Re: [meteorite-list] Fusion crusts on stony meteorites
I would say it is likely an impact melt and not a fusion crust. It is not uncommon for impact melts to have unaltered clasts of the original material in them and well as small vugs formed from gasses in the melt. Nice photos John. -- Eric Olson 7682 Firethorn Dr Fayetteville, NC 28311 http://www.star-bits.com Kashuba [EMAIL PROTECTED] wrote: = Michael, Darren, Jim and list, I agree with Jim on this. My slice of the same stone has fragments set in a clearly bubbly melt. I suggest that this accumulated on the back side of the stone during oriented flight. Check out my pictures: http://www.johnkashuba.com/Pages/Meteorite%20Pages/Pictures/NWA2826LL5.htm Regards, - John John Kashuba Ontario, California -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Thursday, March 22, 2007 9:16 PM To: [EMAIL PROTECTED] Cc: Meteorite-list@meteoritecentral.com Subject: Re: [meteorite-list] Fusion crusts on stony meteorites Hi Mike and Darren, I probably would have had that response too without the benefit of turning these over in my hands and looking at them in 3 dimensions. I'm 99% sure that if you held these in your hands, and especially if you looked at them under the microscope, you would conclude the black areas are crust. This scan of reverse side of the 28 gram slide may be more convincing: http://img.photobucket.com/albums/v614/CaneySprings/NWA2826LL528gmMarcinCima lareversecl.jpg I also made an oblique photo of the other slice which shows the contiguity of the area with the fragments(lower right hand corner of the top photo, lower hand corner left of the lower photo) with the rest of the crust. http://img.photobucket.com/albums/v614/CaneySprings/NWA282648gmobliqueview-1 .jpg http://img.photobucket.com/albums/v614/CaneySprings/NWA282648gmobliqueviewre verse-1.jpg However, I'm sure I have about a thousandth the expertise of either of you so I could well be off base. Best wishes, Jim I agree, I dont think that it is fusion crust, more likely a brecciated section on the edge of the meteorite. Michael Farmer --- Darren Garrison [EMAIL PROTECTED] wrote: On Thu, 22 Mar 2007 21:58:51 -0400 (EDT), you wrote: Hello Berndt et al., I thought you and the list members might find interesting a phenomenon that was shown to me by Marcin Cimala. In cutting an LL5 he found areas where thick crust had built up and actually incorporated within the crust small angular fragments of relatively unaltered meteorite. Here are scans of a slice I obtained from Marcin: http://img.photobucket.com/albums/v614/CaneySprings/NWA2826LL528gmMarcinCi mala.jpg http://img.photobucket.com/albums/v614/CaneySprings/NWA2826LL528gmMarcinCi malacloseup.jpg I assume that these fragments were dislodged late in flight while the crust was still liquid but too late to be melted or thermally altered. I would think that is just a darker clast in the rock that happened to be only on the outer edge of that slice. __ 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 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 mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Rocks From Space Picture of the Day
http://www.spacerocksinc.com/March_23.html ** AOL now offers free email to everyone. Find out more about what's free from AOL at http://www.aol.com. __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Auction ending soon!
Dear list members, I have two items ending soon. These are AAA+ quality specimens: http://search.ebay.com/_W0QQsassZspacerocksincQQhtZ-1 Sincerely, Michael Johnson SPACEROCKSINC.COM http://www.spacerocksinc.com SIKHOTE-ALIN.ORG http://www.sikhote-alin.org ** AOL now offers free email to everyone. Find out more about what's free from AOL at http://www.aol.com. __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Fusion crusts on stony meteorites
Hi All, I bought a slice of this meteorite from Marcin at Tucson. While I am not a professional meteoriticist, I am an engineer heavily involved with failure analysis, use of microscopes and a trained observer. To my eye these are most definitely small bits of this meteorite fractured off of the parent body during transit of the atmosphere and incorporated in the fusion crust, likely on the back side of the meteorite. I had to have this slice the minute that ET pointed out to me this interesting feature! Thanks to ET for the heads up and thanks to Marcin for doing an excellent job of slicing and polishing this meteorite and offering it for sale. Pat --- Darren Garrison [EMAIL PROTECTED] wrote: On Thu, 22 Mar 2007 22:05:51 -0700, you wrote: Michael, Darren, Jim and list, I agree with Jim on this. My slice of the same stone has fragments set in a clearly bubbly melt. I suggest that this accumulated on the back side of the stone during oriented flight. Check out my pictures: http://www.johnkashuba.com/Pages/Meteorite%20Pages/Pictures/NWA2826LL5.htm This photo does look pretty convincing-- the triangular fragment in the melt looks like like a close match to the bigger mass: http://www.johnkashuba.com/Images/Meteorite%20Pages/Pictures/[EMAIL PROTECTED] __ 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] Fusion crusts on stony meteorites
That may well be, there is no substitute to holding a piece in your hands to see it best. There are many oriented meteorites which exhibit the thick frothy crust on the backside, and many pieces have broken fragments re-solidified into the crust, so this must be one of them. Michael Farmer --- Pat Brown [EMAIL PROTECTED] wrote: Hi All, I bought a slice of this meteorite from Marcin at Tucson. While I am not a professional meteoriticist, I am an engineer heavily involved with failure analysis, use of microscopes and a trained observer. To my eye these are most definitely small bits of this meteorite fractured off of the parent body during transit of the atmosphere and incorporated in the fusion crust, likely on the back side of the meteorite. I had to have this slice the minute that ET pointed out to me this interesting feature! Thanks to ET for the heads up and thanks to Marcin for doing an excellent job of slicing and polishing this meteorite and offering it for sale. Pat --- Darren Garrison [EMAIL PROTECTED] wrote: On Thu, 22 Mar 2007 22:05:51 -0700, you wrote: Michael, Darren, Jim and list, I agree with Jim on this. My slice of the same stone has fragments set in a clearly bubbly melt. I suggest that this accumulated on the back side of the stone during oriented flight. Check out my pictures: http://www.johnkashuba.com/Pages/Meteorite%20Pages/Pictures/NWA2826LL5.htm This photo does look pretty convincing-- the triangular fragment in the melt looks like like a close match to the bigger mass: http://www.johnkashuba.com/Images/Meteorite%20Pages/Pictures/[EMAIL PROTECTED] __ 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 mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Mars Odyssey THEMIS Images: March 19-23, 2007
MARS ODYSSEY THEMIS IMAGES March 19-23, 2007 o Landslide (Released 19 March 2007) http://themis.asu.edu/zoom-20070319a o Sand Dunes (Released 20 March 2007) http://themis.asu.edu/zoom-20070320a o Sand Dunes (Released 21 March 2007) http://themis.asu.edu/zoom-20070321a o Dust and Land Slides (Released 22 March 2007) http://themis.asu.edu/zoom-20070322a o Polar Textures (Released 23 March 2007) http://themis.asu.edu/zoom-20070323a 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. __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] AD: New meteorite coin minted for Campo del Cielo
Hello list members. Today I am announcing a new item, meteorite coins commemorating Camp del Cielo, with actual pieces of the meteorite embedded in the crater on the coin. Jim Strope and I had these designed and minted for the Tucson show, but the production was delayed and they did not arrive until the last day of the show. http://www.meteoritecoins.com/ TODAY and TODAY only, I am making an offer to list members, CHOOSE your own number. I am excluding #s 1-10 all 100 200 300 etc #s, and #1000. These are special numbers which will be auctioned off later for special causes. There was a limited minting of 1000 coins, no more will be made. The price is $25.00 including shipping WORLDWIDE. __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] [Fwd: Re: Fusion crusts on stony meteorites]
Dave asked me to post this message to the list. Regards, Jim Baxter Original Message Subject: Re: [meteorite-list] Fusion crusts on stony meteorites From: David Johnson [EMAIL PROTECTED] Date: Thu, March 22, 2007 10:58 pm To: [EMAIL PROTECTED] Hello Jim, I find your post and pictures from Marcin Cimala interesting, as I've submitted an article to Meteorite Magazine that notes two accounts of particles, on the order of 1mm in size, impacting my house and another house closer to the Park Forest strewnfield during the fall of the Park Forest meteorite. The pictures you posted provides visual proof that such a phenomenon does occur quite nicely, and helps show how the diminutive particles that were heard/seen were able to be produced during the ablation. My article only touches upon the phenomenon as being reported, without going into any analysis of how it occurs. Perhaps this will open up further studies into the effects of ablation. Would you please post this to the meteorite list as well? I used to be a member, but apparently have been removed due to mail bouncing, although the account I used for sign-up has been open all the while. Thanks, Dave Johnson Hello Jim, I find your post and pictures from Marcin Cimala interesting, as Ive submitted an article to Meteorite Magazine that notes two accounts of particles, on the order of 1mm in size, impacting my house and another house closer to the Park Forest strewnfield during the fall of the Park Forest meteorite. The pictures you posted provides visual proof that such a phenomenon does occur quite nicely, and helps show how the diminutive particles that were heard/seen were able to be produced during the ablation. My article only touches upon the phenomenon as being reported, without going into any analysis of how it occurs. Perhaps this will open up further studies into the effects of ablation. Would you please post this to the meteorite list as well? I used to be a member, but apparently have been removed due to mail bouncing, although the account I used for sign-up has been open all the while. Thanks,Dave Johnson __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] NWA METEORITES SHOP
TEST AOL now offers free email to everyone. Find out more about what's free from AOL at AOL.com. __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] eBay winner!
I wanted my own copy of the Norton classic, so risked buying one on eBay. It arrived and although the binding is a bit torn (worn by rocks?) I was quite surprised to see that it was a SIGNED copy, by both the author and his wife ! (She did the illustrations as you all probably know.) How pleased I am right now!Thats almost as good a feeling as finding a meteorite!!! Robin Happy Camper in TN. __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] PolandMET page update [AD]
Excellent site. Congratulations. AA - Original Message - From: PolandMET [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Thursday, March 22, 2007 7:54 PM Subject: [meteorite-list] PolandMET page update [AD] Hello List Members. I have put new material on my page www.PolandMET.com CANYON DIABLO GRAPHITE NODULES [IAB] - slices from 1400g specimen DHOFAR 007 [AEUC] - two new large slices NWA4560 [LL3.7] - new big full slices JUANCHENG [H5] - Fall from China. Slices and specimens with brecciation. -[ MARCIN CIMALA ]-[ I.M.C.A.#3667 ]- http://www.Meteoryt.net [EMAIL PROTECTED] http://www.PolandMET.com [EMAIL PROTECTED] http://www.Gao-Guenie.com GSM +48(607)535 195 [ Member of Polish Meteoritical Society ] __ 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] Fusion crusts on stony meteorites
porphyritic? Are you sure? The meteorites cool down in a single stage, I believe. AA - Original Message - From: [EMAIL PROTECTED] To: Meteorite-list@meteoritecentral.com Sent: Thursday, March 22, 2007 5:35 PM Subject: [meteorite-list] Fusion crusts on stony meteorites GENGE M.J. and GRADY M. (1999) The fusion crusts of stony meteorites: implications for the atmospheric reprocessing of extra- terrestrial materials (MAPS 34-3, 1999, 341-356): a) Fusion crusts develop on *all* meteorites during their passage of the atmosphere ... b) Most chondrite fusion crusts are porphyritic and dominated by olivine, glass and accessory magnetite whereas those of the achondrites are mainly glassy. c) Chondrite fusion crusts contain sulphide droplets with high-Ni contents (55 wt%). d) The partially melted substrate of OCs, underlying the outer melted crusts, are dominated by silicate glass and composite metal, sulphide and Cr-bearing Fe-oxide droplets that form as coexisting immiscible liquids. e) Enstatite chondrite substrates contain Cr- and Mn- bearing sulphides. f) The substrates of the CCs comprise a sulphide-enriched layer of matrix. The compositions of melted crusts are similar to those of the bulk meteorite. Differences from whole rock, however, suggest that three main processes control their chemical evolution: 1) the loss and reaction of immiscible Fe-rich liquids, 2) mixing between substrate partial melts and bulk melts of the melted crust, 3) the loss of volatile components by evaporation and degassing. Conclusions, p. 356: The fusion crusts of stony meteorites exhibit considerable variation with meteorite type and compositions and textures that are largely dependent on the bulk chemical and mineralogical properties of the meteorite. Four processes are important in the chemical evolution of fusion crusts: 1) the separation and reaction of Fe-rich sulphide, metal, and oxide liquids, 2) reaction with atmospheric O, 3) mixing of incompatible element-rich partial melts from the substrate with bulk melted crust liquid, 4) the loss of volatile elements by e v a p o r a t i o n and d e g a s s i n g. Best wishes, Bernd __ 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] a question on fusion crust
Of course it is fusion crust. We agree on something, finally. I only wanted to underline that question of the material beeing the same or not. Magnetite is a diferent substance, resulting of the combination with the atmosphere, and much harder than the Iron from where it came. Speaking of fake crusts on chondrites (since it can be done easily with a blowpipe) I am sure that some enterpreneur already sold one or two... To coat of magnetite an iron meteorite, is a bit more dificult to produce in the garage. Perhaps someone on the list could tell us something interesting about this. AA - Original Message - From: Michael Farmer [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Thursday, March 22, 2007 5:04 PM Subject: Re: [meteorite-list] a question on fusion crust Crus is crust, soft, hard, it doesnt matter. It is a crust of material caused to be on the surface of the object by fusion. Why would iron fusion crut not be different than that of stones? Of course it is chemically different. You know, you can remove the fusion crust on some stones easily as well, so what if most of the crust on irons is softer, and can fake off easily. The subsurface is smooth, and much more difficult for the crust to adhere to. Go to Vienna and check out Cabin Creek, 100% blue-black fusion crust on the most beautiful iron fall I have ever seen. It is not rust, nothing but a crust caused by intense burning in the atmosphere. You can debate over the chemical composition of the heat altered layer on the surface of irons all you want, but it is fusion crust. Michael Farmer --- Armando Afonso [EMAIL PROTECTED] wrote: In that case, you get a vitrification of the silicates, with some inclusion of reduced iron, eventually coming from the pyroxenes or olivine, giving it the dark tone. Anyway, we are really speaking of diferent and new minerals. Normally that crust is harder than the meteorite in itself. AA - Original Message - From: Michael Farmer [EMAIL PROTECTED] To: Armando Afonso [EMAIL PROTECTED]; meteorite-list@meteoritecentral.com Sent: Thursday, March 22, 2007 4:48 PM Subject: Re: [meteorite-list] a question on fusion crust But made from the matrix component. burned material from the parent body, regardless of how it is chemically changed, same as the fusion crust on any meteorite. Take a Eucrite like Stannern for example, white interior, yet the fusion crust is glossy black. That is not soot, it is chemically altered matrix. Nothing more. Michael Farmer --- Armando Afonso [EMAIL PROTECTED] wrote: Obviously, it is a diferent material... The external fusion crust of iron meteorites is Magnetite, the result of the combination with the air`s oxygene. AA - Original Message - From: Michael Farmer [EMAIL PROTECTED] To: Mr EMan [EMAIL PROTECTED]; Michael Murray [EMAIL PROTECTED]; Meteorite-list@meteoritecentral.com Sent: Thursday, March 22, 2007 4:14 PM Subject: Re: [meteorite-list] a question on fusion crust This is simple. Fusion, the result of material burning at extreme temeratures, and crust, the layer on the surface that was not there before re-entry. Thus, FUSION CRUST It is quite obvious that the surface of a freshly fallen iron, with the blue-black coating is a FUSION CRUST. It generally can't be wiped off. I have pieces in my collection, Bugoslava for example, with a .5 mm layer of blue-black fusion crust, that survived cutting and polishing of the meteorite, so it is not exacly soot. Of course the crust is the same as the parent material, even on stones. How could it be of a different material? How could an object, falling through the atmosphere, get coated with anything but it's own matrix as it burns? Yes, the silicates can be altered due to heating, while irons tend not to chemically alter. Elton, I think you are about the only one in the world that thinks fresh fallen iron meteorites do not have fusion crust. Michael Farmer --- Mr EMan [EMAIL PROTECTED] wrote: The soot coating you are talking about is mostly freshly created magnetite (micro /nano crystals) from the oxidation of iron whilst passing through the incandescent phase. It adheres by magnetism and can be wiped off with rough handling. There is probably a carbon component however graphite turns to carbon dioxide upon burning There are several other terms for the zone associated with ablation heating, one of which is in the literature: zone of thermal alteration. When there is an oxidation coat . native elements such as found on sodium or phosphorus it is sometimes called a rind. This is what I favor to describe the coatings on irons--the one before terrestrial oxidation also known as rust. In my view there can
Re: [meteorite-list] a question on fusion crust
In that case, you get a vitrification of the silicates, with some inclusion of reduced iron, eventually coming from the pyroxenes or olivine, giving it the dark tone. Anyway, we are really speaking of diferent and new minerals. Normally that crust is harder than the meteorite in itself. AA - Original Message - From: Michael Farmer [EMAIL PROTECTED] To: Armando Afonso [EMAIL PROTECTED]; meteorite-list@meteoritecentral.com Sent: Thursday, March 22, 2007 4:48 PM Subject: Re: [meteorite-list] a question on fusion crust But made from the matrix component. burned material from the parent body, regardless of how it is chemically changed, same as the fusion crust on any meteorite. Take a Eucrite like Stannern for example, white interior, yet the fusion crust is glossy black. That is not soot, it is chemically altered matrix. Nothing more. Michael Farmer --- Armando Afonso [EMAIL PROTECTED] wrote: Obviously, it is a diferent material... The external fusion crust of iron meteorites is Magnetite, the result of the combination with the air`s oxygene. AA - Original Message - From: Michael Farmer [EMAIL PROTECTED] To: Mr EMan [EMAIL PROTECTED]; Michael Murray [EMAIL PROTECTED]; Meteorite-list@meteoritecentral.com Sent: Thursday, March 22, 2007 4:14 PM Subject: Re: [meteorite-list] a question on fusion crust This is simple. Fusion, the result of material burning at extreme temeratures, and crust, the layer on the surface that was not there before re-entry. Thus, FUSION CRUST It is quite obvious that the surface of a freshly fallen iron, with the blue-black coating is a FUSION CRUST. It generally can't be wiped off. I have pieces in my collection, Bugoslava for example, with a .5 mm layer of blue-black fusion crust, that survived cutting and polishing of the meteorite, so it is not exacly soot. Of course the crust is the same as the parent material, even on stones. How could it be of a different material? How could an object, falling through the atmosphere, get coated with anything but it's own matrix as it burns? Yes, the silicates can be altered due to heating, while irons tend not to chemically alter. Elton, I think you are about the only one in the world that thinks fresh fallen iron meteorites do not have fusion crust. Michael Farmer --- Mr EMan [EMAIL PROTECTED] wrote: The soot coating you are talking about is mostly freshly created magnetite (micro /nano crystals) from the oxidation of iron whilst passing through the incandescent phase. It adheres by magnetism and can be wiped off with rough handling. There is probably a carbon component however graphite turns to carbon dioxide upon burning There are several other terms for the zone associated with ablation heating, one of which is in the literature: zone of thermal alteration. When there is an oxidation coat . native elements such as found on sodium or phosphorus it is sometimes called a rind. This is what I favor to describe the coatings on irons--the one before terrestrial oxidation also known as rust. In my view there can be no crust when the chemical and physical characteristics of the surface do not differ from the donor material. That lets the door open for irons having crust and at least most agree that it is unlike the fusion crust of stoney meteorites. While at the Smithsonian inspecting the collection up close and personally, I was advised to use caution in examining a fresh iron as the coating would rub off easily. They didn't call it fusion crust but the issue never came up. The point being, not everyone is in agreement nor is there universal usage. Critical analysis on the assumptions about fusion crust on irons would likely lead to a more descriptive table of composition and relate that to the metallurgy and chemical composition of the meteorite itself. In fact I believe research on crustal petrology would be reveling for all types of meteorites. I yet wonder why some lunarites have a brown bubbly crust. The crust of a iron meteorite on Mars will be different from one here and I'd like to know what to expect and why. Intuitively, I know there would be rare minerals such as nickel oxides,nitrates, phosphates perhaps even a sulphide and yes even O3 and O4 silicates. However current wisdom is that crust is crust ego no research needs to be contemplated-NOT. Some of the oft quoted god status experts who write of fusion crust on irons monitor this list and have remained curiously silent on the topic. I hope this topic is thought provoking for all parties. I suppose that the use of the term fusion crust universally with respect to irons is acceptable if one doesn't have a need for technical accuracy. One thing yet to be refuted here on the list is that the
Re: [meteorite-list] a question on fusion crust
In that case, you get a vitrification of the silicates, with some inclusion of reduced iron, eventually coming from the pyroxenes or olivine, giving it the dark tone. Anyway, we are really speaking of diferent and new minerals. Normally that crust is harder than the meteorite in itself. AA - Original Message - From: Michael Farmer [EMAIL PROTECTED] To: Armando Afonso [EMAIL PROTECTED]; meteorite-list@meteoritecentral.com Sent: Thursday, March 22, 2007 4:48 PM Subject: Re: [meteorite-list] a question on fusion crust But made from the matrix component. burned material from the parent body, regardless of how it is chemically changed, same as the fusion crust on any meteorite. Take a Eucrite like Stannern for example, white interior, yet the fusion crust is glossy black. That is not soot, it is chemically altered matrix. Nothing more. Michael Farmer --- Armando Afonso [EMAIL PROTECTED] wrote: Obviously, it is a diferent material... The external fusion crust of iron meteorites is Magnetite, the result of the combination with the air`s oxygene. AA - Original Message - From: Michael Farmer [EMAIL PROTECTED] To: Mr EMan [EMAIL PROTECTED]; Michael Murray [EMAIL PROTECTED]; Meteorite-list@meteoritecentral.com Sent: Thursday, March 22, 2007 4:14 PM Subject: Re: [meteorite-list] a question on fusion crust This is simple. Fusion, the result of material burning at extreme temeratures, and crust, the layer on the surface that was not there before re-entry. Thus, FUSION CRUST It is quite obvious that the surface of a freshly fallen iron, with the blue-black coating is a FUSION CRUST. It generally can't be wiped off. I have pieces in my collection, Bugoslava for example, with a .5 mm layer of blue-black fusion crust, that survived cutting and polishing of the meteorite, so it is not exacly soot. Of course the crust is the same as the parent material, even on stones. How could it be of a different material? How could an object, falling through the atmosphere, get coated with anything but it's own matrix as it burns? Yes, the silicates can be altered due to heating, while irons tend not to chemically alter. Elton, I think you are about the only one in the world that thinks fresh fallen iron meteorites do not have fusion crust. Michael Farmer --- Mr EMan [EMAIL PROTECTED] wrote: The soot coating you are talking about is mostly freshly created magnetite (micro /nano crystals) from the oxidation of iron whilst passing through the incandescent phase. It adheres by magnetism and can be wiped off with rough handling. There is probably a carbon component however graphite turns to carbon dioxide upon burning There are several other terms for the zone associated with ablation heating, one of which is in the literature: zone of thermal alteration. When there is an oxidation coat . native elements such as found on sodium or phosphorus it is sometimes called a rind. This is what I favor to describe the coatings on irons--the one before terrestrial oxidation also known as rust. In my view there can be no crust when the chemical and physical characteristics of the surface do not differ from the donor material. That lets the door open for irons having crust and at least most agree that it is unlike the fusion crust of stoney meteorites. While at the Smithsonian inspecting the collection up close and personally, I was advised to use caution in examining a fresh iron as the coating would rub off easily. They didn't call it fusion crust but the issue never came up. The point being, not everyone is in agreement nor is there universal usage. Critical analysis on the assumptions about fusion crust on irons would likely lead to a more descriptive table of composition and relate that to the metallurgy and chemical composition of the meteorite itself. In fact I believe research on crustal petrology would be reveling for all types of meteorites. I yet wonder why some lunarites have a brown bubbly crust. The crust of a iron meteorite on Mars will be different from one here and I'd like to know what to expect and why. Intuitively, I know there would be rare minerals such as nickel oxides,nitrates, phosphates perhaps even a sulphide and yes even O3 and O4 silicates. However current wisdom is that crust is crust ego no research needs to be contemplated-NOT. Some of the oft quoted god status experts who write of fusion crust on irons monitor this list and have remained curiously silent on the topic. I hope this topic is thought provoking for all parties. I suppose that the use of the term fusion crust universally with respect to irons is acceptable if one doesn't have a need for technical accuracy. One thing yet to be refuted here on the list is that the
Re: [meteorite-list] a question on fusion crust
Obviously, it is a diferent material... The external fusion crust of iron meteorites is Magnetite, the result of the combination with the air`s oxygene. AA - Original Message - From: Michael Farmer [EMAIL PROTECTED] To: Mr EMan [EMAIL PROTECTED]; Michael Murray [EMAIL PROTECTED]; Meteorite-list@meteoritecentral.com Sent: Thursday, March 22, 2007 4:14 PM Subject: Re: [meteorite-list] a question on fusion crust This is simple. Fusion, the result of material burning at extreme temeratures, and crust, the layer on the surface that was not there before re-entry. Thus, FUSION CRUST It is quite obvious that the surface of a freshly fallen iron, with the blue-black coating is a FUSION CRUST. It generally can't be wiped off. I have pieces in my collection, Bugoslava for example, with a .5 mm layer of blue-black fusion crust, that survived cutting and polishing of the meteorite, so it is not exacly soot. Of course the crust is the same as the parent material, even on stones. How could it be of a different material? How could an object, falling through the atmosphere, get coated with anything but it's own matrix as it burns? Yes, the silicates can be altered due to heating, while irons tend not to chemically alter. Elton, I think you are about the only one in the world that thinks fresh fallen iron meteorites do not have fusion crust. Michael Farmer --- Mr EMan [EMAIL PROTECTED] wrote: The soot coating you are talking about is mostly freshly created magnetite (micro /nano crystals) from the oxidation of iron whilst passing through the incandescent phase. It adheres by magnetism and can be wiped off with rough handling. There is probably a carbon component however graphite turns to carbon dioxide upon burning There are several other terms for the zone associated with ablation heating, one of which is in the literature: zone of thermal alteration. When there is an oxidation coat . native elements such as found on sodium or phosphorus it is sometimes called a rind. This is what I favor to describe the coatings on irons--the one before terrestrial oxidation also known as rust. In my view there can be no crust when the chemical and physical characteristics of the surface do not differ from the donor material. That lets the door open for irons having crust and at least most agree that it is unlike the fusion crust of stoney meteorites. While at the Smithsonian inspecting the collection up close and personally, I was advised to use caution in examining a fresh iron as the coating would rub off easily. They didn't call it fusion crust but the issue never came up. The point being, not everyone is in agreement nor is there universal usage. Critical analysis on the assumptions about fusion crust on irons would likely lead to a more descriptive table of composition and relate that to the metallurgy and chemical composition of the meteorite itself. In fact I believe research on crustal petrology would be reveling for all types of meteorites. I yet wonder why some lunarites have a brown bubbly crust. The crust of a iron meteorite on Mars will be different from one here and I'd like to know what to expect and why. Intuitively, I know there would be rare minerals such as nickel oxides,nitrates, phosphates perhaps even a sulphide and yes even O3 and O4 silicates. However current wisdom is that crust is crust ego no research needs to be contemplated-NOT. Some of the oft quoted god status experts who write of fusion crust on irons monitor this list and have remained curiously silent on the topic. I hope this topic is thought provoking for all parties. I suppose that the use of the term fusion crust universally with respect to irons is acceptable if one doesn't have a need for technical accuracy. One thing yet to be refuted here on the list is that the crust on irons is not composed of glass. Elton --- Michael Murray [EMAIL PROTECTED] wrote: Hi List, Are you ready for a dumb question! Here goes... Is there a more definitive description of the blackened outer layer on the surface of iron meteorites than simply referring to it as fusion crust? From what I can gather looking at different pictures of stonys, they seem to have a glassy or melted layer of the material of the stone. I can see that being a 'crust'. On at least some irons, there is a coating but it doesn't appear glassy, just blackened. I'm guessing that that coating is partially resulting from burning of the gases in the atmosphere? If it is a 'crust', it is not much of one. It looks like a very thin coating of soot that is adhered to the stone, although more durable than soot. This is probably one of those dumb questions that the Collection of Wisdom would answer. The stone in this picture has the blackened layer I'm referring to: http://i127.photobucket.com/albums/p124/mmurray_02/IMG_0319.jpg
[meteorite-list] Delay and porphyritic
What can be the reason for this messages to appear with a delay of 32h? AA porphyritic? Are you sure? The meteorites cool down in a single stage, I believe Hi Armando and List, No idea why there is such a delay! Furthermore, I do not know for sure about the porphyritic thing. This was not my personal comment but I only quoted from the article by Genge and Monica Grady. But Dr. Monica Grady is a List member, so, time permitting, Dr. Grady might perhaps find some spare moments to answer your question much more competently than I ever would be able to! Best wishes, Bernd __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Delay and porphyritic
Armando , Bernd, all, Porphyritic is a textural term. In terrestrial igneous rocks it results from multiple-stage cooling, but I see no reason why you can't run it backwards with incomplete melting. If olivine is the common phenocryst phase, this would make sense in that it has an extremely high melting point. The glass would reflect the lower melting point silicates, while the olivine and magnetite remain, yielding a porphyritic texture. Cheers, Norm (http://TektiteSource.com) --- [EMAIL PROTECTED] wrote: What can be the reason for this messages to appear with a delay of 32h? AA porphyritic? Are you sure? The meteorites cool down in a single stage, I believe Hi Armando and List, No idea why there is such a delay! Furthermore, I do not know for sure about the porphyritic thing. This was not my personal comment but I only quoted from the article by Genge and Monica Grady. But Dr. Monica Grady is a List member, so, time permitting, Dr. Grady might perhaps find some spare moments to answer your question much more competently than I ever would be able to! Best wishes, Bernd __ 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] Ad: Meteorite coin sale choose your # extended
Hi everyone, I will be out of the house most of the evening, and the coin requests keep pouring in. I will extend the oppurtunity to choose your own number through the weekend to make it easier on myself and customers who may not have seen the emails yet. Michael Farmer http://www.meteoritecoins.com/ __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Fusion crusts on stony meteorites - NWA 2826
Hello Jim, John, Marcin and List, http://img.photobucket.com/albums/v614/CaneySprings/ http://img.photobucket.com/albums/v614/CaneySprings/ http://www.johnkashuba.com/Pages/Meteorite%20Pages/Pictures/NWA2826LL5.htm No matter what it is: fusion crust, impact melt, darker material, one thing is sure: It's one stunning LL5 chondrite with gorgeous crust and beautiful, well-developed thumbprints! John is such an experienced observer and photographer of meteoritic details that I have no problems joining his assessment: it does indeed look like matrix material surrrounded by fusion crust melt! Thanks for sharing ! Bernd P.S.: Marcin still has a few slices for sale but if you should have fallen in love with the 132 gram crusted fragment - too late because I have just bought it ;-) http://www.polandmet.com/_nwa2826.htm __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Fusion crusts on stony meteorites
I thought you and the list members might find interesting a phenomenon that was shown to me by Marcin Cimala. In cutting an LL5 he found areas where thick crust had built up and actually incorporated within the crust small angular fragments of relatively unaltered meteorite. Here are scans of a slice I obtained from Marcin: http://img.photobucket.com/albums/v614/CaneySprings/NWA2826LL528gmMarcinCimala.jpg http://img.photobucket.com/albums/v614/CaneySprings/NWA2826LL528gmMarcinCimalacloseup.jpgI see that I have missed topic about my meteorite.Mike, Darren, You are not right. This part is the back side of orientesstone.When uncut, it looks strange, it was very unequal. Much different than theother side, full of regmaglyptes.It is here, on third photo on the left. This is part that I have cut beforeTucson.http://www.polandmet.com/gfx_nwa2826/000.htmCrust here is thick becouse of orientation. But I have no idea how thissmall fragments can jump into liquid crust in the air and they have stillsharp edges, not burned. That a very cool one.-[ MARCIN CIMALA ]-[ I.M.C.A.#3667 ]-http://www.Meteoryt.net [EMAIL PROTECTED]://www.PolandMET.com [EMAIL PROTECTED]://www.Gao-Guenie.com GSM +48(607)535 195[ Member of Polish Meteoritical Society ] __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Fusion crusts on stony meteorites
On Sat, 24 Mar 2007 03:14:41 +0100, you wrote: But I have no idea how thissmall fragments can jump into liquid crust in the air and they have stillsharp edges, not burned. http://img.photobucket.com/albums/v614/CaneySprings/NWA2826LL528gmMarcinCimalacloseup.jpg Okay, here's an idea-- the meteorite looks to be filled with cracks-- maybe heat managed to flow through one of the pre-existing seams and get deeper into the meteorite than it ordinarily would, and surround bits of the matrix from behind. I know I have (and probably most of you have) fully-crusted individuals with deep (but still crusted) grooves in them that apparently formed by burning into cracks in the material. __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] took the crust off
I just took the Crust off the link and it works fine. Way-cool pictures Marcin. Thanks for sharing. Mike __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Fusion crusts on stony meteorites
I thought you and the list members might find interesting a phenomenon that was shown to me by Marcin Cimala. In cutting an LL5 he found areas where thick crust had built up and actually incorporated within the crust small angular fragments of relatively unaltered meteorite. Here are scans of a slice I obtained from Marcin: http://img.photobucket.com/albums/v614/CaneySprings/NWA2826LL528gmMarcinCimala.jpg http://img.photobucket.com/albums/v614/CaneySprings/NWA2826LL528gmMarcinCimalacloseup.jpgI see that I have missed topic about my meteorite.Mike, Darren, You are not right.This part is the back side of oriented stone.When uncut, it looks strange,it was very unequal. Much different than the other side, full ofregmaglyptes. This crusted part is here, on third photo on the left. This ispart that I have cut before Tucson.http://www.polandmet.com/gfx_nwa2826/000.htmCrust here is thick becouse of orientation. But I have no idea how thissmallfragments can jump into liquid crust in the air and they have still sharpedges, not burned. That a very cool one.sorry, last email was messed up some how.-[ MARCIN CIMALA ]-[ I.M.C.A.#3667 ]-http://www.Meteoryt.net [EMAIL PROTECTED]://www.PolandMET.com [EMAIL PROTECTED]://www.Gao-Guenie.com GSM +48(607)535 195[ Member of Polish Meteoritical Society ] __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Fusion crusts on stony meteorites
Hello all, Looking at crust on various thin sections under the microscope it is very common to see a mineral, such as an olvine crystal, on top of the crust. It is not as even as it appears to our naked eyes. A few old photographs on my website illustrate this fairly well... http://www.meteoritearticles.com/colthinsectioncrust.html Here is the crust on an oriented Gao-Guenie... http://www.meteoritearticles.com/znpgaots.html Clear Skies, Mark Bostick www.meteoritearticles.com __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Fusion crusts on stony meteorites
Hi list, Tom Phillips here, I have some crust micrographs taken in reflected cross polarized light of a thick slice of NWA 2371 an H4. The heating/cooling caused the crust to crystallize like nothing I have seen before. I haven't posted them to the Gallery yet but it is well worth the time to email me and I will send some shots in an email. I would welcome any thoughts on this and if any one has noticed it before. It really is cool! In a message dated 3/23/2007 8:44:45 P.M. Mountain Daylight Time, [EMAIL PROTECTED] writes: Hello all, Looking at crust on various thin sections under the microscope it is very common to see a mineral, such as an olvine crystal, on top of the crust. It is not as even as it appears to our naked eyes. A few old photographs on my website illustrate this fairly well... http://www.meteoritearticles.com/colthinsectioncrust.html Here is the crust on an oriented Gao-Guenie... http://www.meteoritearticles.com/znpgaots.html Clear Skies, Mark Bostick www.meteoritearticles.com ** AOL now offers free email to everyone. Find out more about what's free from AOL at http://www.aol.com. __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Fusion crusts on stony meteorites
Some spies melting my emails to the list. Here is my personal collection full slice of NWA 2826. It have also this thick crust but not soo beautifull as on some other slices, but I have hold it as it was the only one full slice that contain soul of this LL5. Big troilites, one big chondrule?, large unknown dark inclusions and shock veins. I have leave photos in original size for better view, but it is only 2M pix so they are not soo sharp. Some fragments was glued back together becouse they was broken while cutting but fortunatelly I was able to find them and put together like puzzles. There are also interesting two different inclusions in this slice. This large dark one on the bottom side and one grey on the center right. slice is around 9cm wide === http://www.meteoryt.net/ebay/P0019261.JPG http://www.meteoryt.net/ebay/P0019262.JPG macro view http://www.meteoryt.net/ebay/P0019263.JPG http://www.meteoryt.net/ebay/P0019264.JPG http://www.meteoryt.net/ebay/P0019265.JPG http://www.meteoryt.net/ebay/P0019266.JPG http://www.meteoryt.net/ebay/P0019267.JPG http://www.meteoryt.net/ebay/P0019268.JPG http://www.meteoryt.net/ebay/P0019269.JPG -[ MARCIN CIMALA ]-[ I.M.C.A.#3667 ]- http://www.Meteoryt.net [EMAIL PROTECTED] http://www.PolandMET.com [EMAIL PROTECTED] http://www.Gao-Guenie.com GSM +48(607)535 195 [ Member of Polish Meteoritical Society ] __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Crust Micrographs NWA 2371 Crystal Structure! Check it out!
Hi list, Tom Phillips here, I have some crust micrographs taken in reflected cross polarized light of a thick slice of NWA 2371 an H4. The heating/cooling caused the crust to crystallize like nothing I have seen before. I haven't posted them to the Gallery yet but it is well worth the time to email me and I will send some shots in an email. I would welcome any thoughts on this and if any one has noticed it before. It really is cool! If this hits the list more than once tonight, I forgot to send as text only so I sent it again. Tom In a message dated 3/23/2007 8:44:45 P.M. Mountain Daylight Time, [EMAIL PROTECTED] writes: Hello all, Looking at crust on various thin sections under the microscope it is very common to see a mineral, such as an olvine crystal, on top of the crust. It is not as even as it appears to our naked eyes. A few old photographs on my website illustrate this fairly well... http://www.meteoritearticles.com/colthinsectioncrust.html Here is the crust on an oriented Gao-Guenie... http://www.meteoritearticles.com/znpgaots.html Clear Skies, Mark Bostick www.meteoritearticles.com ** AOL now offers free email to everyone. Find out more about what's free from AOL at http://www.aol.com. __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Crust Micrographs NWA 2371 Crystal Structure! Check it out!
Taking time out during my expedition to the Wetumpaka astrobleme... --- [EMAIL PROTECTED] wrote: The heating/ cooling caused the crust to crystallize like nothing I have seen before... Not picking on you Tom but I am using this as a segway to speak to fusion crust again. One of the reasons I am so passionate is that I am tired of seeing all these weathered and rusty meteorites on Ebay described as having great fusion crust. I await the photographs, your collection is truly awesome. When you said crystalized, perhaps you meant solidified A technical point but important in truly understanding what fusion crust is and is not. By definition, meteorite crust can't re-crystallize but it may contain partially melted material. Silicate melt which is what comes from Common Chondrites is known as glass in the technical sense, meaning it is an amorphous solid-- (i.e. lacking crystal structure, e.g tektite, obsidian) This glass lacked the conditions of time and temperature to allow the molecules of like compounds to regroup in crystal form. Given the right conditions molecules tend to reform crystals. Notice how long it takes honey to turn to sugar crystals at room temperature? Only here it would take eons to recrystalize and the material would long be weathered away before that. While I have Internet connection let me also mention that the word fusiondoes not refer to burning but refers to the technical term for the change of state from solid to liquid. Hence the technical term fusion temperature--meaning the temperature at which a solid melts. Hence the origin of the terms and definition fusion crust So what you are seeing, Tom, must have a different explanation. Else everything we know about physics has to be redefined. Elton __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
