[meteorite-list] Its official! NWA 6291 "The King ofAngrites"forsale - AD

From: GREG LINDH <geeg48_at_meteoritecentral.com>
Date: Sat, 24 Jul 2010 00:25:47 -0700
Message-ID: <BLU125-W136E1ABC20FA6149A36C0DC9A40_at_phx.gbl>

 
    Hi Sterling,
 
  On a friendly note, I must say that I look forward to your posts. While I do learn from them, much of what you say goes above my head....I'm not a scientist. I have very strong beliefs/opinions, and often these can get me into hot water on the List. But, that doesn't mean that I don't appreciate the knowledge that many of you have.
 
  With respect,
 
 
  Greg Lindh
 


----------------------------------------
> From: sterling_k_webb at sbcglobal.net
> To: photophlow at yahoo.com; meteorite-list at meteoritecentral.com
> Date: Sat, 24 Jul 2010 00:28:51 -0500
> Subject: Re: [meteorite-list] Its official! NWA 6291 "The King ofAngrites"forsale - AD
>
> Actually, I was not addressing the specific question
> of the origin of this angrite (or any angrite), but the
> more general problem of the "universal assumption
> that every sizeable body in the solar system currently
> resides at the same address where it accreted originally."
> If things move around, it complicates the picture
> considerably.
>
> I used Vesta as an example of a body that can't have
> accreted in place. If there is only enough available iron
> at 1.5 AU for Mars to accumulate a core that is only
> 8% of its volume), how could Vesta, at 2.35 AU, have
> accumulated enough iron for a core 17.5% of its
> volume, or 56% of its original, uncratered diameter?
> The Earth has a core of 17% of its volume, or just a
> hair less than Vesta. Mercury has a core that's 43%
> of its volume. Both the Earth and Mercury have
> acquired part-corers from encounters with impactors
> though.
>
> Iron is a moderately refractory element. It will be
> vaporized in the solar nebula only relatively close
> to the Sun. The temperature will drop by the square
> of the distance out in the protoplanetary disc and
> iron will soon condense into the materials from
> which grains will form, get sticky, form particles,
> accrete, etc.
>
> How you gonna get that much iron vaporized out at
> 2.35 AU? The answer to that question is the same one
> I gave before: No Way. And for the same reason.
>
> If you want to know what should accrete out there,
> you can compare Vesta to Ceres. Ceres is in essentially
> the same region as Vesta, at 2.7 AU compared to
> Vesta's 2.35. AU. Ceres seems to have no core at all,
> although Ceres is certainly large enough to have
> differentiated. Ceres likely did accrete in place from
> rock and ice, as it is the largest body in the asteroid
> zone, six times the volume of the original, uncratered
> Vesta.
>
> We can identify Lunar and Martian meteorites only
> because we have composition data gathered by humans
> and robots. That's the only reason. Without a sample
> or a set of readings from Mercury, or Venus, or anywhere,
> the means of reasonable proof are absent.
>
> When the Dawn mission gets to Vesta, we will likely
> be able to nail down the HED identification with that
> body. I quote the mission parameters: "This mission
> was designed to verify the basaltic nature of Vesta
> inferred both from its reflectance spectrum and from
> the composition of the howardite, eucrite and diogenite
> meteorites believed to have originated on Vesta."
>
> Failure to find the expected HED terrain on Vesta would
> be.... interesting. Dawn will be the first test of the entire
> effort to "reason out" parent bodies. It will provide evidence
> where they has mostly been speculation.
>
> The paper you cite (by Chambers) is a good summary
> of the problems in planetary formation theory. There
> are lots of those. I used Vesta as an example because
> it's an obvious example of the sort of thing he discusses
> in the section on "planetary embryos." Vesta would be
> at the smallest end of their size range -- not too hard
> to toss around.
>
> Until there is evidence enough to settle the question, it
> remains speculation. we've had definitions of Science and
> of Faith on the List recently. Let me add another one more:
> Speculation. Speculation is what you do while you're
> waiting for evidence, because there isn't enough evidence
> yet for proof.
>
>
> Sterling K. Webb
> -------------------------------------------------------------------------------
> ----- Original Message -----
> From: "Shawn Alan"
> To:
> Sent: Friday, July 23, 2010 10:33 PM
> Subject: [meteorite-list] Its official! NWA 6291 "The King
> ofAngrites"forsale - AD
>
>
> Hello Sterling and Listers,
>
> Sterling, thank you for your input about Angrites "might" have a
> connection with Mercury by saying Vesta quote un quote......
>
> "Vesta did not .....form where it is. No Way."
>
> Know I am kinda confused with Vesta and your connection or lack of
> connection to this topic, but I am going to make an educated guess of
> why you might have suggested Vesta in the first place.
>
> This whole topic pulls from Angrites and the possible connections they
> might have with Mercury. I am going to zero in on one meteorite, NWA
> 2999 because it seems that there has been more research done on this
> meteorite compared to other Angrites.
>
> One observation of why some scientist feel that NWA 2999 "might" be from
> Mercury is that NWA 2999 meteorite has gone through a vertical tectonics
> process, which occurs on Earth and Mercury. In addition to this vertical
> tectonic process.......
>
> Papike et al. [9]
> suggested that angrites might be samples from
> Mercury based on volatile depletion, and systematics
> of plagioclase compositions and Fe/Mn ratios in
> mafic minerals.
>
> http://www.lpi.usra.edu/meetings/lpsc2006/pdf/1344.pdf
>
> Now Sterling, is this the reason why you brought Vesta into this
> equation, because its a differentiated body and the vertical tectonic
> process might have happened on Vesta? Or its because you feel that Vesta
> some how moved from one side of the hood to the other side because of
> the iron core being too big for where Vesta is located at?
>
> Lets change the topic and focus on your statement on how you feel about
> Vesta, quote un quote ......
>
> "Vesta did not .....form where it is. No Way."
>
>
> Now this would be a perfect example to use this quote Greg Lindh.......
>
> This reminds me of a quote by Mark Twain. The quote follows:
>
> "There is something fascinating about science. One gets such wholesale
> returns of conjecture out of such a trifling investment of fact."
>
> Something to think about....
>
>
> Iron meteorites tell their own tale. These meteorites
> come from asteroids that became hot enough to melt
> and differentiate. The most plausible source of heat
> was the decay of short-lived isotopes, especially 26Al.
> Melting must have occurred while was still abundant,
> which means these asteroids took something like 2
> Myr to form [19,20]. Why did some asteroids melt
> when others did not? Presumably, different stages of
> planet and asteroid formation occurred concurrently in
> the same region of the nebula. Some objects formed
> earlier than others, and their subsequent thermal
> evolution was different as a result.
>
> http://groups.csail.mit.edu/mac/users/wisdom/extrasolar/chambers.pdf
>
> I think this pulled abstract could explain your educated guess of why
> you think Vesta had accreted somewhere else besides where it is :) My
> guess is that when differentiation occured, that with some parent body
> the process was more prevalent because there might have been an abundant
> amount of 26Al , which this short lived isotope produces alot of heat
> which would be a good environment for differentiation to take place aka
> in Vesta :) but thats my suggestion and some science to back it up :)
>
>
>
>
> Shawn Alan
>
>
>
> [meteorite-list] Its official! NWA 6291 "The King ofAngrites"for sale -
> ADSterling K. Webb sterling_k_webb at sbcglobal.net
> Thu Jul 22 17:03:44 EDT 2010
>
>
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>
> Martin, Jason, Shawn, &c.,
>
> The fly or flaw in the ointment, the paper, and the
> responses is an unspoken but apparently universal
> assumption that every sizeable body in the solar
> system currently resides at the same address where
> it accreted originally.
>
> What about a body that accretes in the 0.50 AU block,
> then moves 'way up the street and out to the 2.35 AU
> neighborhood? Like say, Vesta. Now, I'm not saying
> Vesta did that, you know, fled from the 'hood and
> moved to the suburbs... I just saying Vesta did not
> form where it is.
>
> No Way.
>
> Models that "fit" Vesta propose a iron core of about
> http://www.lpi.usra.edu/meetings/lpsc2010/pdf/2129.pdf
> 300 kilometers out of an original spherical body of
> 540 km. diameter. Such a body HAS to have accreted
> much, much closer to the Sun. I repeat, No Way.
>
> So, isotopic data that tell you where a body accreted
> MIGHT tell you everything you need to know about the
> place or it MIGHT tell you nothing of any use whatsoever.
>
> Even the old notion about the distribution of iron cores
> in the inner solar system is wrong. Decades ago, we
> assumed bigger iron cores in close, getting smoothly
> smaller as you moved out from the Sun. Then, we
> discovered that Venus' core is proportionally much
> smaller than the Earth's, and that Mars core is puny.
>
> Then, when we moved to the theory of the Moon being
> formed by a giant "impact," or graze, or embrace, all
> the models said we had two cores -- our original core
> and the core captured from the big proto-Moon. Mercury
> too shows evidence of such a collision (although no
> moon resulted).
>
> All of a sudden, Venus and Mars have "normal" cores.
> The Earth is cheating -- it's packing an extra halfcore
> in its hip pocket, and Mercury has two cores-worth of
> core. Venus and Mars that are normal respectable planets,
> and Earth and Mercury are "core-snatchers."
>
> A simple question like "what should a meteorite from
> Mercury be like?" is not a simple question. First, if
> Mercury suffered a giant impact early on, then its
> present crust (and upper mantle and maybe more)
> is derived from the impacting body. And that Big
> Whacker accreted... where? Nearby? Faraway?
> In-between?
>
> Then, there is the case of a parent body of some
> size blasted off the ORIGINAL primordial crust (and
> mantle) of Mercury by the giant impact, finding a new
> orbit, and providing enigmatic meteorites for the next
> billions of years. That original Mercurian crust could
> have been quite different from the present crust.
>
> As Jason pointed out, there were a gaggle of large
> differentiated bodies in the early system. I go with
> the "hundreds" rather than 30-40; see the work by
> SwRI that suggests 100+ of them from the inner
> solar system ended up in the Asteroid zone. The
> Zone is made up of "natives" and a horde of refugees,
> which could have accreted pretty much anywhere
> and will each have a unique formation history all
> their own.
>
> Present arguments are somewhat simple-minded.
> It's going to take centuries to sort out the life history
> of every body big enough to bother with.
>
> It's going to be fun.
>
>
> Sterling K. Webb
> --------------------------------------------------------------------------------
> ----- Original Message -----
> From: "Martin Altmann"
> To:
> Sent: Thursday, July 22, 2010 6:00 AM
> Subject: Re: [meteorite-list] Its official! NWA 6291 "The King
> ofAngrites"for sale - AD
>
>
> Huh, I found even a paper, which postulates, that the HEDs are from
> Mercury
> and the angrites from Venus....
>
> http://www.lpi.usra.edu/meetings/otp2004/pdf/3012.pdf
>
>
>
> ;-)
> Martin
>
>
>
> -----Urspr?ngliche Nachricht-----
> Von: meteorite-list-bounces at meteoritecentral.com
> [mailto:meteorite-list-bounces at meteoritecentral.com] Im Auftrag von
> Jason
> Utas
> Gesendet: Donnerstag, 22. Juli 2010 11:27
> An: Shawn Alan; Meteorite-list; Adam Hupe
> Betreff: Re: [meteorite-list] Its official! NWA 6291 "The King of
> Angrites"for sale - AD
>
> Shawn,
> Well-said -
> But I can't emphasize enough the fact that such large bodies existed
> in large numbers in the early solar system. That much is obvious from
> the large numbers of ungrouped (and grouped) differentiated
> achondrites that we have in our collections here on earth, as well as
> from all various types of iron meteorites, which represent the cores
> of diffeentiated planetismals. All in all, we have meteorites that
> suggest well over 30-40 such bodies in the early solar system, and
> computer-run models in some cases suggest hundreds of such bodies.
>
> http://www.ucmp.berkeley.edu/education/events/cowen1d.html
>
> http://en.wikipedia.org/wiki/Formation_and_evolution_of_the_Solar_System#For
> mation_of_planets
>
> Note that wikipedia suggests 50-100 such bodies. I wouldn't usually
> reference wikipedia for something like this, but see references 35-36
> for the article - that's actually a decent estimate that's been backed
> up by some serious work done by experts -- it's not just a crap
> wikipedia reference.
>
> So, angrites may be from Mercury. If we say that, regardless of their
> composition and history, they just needed to be from a large
> planetismal capable of some metamorphic activity, then we've got a
> 1/50 to 1/100 chance that angrites are, in fact, from Mercury.
>
> The trouble is that their chemistry and age suggest that they're not
> from Mercury.
>
> I agree. They *might* be from Mercury. And yes, some smart people
> have said that they *might* be from Mercury.
> But it seems to me that this article is being deemed credible because
> of its authors, and not because of what it actually says.
>
>
>>I do not refute Melinda Hutson's article that was never peer reviewed
>
>>and
>
> contains several errors according to the classifying scientists. I
> asked
> scientists about the article and they stated, it is obvious that she
> didn't
> read
> the original peer reviewed abstract carefully, even mistaking the type
> of
> petrology that was discussed using formulas that simply do not apply to
> the
> texture NWA 2999 exhibits.
>
> I'd like to know what these errors were, and how the error might have
> affected her conclusions. Perhaps Adam or someone else would be
> willing to explain her errors and how they suggest that angrites are
> actually from Mercury.
>
> Seems like this is the perfect sort of topic for the list...
>
> Regards,
> Jason
>
>
>
>
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Received on Sat 24 Jul 2010 03:25:47 AM PDT