[meteorite-list] Example of Lipping and direction stumper. TAKE 2

From: Jason Utas <meteoritekid_at_meteoritecentral.com>
Date: Tue, 28 Jul 2009 03:42:41 -0700
Message-ID: <93aaac890907280342y61d53cdekae1bd00c3dc62af9_at_mail.gmail.com>

Hello McCartney, All,
I would agree with John Kashuba's suggest that what you are seeing is
an effect of airflow on the trailing edge of an oriented stone. I
have seen examples of similar features on several stony meteorites,
including NWA 869, Chergach, Amgala, and most clearly on an unnamed
NWA in our collection (a good 3-400 miles away from me at the moment,
so I can't manage photos).
While I did at first toy with the idea that such lines were the result
of an oriented stone that "flipped" while in flight, the markings
simply don't look like flow lines on the leading edge of a stone; they
are more pronounced, and thinner.
While I would agree that the formation of such features seems
unlikely, I would like to point out that the "flipping over" of a
stone in ablative flight - occurring without ablation taking place
during the flip - seems even less likely - at least to me.
Regards,
Jason


On Sun, Jul 26, 2009 at 8:01 PM, Frank Cressy<fcressy at prodigy.net> wrote:
>
> Hi McCartney, Michael and all,
>
> I agree with Michael that this is the back side of an oriented meteorite. ?The lipping shows that. ?I also agree with him that it flipped during flight and that this side was once the leading side, but but neccessarily because of the flow lines. Generally the front side of an oriented meteorite has thinner crust than the rear side. ?Since we can see many chondrules through the crust, I think that the thin crust supports that it was once the leading edge.
>
> Cheers,
>
> Frank
>
> --- On Sun, 7/26/09, Michael Blood <mlblood at cox.net> wrote:
>
>
> From: Michael Blood <mlblood at cox.net>
> Subject: Re: [meteorite-list] Example of Lipping and direction stumper. TAKE 2
> To: mccartney at blackbearddata.com, "Meteorite List" <meteorite-list at meteoritecentral.com>
> Date: Sunday, July 26, 2009, 7:41 PM
>
>
> Hi McCartney,
> ? ? ? ? In the photo, first of all, if it is an oriented meteorite (and it
> seams to be) one is looking at the flat back side. One can see SOME
> Lipping on the left - especially, the upper left, but this specimen
> certainly does not display much in the way of lipping.
> ? ? ? ? In addition, some of the flow lines (very slight) on the back
> indicate that during part of the fall, the flat "back side"? of the stone
> Flipped around and was the face (or one might say it spent some
> Time tumbling as it moved through the atmosphere).
> ? ? ? ? All of these and many more phenomena will be explained with
> LOTS of photos in my book which is nearly ready to "go to print" and
> Should be available shortly.
> ? ? ? ? I have narrowed down the name and it will be, ASPECTS OF ORIENTED
> METEORITES or METEORITES SHOWING ASPECTS OF ORIENTATION.
> ? ? ? ? Best wishes, Michael
>
>
> On 7/26/09 4:00 PM, "McCartney Taylor" <mccartney at blackbearddata.com> wrote:
>
>> http://outofabluesky.com/images/stories/stoneymeteorites/allende12-7.jpg
>>
>> This is an Allende. I'm not sure I understand the orientation signs I see.
>>
>> I see a star flow line pattern which indicates this side is windward. But the
>> lipping on the NW side hints the side is leeward. So I'm a bit confused.
>>
>> Any ideas on alternate interpretations?
>>
>> -mt
>>
>>
>>
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Received on Tue 28 Jul 2009 06:42:41 AM PDT