Re: [meteorite-list] Nickel free metal in Meteorites
Jeff, Thank you for your well explained points. As I have said many times before, you would make an excellent teacher as your answers always stimulate more thoughts. On that note. you acknowledge that nickel free metal does exist but, from reduced metal and is very small. With all due respect. Isn't size a relative thing? I mean looking at things on our scale the size of Nickel free metal in chondrules is small. So, doesn't this means it could be bigger? Look no farther than our own planet. We are way different than other planets. I have been told by Scientists that the earth is so diverse that it makes identification of meteorites difficult. This because Earth can and does have so many different types of rocks. And this is just one planet. So, going back to scale. What if this Reducing of Fe O that turns it into nickel free iron happens to be really big? Say the scale more like Artares which makes Earth look like a grain of sand? Based on our current method of weeding out meteorwrongs we may never know if really big reduction occurs because as part of the weeding process we eliminate all metal objects that do not contain nickel. And this reduction process as you say is a known fact. I see more abstracts based on theory than on nickel free iron facts. Another size scale dilemma is also acknowledged in meteorites. They say ( tongue in cheek) this is either a very large inclusion and the rest of the meteorite is missing. Or this is the whole thing. This is the case with irons. Sometimes the iron is nearly pure and other times it is mixed with silicates as in meso's. But again the point is that these small bits of nickel free iron could be big but we will never know. It seems to me if we paid more attention to morphology and find location and less on nickel content (as a must) that we would discover an iron without nickel. Maybe not as big as Hoba but not as small as what was found in HAH 237 CBb either. I believe this nickel free iron was also found in one of the Kalahari Lunar's. Is that from a chondrule also? This particular meteorite HAH 237 is the one they used recently to reset the date of our solar system but not important enough to open our eyes to the lack of nickel in bigger meteorites. I don't get it? I understand there is always a story. This thing fell through the roof Okay, does it look man made? Does it have serial numbers on it? Is it identifiable as an object of any kind like a piece of a tree shredder blade? If these answers are no then maybe just maybe it did fall from the sky? (NJ meteorite). In this example it was determined to be possible space junk and yet nobody bothered to show which space object it could have come from. This object would have had a significant amount of not only monetary value but scientific as well. What was this stainless steel chunk of metal doing up in space? Why would NASA have misplaced such a strange piece of stainless steel? The science was dropped but, it came from somewhere. We may never know from where though. We dropped the ball on NJ and we may be dropping balls every day from a lack of nickel. Heaven forbid we find the first large nickel free iron! Obviously it would be rare but, there are known ungrouped irons that are equally rare. Just another question. Carl -- Carl or Debbie Esparza Meteoritemax Jeff Grossman jgross...@usgs.gov wrote: Ni-free metal occurs within chondrules that have experienced reduction during melting. These chondrules were originally mostly free of metal and therefore free of Ni, but contained oxidized iron (FeO) in the silicate minerals. During reduction, the FeO was converted into Fe metal (if the reducing agent was H2, then you'd also make H2O; if it was C then you'd make CO/CO2). The pure Fe metal that is made can manifest itself as dusty metal grains within olivine crystals, or sometimes can coalesce into larger Fe metal particles in the chondrule. The thing about this is, it is a local effect within a few chondrules. Most of the metal in the chondrite is still Ni-bearing. There is no easy way to make large masses of this pure Fe metal, such as would form iron meteorites, because any process that would segregate metal, would segregate all of it, not just these strange particles. Jeff On 2010-03-25 5:59 PM, cdtuc...@cox.net wrote: List, During recent research into CBb chondrites I stumbled upon an article from 2007 with references from Rubin that shows an image of a CC chondrite with nickel free metal. How is this possible? In past conversations with Scientists when I have asked why do iron meteorites always have to have nickel. The typical response is that they not only have to have nickel but, it has to have a few percent of nickel and not just PPM's of it. In explanation of this as I recall, I've always been told the reason that meteoritic iron always has to have Nickel is because in nature there is no
Re: [meteorite-list] Nickel free metal in Meteorites
Low-Ni or Ni-free iron doesn't occur just in some chondrules. It is also found in impact-melt-rock clasts in ordinary chondrites and at the edges of olivine grains in ureilites. These rocks have experienced localized in situ reduction of FeO to metallic Fe as Jeff has pointed out. But let's look at the context, these low-Ni metallic iron grains are situated within mafic silicate grains that have lots of SiO2, MgO and (away from the reduced metal) FeO. They are formed in the solid state. A large iron meteorite isn't situated within a mass of mafic silicate. You could argue that it broke off, but this also wouldn't work. Diffusion of oxygen out of the iron mass would probably take longer than the age of the solar system. In addition, iron meteorite falls typically contain at least a few inclusions of troilite, schreibersite, cohenite, graphite, etc. that would not form by reduction of FeO. So, I'm afraid that I don't believe that we're missing real meteorites by categorizing Ni-free iron masses as meteor-wrongs. Alan - Original Message - From: cdtuc...@cox.net To: Jeff Grossman jgross...@usgs.gov; meteoritelist meteorite-list@meteoritecentral.com Sent: Friday, March 26, 2010 11:06 AM Subject: Re: [meteorite-list] Nickel free metal in Meteorites Jeff, Thank you for your well explained points. As I have said many times before, you would make an excellent teacher as your answers always stimulate more thoughts. On that note. you acknowledge that nickel free metal does exist but, from reduced metal and is very small. With all due respect. Isn't size a relative thing? I mean looking at things on our scale the size of Nickel free metal in chondrules is small. So, doesn't this means it could be bigger? Look no farther than our own planet. We are way different than other planets. I have been told by Scientists that the earth is so diverse that it makes identification of meteorites difficult. This because Earth can and does have so many different types of rocks. And this is just one planet. So, going back to scale. What if this Reducing of Fe O that turns it into nickel free iron happens to be really big? Say the scale more like Artares which makes Earth look like a grain of sand? Based on our current method of weeding out meteorwrongs we may never know if really big reduction occurs because as part of the weeding process we eliminate all metal objects that do not contain nickel. And this reduction process as you say is a known fact. I see more abstracts based on theory than on nickel free iron facts. Another size scale dilemma is also acknowledged in meteorites. They say ( tongue in cheek) this is either a very large inclusion and the rest of the meteorite is missing. Or this is the whole thing. This is the case with irons. Sometimes the iron is nearly pure and other times it is mixed with silicates as in meso's. But again the point is that these small bits of nickel free iron could be big but we will never know. It seems to me if we paid more attention to morphology and find location and less on nickel content (as a must) that we would discover an iron without nickel. Maybe not as big as Hoba but not as small as what was found in HAH 237 CBb either. I believe this nickel free iron was also found in one of the Kalahari Lunar's. Is that from a chondrule also? This particular meteorite HAH 237 is the one they used recently to reset the date of our solar system but not important enough to open our eyes to the lack of nickel in bigger meteorites. I don't get it? I understand there is always a story. This thing fell through the roof Okay, does it look man made? Does it have serial numbers on it? Is it identifiable as an object of any kind like a piece of a tree shredder blade? If these answers are no then maybe just maybe it did fall from the sky? (NJ meteorite). In this example it was determined to be possible space junk and yet nobody bothered to show which space object it could have come from. This object would have had a significant amount of not only monetary value but scientific as well. What was this stainless steel chunk of metal doing up in space? Why would NASA have misplaced such a strange piece of stainless steel? The science was dropped but, it came from somewhere. We may never know from where though. We dropped the ball on NJ and we may be dropping balls every day from a lack of nickel. Heaven forbid we find the first large nickel free iron! Obviously it would be rare but, there are known ungrouped irons that are equally rare. Just another question. Carl -- Carl or Debbie Esparza Meteoritemax Jeff Grossman jgross...@usgs.gov wrote: Ni-free metal occurs within chondrules that have experienced reduction during melting. These chondrules were originally mostly free of metal and therefore free of Ni, but contained oxidized iron (FeO) in the silicate minerals. During reduction, the FeO was converted into Fe metal
Re: [meteorite-list] Nickel free metal in Meteorites
Alan, Wow, I appreciate that your points are put in terms I can follow but Would you be so kind as to explain a bit better for me to understand? Again, I respect you enough to hear what you are saying but, you lost me in some of your points. I will question below in all caps. No, I'm not yelling. Thanks. -- Carl or Debbie Esparza Meteoritemax Alan Rubin aeru...@ucla.edu wrote: Low-Ni or Ni-free iron doesn't occur just in some chondrules. It is also found in impact-melt-rock clasts in ordinary chondrites and at the edges of olivine grains in ureilites. SO, THIS MAY EXPLAIN THE KALAHARI FIND OF THIS NICKEL FREE IRON? AND YOUR INPUT IS HIGHLY APPRECIATED HERE. These rocks have experienced localized in situ reduction of FeO to metallic Fe as Jeff has pointed out. But let's look at the context, these low-Ni metallic iron grains are situated within mafic silicate grains that have lots of SiO2, MgO and (away from the reduced metal) FeO. They are formed in the solid state. A large iron meteorite isn't situated within a mass of mafic silicate. You could argue that it broke off, but this also wouldn't work. Diffusion of oxygen out of the iron mass would probably take longer than the age of the solar system. ARE WE TALKING 13 BILLION YEARS HERE (BIG BANG) ? OR 4.6 BILLION? WHY COULD THIS NOT HAVE OCCURRED AT THE TIME OF BIG BANG .THIS WAS VERY HOT AND QUICK? In addition, iron meteorite falls typically contain at least a few inclusions of troilite, schreibersite, cohenite, graphite, etc. that would not form by reduction of FeO. RESPECTFULLY, EXACTLY MY POINT. HOW WOULD WE EVER KNOW IF THESE THINGS ARE IN A ROCK THAT WE DISMISS BECAUSE IT HAS NO NICKEL? SEEMS TO ME THERE SHOULD BE A BETTER WAY. So, I'm afraid that I don't believe that we're missing real meteorites by categorizing Ni-free iron masses as meteor-wrongs. JUST ASKING. I JUST DON'T GET HOW NICKEL IN AN IRON CAN BE 3 TO 60 PERCENT AND NOT ZERO PERCENT? ESPECIALLY NOW THAT WE KNOW ZERO PERCENT DOES EXIST IN SPACE. SOMETHING DIFFERENT MIGHT BE GOING ON? THANK YOU AGAIN FOR YOUR HELP. CARL Alan - Original Message - From: cdtuc...@cox.net To: Jeff Grossman jgross...@usgs.gov; meteoritelist meteorite-list@meteoritecentral.com Sent: Friday, March 26, 2010 11:06 AM Subject: Re: [meteorite-list] Nickel free metal in Meteorites Jeff, Thank you for your well explained points. As I have said many times before, you would make an excellent teacher as your answers always stimulate more thoughts. On that note. you acknowledge that nickel free metal does exist but, from reduced metal and is very small. With all due respect. Isn't size a relative thing? I mean looking at things on our scale the size of Nickel free metal in chondrules is small. So, doesn't this means it could be bigger? Look no farther than our own planet. We are way different than other planets. I have been told by Scientists that the earth is so diverse that it makes identification of meteorites difficult. This because Earth can and does have so many different types of rocks. And this is just one planet. So, going back to scale. What if this Reducing of Fe O that turns it into nickel free iron happens to be really big? Say the scale more like Artares which makes Earth look like a grain of sand? Based on our current method of weeding out meteorwrongs we may never know if really big reduction occurs because as part of the weeding process we eliminate all metal objects that do not contain nickel. And this reduction process as you say is a known fact. I see more abstracts based on theory than on nickel free iron facts. Another size scale dilemma is also acknowledged in meteorites. They say ( tongue in cheek) this is either a very large inclusion and the rest of the meteorite is missing. Or this is the whole thing. This is the case with irons. Sometimes the iron is nearly pure and other times it is mixed with silicates as in meso's. But again the point is that these small bits of nickel free iron could be big but we will never know. It seems to me if we paid more attention to morphology and find location and less on nickel content (as a must) that we would discover an iron without nickel. Maybe not as big as Hoba but not as small as what was found in HAH 237 CBb either. I believe this nickel free iron was also found in one of the Kalahari Lunar's. Is that from a chondrule also? This particular meteorite HAH 237 is the one they used recently to reset the date of our solar system but not important enough to open our eyes to the lack of nickel in bigger meteorites. I don't get it? I understand there is always a story. This thing fell through the roof Okay, does it look man made? Does it have serial numbers on it? Is it identifiable as an object of any kind like a piece of a tree shredder blade? If these answers
Re: [meteorite-list] Nickel free metal in Meteorites
- Original Message - From: cdtuc...@cox.net To: Alan Rubin aeru...@ucla.edu; meteoritelist meteorite-list@meteoritecentral.com Sent: Friday, March 26, 2010 12:23 PM Subject: Re: [meteorite-list] Nickel free metal in Meteorites Alan, Wow, I appreciate that your points are put in terms I can follow but Would you be so kind as to explain a bit better for me to understand? Again, I respect you enough to hear what you are saying but, you lost me in some of your points. I will question below in all caps. No, I'm not yelling. Thanks. -- Carl or Debbie Esparza Meteoritemax Alan Rubin aeru...@ucla.edu wrote: Low-Ni or Ni-free iron doesn't occur just in some chondrules. It is also found in impact-melt-rock clasts in ordinary chondrites and at the edges of olivine grains in ureilites. SO, THIS MAY EXPLAIN THE KALAHARI FIND OF THIS NICKEL FREE IRON? AND YOUR INPUT IS HIGHLY APPRECIATED HERE. I'm afraid I don't know anything about this. These rocks have experienced localized in situ reduction of FeO to metallic Fe as Jeff has pointed out. But let's look at the context, these low-Ni metallic iron grains are situated within mafic silicate grains that have lots of SiO2, MgO and (away from the reduced metal) FeO. They are formed in the solid state. A large iron meteorite isn't situated within a mass of mafic silicate. You could argue that it broke off, but this also wouldn't work. Diffusion of oxygen out of the iron mass would probably take longer than the age of the solar system. ARE WE TALKING 13 BILLION YEARS HERE (BIG BANG) ? OR 4.6 BILLION? WHY COULD THIS NOT HAVE OCCURRED AT THE TIME OF BIG BANG .THIS WAS VERY HOT AND QUICK? I was talking about the age of the solar system, circa 4.6 billion years. There was no iron at the time of the Big Bang: only hydrogen, helium and a little lithium. The heavier elements (up to iron) were forged later in stars by normal fusion processes and did not enter the interstellar medium until these stars died. Iron and heavier elements were made in supernova explosions of heavy stars and spewed into the interstellar medium. In addition, iron meteorite falls typically contain at least a few inclusions of troilite, schreibersite, cohenite, graphite, etc. that would not form by reduction of FeO. RESPECTFULLY, EXACTLY MY POINT. HOW WOULD WE EVER KNOW IF THESE THINGS ARE IN A ROCK THAT WE DISMISS BECAUSE IT HAS NO NICKEL? SEEMS TO ME THERE SHOULD BE A BETTER WAY. I have looked at a lot of iron meteorwrongs and they do not include troilite, schreibersite, and cohenite. So, I'm afraid that I don't believe that we're missing real meteorites by categorizing Ni-free iron masses as meteor-wrongs. JUST ASKING. I JUST DON'T GET HOW NICKEL IN AN IRON CAN BE 3 TO 60 PERCENT AND NOT ZERO PERCENT? ESPECIALLY NOW THAT WE KNOW ZERO PERCENT DOES EXIST IN SPACE. SOMETHING DIFFERENT MIGHT BE GOING ON? Metallic Fe can form in two ways. Cosmochemists surmise that at the beginning of solar-system history there was a hot and cooling gas of solar composition at low pressure. If we assume a certain pressure, say 1/10,000 of an atmosphere, the we can calculate the temperatures at which different elements condense as solids from the gas. Metallic Ni condenses at 1354 K; metallic Fe condenses at a slightly lower temperature, i.e., 1337 K. The iron is expected to condense on the Ni grains to form a solid solution of metallic Fe-Ni. As temperatures drop, these grains will coarsen. At much lower temperatures, some of the metallic Fe will react with oxygen and form FeO. This component is generally incorporated into silicate minerals. A chondrite will generally contain grains of metallic Fe-Ni and silicates that contain FeO. Except in the most oxidized chondrites, e.g., R and CK, there is little NiO in the olivine. So, when we have localized in situ reduction, we can form low-Ni metallic Fe from the silicates occurring inside the silicate grains. Please note that volumetrically, the amount of low-Ni metallic Fe is trivial, far less than 0.1% of a typical chondrite. The bulk of the metal grains outside these silicates will be largely unaffected, except that they may have somewhat enhanced Fe/Ni ratios at their margins. Bulk melting of these rocks will merge all of the metal and it will have essentially the cosmic Fe/Ni ratio. Igneous processes such as fractional crystallization in metallic magmas in the cores of differentiated asteroids will change the Fe/Ni ratio of different samples leading to the variety in the irons we see today. THANK YOU AGAIN FOR YOUR HELP. CARL Alan - Original Message - From: cdtuc...@cox.net To: Jeff Grossman jgross...@usgs.gov; meteoritelist meteorite-list@meteoritecentral.com Sent: Friday, March 26, 2010 11:06 AM Subject: Re: [meteorite-list] Nickel
Re: [meteorite-list] Nickel free metal in Meteorites
Hi Carl, Which Kalahari are you referring to? There are 9 in the Met Bull. I did a quick search on this list and google but didn't turn up any info on nickle free iron in the Kalahari. Thanks. Carl2 Carl wrote: ...SO, THIS MAY EXPLAIN THE KALAHARI FIND OF THIS NICKEL FREE IRON? AND YOUR INPUT IS HIGHLY APPRECIATED HERE... _ Hotmail: Trusted email with Microsoft’s powerful SPAM protection. http://clk.atdmt.com/GBL/go/210850552/direct/01/ __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Nickel free metal in Meteorites
List, During recent research into CBb chondrites I stumbled upon an article from 2007 with references from Rubin that shows an image of a CC chondrite with nickel free metal. How is this possible? In past conversations with Scientists when I have asked why do iron meteorites always have to have nickel. The typical response is that they not only have to have nickel but, it has to have a few percent of nickel and not just PPM's of it. In explanation of this as I recall, I've always been told the reason that meteoritic iron always has to have Nickel is because in nature there is no way to separate the two elements. If that is true then how is it that in this case we do in fact have meteoritic metal without nickel? somehow they got separated. Unless this analysis is wrong does this not teach us that yes in fact there can and does exist meteoritic iron devoid of nickel. And therefore there not only could be Iron meteorites without nickel but,this ups the odds that there in fact are meteorites without nickel. Please see attached abstract. Back scattered images Figure 2 at the fifth page from the top of the article. It says; D. Close up of a CC Chondrule texture. Radiating unidentified minerals and Nickel free metal (met) are set up in a silica-rich matrix. http://www2.mnhn.fr/hdt205/leme/doc/2007%20Gounelle%20et%20al.%20EPSL.pdf Thanks Carl -- Carl or Debbie Esparza Meteoritemax __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Nickel free metal in Meteorites
Ni-free metal occurs within chondrules that have experienced reduction during melting. These chondrules were originally mostly free of metal and therefore free of Ni, but contained oxidized iron (FeO) in the silicate minerals. During reduction, the FeO was converted into Fe metal (if the reducing agent was H2, then you'd also make H2O; if it was C then you'd make CO/CO2). The pure Fe metal that is made can manifest itself as dusty metal grains within olivine crystals, or sometimes can coalesce into larger Fe metal particles in the chondrule. The thing about this is, it is a local effect within a few chondrules. Most of the metal in the chondrite is still Ni-bearing. There is no easy way to make large masses of this pure Fe metal, such as would form iron meteorites, because any process that would segregate metal, would segregate all of it, not just these strange particles. Jeff On 2010-03-25 5:59 PM, cdtuc...@cox.net wrote: List, During recent research into CBb chondrites I stumbled upon an article from 2007 with references from Rubin that shows an image of a CC chondrite with nickel free metal. How is this possible? In past conversations with Scientists when I have asked why do iron meteorites always have to have nickel. The typical response is that they not only have to have nickel but, it has to have a few percent of nickel and not just PPM's of it. In explanation of this as I recall, I've always been told the reason that meteoritic iron always has to have Nickel is because in nature there is no way to separate the two elements. If that is true then how is it that in this case we do in fact have meteoritic metal without nickel? somehow they got separated. Unless this analysis is wrong does this not teach us that yes in fact there can and does exist meteoritic iron devoid of nickel. And therefore there not only could be Iron meteorites without nickel but,this ups the odds that there in fact are meteorites without nickel. Please see attached abstract. Back scattered images Figure 2 at the fifth page from the top of the article. It says; D. Close up of a CC Chondrule texture. Radiating unidentified minerals and Nickel free metal (met) are set up in a silica-rich matrix. http://www2.mnhn.fr/hdt205/leme/doc/2007%20Gounelle%20et%20al.%20EPSL.pdf Thanks Carl -- Carl or Debbie Esparza Meteoritemax __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list -- Dr. Jeffrey N. Grossman phone: (703) 648-6184 US Geological Survey fax: (703) 648-6383 954 National Center Reston, VA 20192, USA __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
