[meteorite-list] FW: Rocks from Space Picture of the Day -May 8, 2010

From: cdtucson at cox.net <*cdtucson_at_meteoritecentral.com*> Date: Sun, 9 May 2010 12:35:13 -0400 Message-ID: <20100509123513.UEJJH.313213.imail_at_fed1rmwml33> · cdtucson_at_meteoritecentral.com

--
Carl or Debbie Esparza
Meteoritemax
---- thetoprok at aol.com wrote: 
> Hi Rob, List,
> 
> I'd like to address a couple of points Rob made. I have great repect
> for you Rob, you are one smart dude, no doubts here!
> 
> No disrespect intended to anyone out there, we all have opinions and
> that's what makes it all so fun!  (Sorry to Phil and Warren for my
> "full of it" comment last night, I was having fun at your expense and
> should not have
> made the comment, nothing personal.)
> 
> First, I don't believe anyone here thinks of the Franconia irons as an
> independent fall. It is widely known and understood that these are
> spalled out of the H chondrite. If my memory serves me correctly there
> were a few of you real smart guys out there that were adament opponents
> of a meteoritic origin at all concerning these tiny irons. A bunch of
> us that were in the field finding these little oriented beauties
> couldn't understand this position and I was truly starting to doubt
> some of the science/scientists. I'm glad it was straightened out and
> the truth acknowledged. I don't know if I agree with them getting their
> own classification but something needed to be done to acknowledge the
> unusual circumstances and unlikely event that created these. That being
> said, let's look closely at the irons, they may tell the whole story if
> we
> can learn to read them.
> 
> Rob says they didn't have the opportunity to experience "high altitude,
> high velocity ablation." I've posted some more pictures to my
> photobucket site. Though they are not the best pic's they do
> demonstrate the fact that at least some of these experienced some
> serious ablation, from flow lines to roll over lipping, bullet shapes
> and BB's. That in my
> opinion constitutes high altitude, high velocity ablation. These shapes
> did not occur some time after the stone was on the ground and the metal
> weathered out, nor did the shapes occur during dark flight, no way no
> how.
> 
> As far as weathering away over the long period of time since the fall,
> I have no answer for that. However, it is a fact that many of the irons
> that have been found are smaller than .1 gram. I've found them myself
> and I've looked at other peoples finds that are very tiny. Somehow they
> are not weathering into oblivion. Perhaps this is another aspect of
> these irons that is not yet understood. Some are more weathered than
> others. They range in color from gun barrel blue to orange rust, some
> are black, others are brown, with different degrees of weathering
> apparent.
> 
> I believe it's important to know the true answer because if it is a 
> meteorite it should shed light on the impact pits on Sikhote Alin and 
> other irons. Some people think that impurities popped out of the iron, 
> or in the case of Franconia, that chondrules popped out, while others 
> see a splash as if something impacted it. My little enigma may answer 
> that question if it is proven to be of extraterrestrial origin. That 
> would be a contribution to the science.
> 
> If the RFSPOD object is a meteorite I think it is imperative that that
> be known. I feel an obligation to put it to the test and I'm close to
> having a SEM reading. I'll certainly inform the list when the results
> come in.
> 
> Whatever the result is this has been a positive thread that inspires
> people to think and have constructive conversation and debate, what
> else could you ask for?
> 
> http://s934.photobucket.com/albums/ad190/alienrockfarm/
> 
> Best Regards to All
> Larry
> 
> 
> -----Original Message-----
> From: Rob Matson <mojave_meteorites at cox.net>
> To: meteorite-list <meteorite-list at meteoritecentral.com>
> Sent: Sun, May 9, 2010 3:19 am
> Subject: Re: [meteorite-list] FW: Rocks from Space Picture of the Day
> -May 8, 2010
> 
> Hi All,
> 
> Short opinion:  manmade.
> 
> Reasoning:  the inability to produce such a form purely through
> atmospheric ablation. Just to remind everyone, all of the
> so-called Franconia irons are nothing more than chondritic
> iron that has separated from an H-chondrite fall -- either
> during flight, or by terrestrial weathering processes on the
> ground. Thus it has always bothered me that these irons were
> given a separate meteorite name from the ubiquitous H-chondrites
> at Franconia from which they derive. If my information is
> outdated on this subject, someone please let me know. But many
> (most?) of the people I know who have hunted Franconia and
> found these irons do not pretend that they are from a separate
> iron fall -- they all accept that the iron nuggets were
> spalled from an H-chondrite.
> 
> So, getting back to Larry's unusual, tiny iron find. If this
> iron did not start at the top of the atmospere as a very tiny
> piece of iron, there would be no way to ablate it, let alone
> punch a hole through it. Since the Franconia irons were once
> part of a massive chondritic meteoroid, there was no opportunity
> for these irons to experience independent, high altitude, high
> velocity ablation. Their ablation history wouldn't have started
> until the main H-chondrite body had fragmented on a gigantic
> scale (e.g. terminal burst), which of course would have
> occurred at comparatively low altitude.
> 
> On a final note, the H-chondrite fall at Franconia was not
> a recent one. While this part of NW Arizona receives little
> seasonal rainfall, I don't imagine that a 0.1-gram piece of
> iron could survive more than a century. But a manmade piece
> of iron, dropped there in the last 50 years, might possibly
> survive terrestrial weathering.
> 
> I would love nothing more than for Larry's find to have an
> extraterrestrial origin; but the physics and history of finds
> at Franconia argue strongly against it.
> 
> Best wishes,
> Rob
> 
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