Alan
----- Original Message -----
From: <[email protected]>
To: "Jeff Grossman" <[email protected]>; "meteoritelist"
<[email protected]>
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 <[email protected]> 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, [email protected] 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
>> > ______________________________________________
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>> >
>> >
>>
>>
>> --
>> Dr. Jeffrey N. Grossman phone: (703) 648-6184
>> US Geological Survey fax: (703) 648-6383
>> 954 National Center
>> Reston, VA 20192, USA
>>
>>
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