mangala Vallis (17 November 2009) http://themis.asu.edu/zoom-20091117a o Coprates Chasma (18 November 2009) http://themis.asu.edu/zoom-20091118a o Tyrrhena Fossae (19 November 2009) http://themis.asu.edu/zoom-20091119a o Tyrrhena Fossae (20 November 2009) http://themis.asu.edu/zoom-20091120a All of the THEMIS images are archived here: http://themis.asu.edu/latest.html NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in co.oration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena. __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Mars Exploration Rovers Update: November 13-19, 2009
http://marsrovers.jpl.nasa.gov/mission/status.html SPIRIT UPDATE: Extrication Attempt Begins - sols 2084-2090, Nov. 13-19, 2009: Spirit has begun her long-awaited extrication process. The first commanded motion was on Sol 2088 (Nov. 17, 2009). Two straight forward steps of 2.5 meters (8.2 feet) each were sequenced. However, due to a hair-trigger limit on the rover tilt, the drive stopped as soon as it began and no discernable motion in the rover was observed. With improved value for the rover tilt, the same two-step motion was sequenced on Sol 2090 (Nov. 19, 2009). Spirit successfully completed the first step of the planned motion. The second step was not performed because Spirit exceeded the 1-centimeter (0.4-inch) three-dimensional distance limit that was imposed in the plan. The center of the rover moved approximately 12 millimeters (0.5 inch) forward, 7 millimeters (0.3 inch) to the left and about 4 millimeters (0.2 inch) down. The rover tilt changed by around 0.1 degree. Small forward motion was observed with the non-operable right-front wheel. The left-front wheel showed indications of climbing. It is cautioned that these motions are too small to establish any trends at this time. The plan ahead is to continue forward driving once all the necessary analysis is complete and reviewed. As of Sol 2090 (Nov. 19, 2009), Spirit's solar-array energy production is 346 watt-hours, with an atmospheric opacity (tau) of 0.517 and a dust factor of 0.588. Total odometry is 7,729.97 meters (4.80 miles). OPPORTUNITY UPDATE: 'Marquette' Study Begins - sols 2063-2068, Nov. 12-17, 2009: Opportunity has been investigating a rock called "Marquette Island." The rover approached the rock on Sol 2063 (Nov. 12, 2009) and has been using the Moessbauer (MB) spectrometer and alpha particle X-ray spectrometer (APXS) to collect measurements on the rock to assist in determining the rock composition. Opportunity also has taken close-up images using the microscopic imager (MI) on Sol 2065 (Nov. 14, 2009). The rock abrasion tool (RAT) on the arm will lightly brush the rock to reveal the surface beneath the layer of dust. After receiving the results of the RAT brush, the science team will decide whether to look even deeper into the rock by grinding a couple of millimeters (about a tenth of an inch) down into it and performing additional science observations. There has also been extensive imaging of the surrounding rocks around Marquette. The elevation mirror shroud of the miniature thermal emission spectrometer (Mini-TES) is being opened when appropriate with the expectation of eventual dust cleaning. No dust cleaning of the Mini-TES mirror has been noted yet. As of Sol 2068 (Nov. 17, 2009), Opportunity's solar-array energy production was 385 watt-hours, with an atmospheric opacity (tau) of 0.482 and a dust factor of 0.530. Total odometry was 18,906.82 meters (11.75 miles). __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] AD - Meteorites for sale! Lasers too! 10% off
Hi to all! I have some nice meteorites listed on ebay at some very nice prices. 10% off any sale done off ebay (less fees for me, better price for you) http://search.ebay.com/_W0QQsassZwanderingstarmeteoritesQQhtZ-1 There is Tatahouine, Lunar, Martian, Camel Donga, Olivine Diogenite and a good deal more - Included a few complete slices of a very neat NWA meteorite with interesting features (testing is currently being done) and some nice L/LL(?) end cuts. Check out my website, those interested in Astronomy might have interest in new lasers pointers I have for sale (great for pointing things out in the sky to others) The lasers are $5 off the listed price until thanksgiving. Thanks for looking, Greg C. www.wanderingstarmeteorites.com IMCA 4682 __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Ablation Zone 5 Layers...Not
Elton, All, > Dear Jason If everything is a part of the fusion crust than every meteorite > is fusion crusted end of discussion. So are you really saying that every > meteorite regardless of how condition has fusion crust even if all the extra > trans-located material is missing? It appears that you simply did not read my previous message. If you had, you would have seen the following statement: "I would define the fusion crust as the layer of meteoric material transformed into melt during a meteorite's ablative stages of flight, which later solidifies into a solid coating of material on the surface of the stone, iron, what have you." To be frank, I'm disappointed in your response. I take a bit of time in responding to you. As something of a courtesy, you might afford me the same. At least going so far as to read the entirety of what I've written would be a nice start. > I don't have the luxury of going point by point as you have If you're going to reply to a mere part of my message, I would be much obliged if you would refrain from attempting to summarize everything I've said with false statements such as those above. I mean, it's still kind of dickish if you're going to perpetuate the thread without addressing someone who disagrees with you in full, but the least you could do is refrain from lying when possible. >but apparently you are unfamiliar with the Oxford and Cambridge dictionary >definitions as well as all their Dictionaries of Geology. Most of the >literature and practically all of the referenced websites use the silicate >glassy/glassy term in defining fusion crust--and in context they are most >always speaking of stoney meteorites. Well, there are two obvious problems with your reasoning here. 1) You're trusting the authors of a bunch of geologic dictionaries with the definition of a meteoric concept. Have you ever looked through encyclopedias of geology and glanced at the definitions of, say, meteorites, or of related concepts? They're very often lacking, or incorrect about any number of details regarding meteoritics. It's not their fault - it's just that meteorites are a fringe-science related to geology. Related to the studies of, but generally not studied by mainstream geologists. And then you quote Norton's book. Norton graduated with a degree of Astronomy, and while he did great petrographic work, he has about as much qualification in determining what is or isn't a fusion crust as does anyone else with a similar degree who's been recreationally studying meteorites for any period of time. Granted, he has written a number of great books describing meteorites, but you're talking about a specialized aspect of the science in which he has done little to no research. 2) You're insinuating that these authors have stated that iron meteorites do not form fusion crusts when, in all likelihood, they probably just 'left out the part about irons.' It's one thing to say that 'meteorites have a glassy fusion crust' when ~92% of all meteorites are stony and thus have glassy fusion crusts. It's another thing entirely to say that iron meteorites don't form fusion crusts. If writing a general encyclopedic definition of a fusion crust, do you think an author is going to delve that deeply into each definition? I would think it a great thing if he or she did, but I know for a fact that that's not how such books are written. No one could know that much about every field of EPS, and if they took the time to research each subject to that level of depth, the book would be obsolete by decades before it was halfway done. > We've been down this discussion before and while I respect Buchwald's > observations: he is an industrial metallurgist and had no training I can see > in mineralogy nor geology. Well, you clearly do not respect his observations because you yourself are refuting them. Well, perhaps respect is a bit of a vague word in this case. You may "respect" them, but you certainly don't agree with them. Nigh on every meteorite mentioned in his handbook is either noted as possessing a fusion crust - or is noted as lacking one (the implication being that the given iron would have had a fusion crust were it a more recent fall). So you clearly are at odds with him on this issue. >He became a iron meteorite subject matter expert in his own right( I don't >know that he ever did any work on any other type. I see no incentive on his >part to reevaluate the surface changes as he was focused on cataloging the >interior features. Yes and no. His goal was to write a comprehensive historical, physical, and chemical description of every meteorite. The only irons for which he did not provide a general description of the exterior (and its relative degree of age, insofar as it could be inferred from the state of the iron's fusion crust, general morphology, and reheated rim) were the irons of which he was unable to obtain a representative sample, and of which no older description
[meteorite-list] Rocks from Space Picture of the Day - November 21, 2009
http://www.rocksfromspace.org/November_21_2009.html __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Rocks from Space Picture of the Day - November 21, 2009
A truly beautiful stone! Thanks for sharing. Cheers, Jeff - Original Message - From: "Michael Johnson" To: Sent: Saturday, November 21, 2009 2:53 PM Subject: [meteorite-list] Rocks from Space Picture of the Day - November 21,2009 http://www.rocksfromspace.org/November_21_2009.html __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Tooele, Meteorite found? Dugway increases security
Dear List, Dugway Proving Grounds has increased security since the Utah meteor. Fox 13, Salt Lake is reporting that a man has found a "black and polished rock" while "looking for arrowheads". http://lunarmeteoritehunters.blogspot.com/2009/11/utah-meteorite-news-dugway-increases.html Best Regards,. Dirk Ross...Tokyo __ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
