[meteorite-list] Franconia AREA (was, Re: ...terminology...)

From: Jim Wooddell <jimwooddell_at_meteoritecentral.com>
Date: Wed, 1 May 2013 19:12:36 -0700
Message-ID: <CAH_zgwHeAaPHy2Hn677ghrQx=wOTDAm1ckSXhWjfrtc5brVyiw_at_mail.gmail.com>

 Mike and all,

I have to agree with the visual pairing was completely misleading.
That ought to PO 90% of the hunters out there. I never did have that
skill and I know some fellows are very exceptional at guessing what
the rock is.
Here is a picture of a fairly good sized Franconia area recovery. I'd
like to ask how many classifications could come out of this rock
looking at the clasts which become vary apparent in the larger rocks.
And, you can see signs, at the boundary of those clasts, where
separation is occurring. So, some of the fragment are one type of
clast and some are other types of clasts. They look different in the
rock and they look different as individual fragments. Note the color
differences and not the number of chondrules in different area.
I am in no way an expert, but if I find any kind of fragment of a
meteorite and then later find another, when I cut them and they look
different, I am going to think they are different and I might be
right!

Jim


On Wed, May 1, 2013 at 2:09 PM, Michael Mulgrew <mikestang at gmail.com> wrote:
> List,
>
> One more question regarding the latest Franconia paper, M. Hutson et
> al., 2013, regarding the sample sized used in that study vs. their
> concluded number of falls for the area: They only looked at 14 rocks,
> concluding that 7 were separate falls. If they looked at 50 rocks,
> would they have found 25 falls? Why did they select only 14 rocks,
> was it a matter of how much research they could fund? I'd hope the
> samples were not selected specifically for their appearance, as they
> stated in the paper that visual pairing based on the exterior of the
> stones was completely misleading.
>
> They incorrectly reported that the 14 stones in their study make up
> 3.7% of the total finds for the area, 380. We all know this number is
> much higher, by a factor of 20 or more probably. For example, I know of
> one hunter who made more than 600 finds in a single year. A similar
> disconnect exists with their statement regarding the % representation of
> total mass of all finds. I'm not sure how they can come to such a
> definitive fall count with such a miniscule sampling of finds from the
> area.
>
> Ok, two questions: Does anyone know why the irons (H-metal) from the
> area were ignored in this study? Surely they are directly related to
> these chondritic falls, and as Yucca 015
> (http://www.lpi.usra.edu/meteor/metbull.php?code=57175) shows us,
> there are multiple unique H-metals out there as well.
>
> Back to winning the lottery to get all this sorted out!
> Michael in so. Cal.
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-- 
Jim Wooddell
jimwooddell at gmail.com
928-247-2675

Received on Wed 01 May 2013 10:12:36 PM PDT