[meteorite-list] New Iron (Ataxite) SHRAPNEL

From: Mexicodoug <mexicodoug_at_meteoritecentral.com>
Date: Tue, 22 Jun 2010 13:04:49 -0400
Message-ID: <8CCE0441CEA650F-9DC-529B_at_webmail-m092.sysops.aol.com>

Hi Svend, List,

"Zooming out the sat-image, one notes that the general wind direction
in the area
is north by northeast to south to southwest. Thus, any Aeolian
deflation or wind
shaped sedimentation pattern around the crater would have to be
oriented along
this axis. This appears not to be case. Instead we see a radial pattern
with the
crater as its center."

Svend has described poetry in motion; I am going to save his
description for reruns with a cup of coffee and savour the detailed
analysis, perhaps when life is at a kind moment and I am out in the
desert observing the night sky and inventing my own constellations for
family members.

The impact rays are probably already covered quite well, but if it is
not clear, let me try to add this:

We have a central source of material and under Richard's hypothesis,
wind blowing down points on the rim to form these "rays". We look at
the rays and the first thing we notice is that they are as quite well
defined. Svend's comments about the character of the prevailing wind
direction, pavement and bedrock aside, let's try the strategy of proof
by contradiction strictly under Richard's hypothesis:

Suppose this is a sandy or powdery place where the wind can blow out
spokes from the sand source(hole, crater, pit, whatever). Looking at
the rays from all directions we are forced to reason that the wind must
be blowing from all those directions or else we wouldn't have a hub and
spoke design around the crater.

But ... if the wind is blowing sand and powder spokes from all
directions, why would the spokes be linear, nearly as well formed
distally as near the crater? Because wind from all the directions of
the compass would cause a scattering proportional to the distance from
the crater, perhaps curves if it was a windstorm from another
direction, and not a sharp delineation towards the ends of the rays
like a bicycle wheel. The absence of this is a contradiction ... the
backbones of the rays are too straight and well defined to support
Richard's idea. A much simpler explanation is that someone painted them
on a something solid ground - who better than Mother nature responding
to the impact?

Kindest wishes Svend, and Richard, thanks
Doug



-----Original Message-----
From: info at niger-meteorite-recon.de <info at niger-meteorite-recon.de>
To: meteorite-list at meteoritecentral.com
Sent: Tue, Jun 22, 2010 3:26 am
Subject: Re: [meteorite-list] New Iron (Ataxite) SHRAPNEL


Dear Richard, Doug, others,
?
while the crater floor indeed seems to be covered by wind borne sand
deposits we
should take note that the surrounding surfaces are composed of coarser
material,
most probably some sort of desert pavement, which in turn covers a
coarser
weathering layer of the underlying bedrock (my guess is Eocene
limestone). Wind
borne sand is present leeward of outcrops and in the gullies, but on the
deflation plains its presence is limited to the interspaces of the
small pebbles
forming the top surface.
?
Although to a lesser extent than the sandstone bedrock of the Uwaynat
or the
Gilf Kebir, the exposed Eocene limestone rock of the nearby outcrops has
developed darkening due to the forming of desert varnish. This is a
practicable
indicator for relative surface ages on sat images for the general area.
The
gullies of the drainage system show brighter colors, due to their
relatively
young Holocene formation. The deflation areas with undisturbed desert
pavements
show an intermediate darkening. The dark grey hue of the coating on the
desert
pavement can be seen best east of the gully running north to south
approx. 120
meters east of the crater.
?
The ejecta rays, and I am convinced this is what we are looking at
here, are of
a brighter color, indicating less darkening of the material by desert
varnish
and a more recent formation compared to the deflation plain on top of
which it
came to rest. The borders of the ejecta blanket are actually quite
crisp,
particularly east of the crater where one can see the eastern ejecta
ray cutting
across the gullie and into the undisturbed desert pavement.
?
When zooming into the image, it also becomes obvious that the ejecta
material,
at least in the ray pointing to the southeast, includes coarser bedrock
material, very much like the material which can be seen in the crater
rim. The
bright patches of ejecta material in the north and northeast of the
crater are
most probably composed of larger fragments too. No silt or sand deposit
would
last very long on top of these plains since the intense winds in the
area blow
almost 300 days a year (and from the same direction).
?
To get a picture of the intense forces shaping this incredible
landscape one may
inspect the sharp-crested Seif-dunes (after the Arabic word for
?sword?) which
formed parallel to the prevailing wind direction in the lee of an
outcrop ~ 3 km
to the northwest of the crater).
?
Zooming out the sat-image, one notes that the general wind direction in
the area
is north by northeast to south to southwest. Thus, any Aeolian
deflation or wind
shaped sedimentation pattern around the crater would have to be
oriented along
this axis. This appears not to be case. Instead we see a radial pattern
with the
crater as its center.
?
Once again the link to the crater site to compare:
?
http://maps.google.de/maps?f=q&source=s_q&hl=de&geocode=&q=26%C2%B0+05%27+16%22+E,+22%C2%B0+01%27+6%22+N&sll=50.234524,12.885482&sspn=0.007974,0.01929&ie=UTF8&ll=22.018379,26.087661&spn=0.001445,0.002411&t=h&z=19
?
?
Cheers,
Svend

Richard Kowalski <damoclid at yahoo.com> hat am 21. Juni 2010 um 22:37
geschrieben:

> Mike and Doug. Cool beans!
>
> Doug, I'd be hesitant to call those rays, especially considering how
full of
> sand the crater is, any rays would probably have been covered or
destroyed
> long ago. (Rays are somewhat fragile)
>
> I zoomed into the crater in Google Earth with a horizontal view,
exaggerating
> the relief to the maximum setting and it appears the crater is on a
gentle
> slope, higher to the north east and lower to the south and west. The
rim is
> very low, at least as displayed in GE.
>
> I'd guess the apparent rays are just due to windblown sand and dust
shaped by
> the profile of the rim itself.
>
> Are there any photos from ground at the site available?
> Since it is a disputed zone, I doubt any higher resolution aerial
images will
> become available any time soon, but someone may want to custom order a
> satellite image of the area.
>
> --
> Richard Kowalski
> Full Moon Photography
> IMCA #1081
>
>
> --- On Sun, 6/20/10, Mexicodoug <mexicodoug at aim.com> wrote:
>
> > The crater itself is relatively small and a
> > 10 minute walk from the Sudan and not too far from Libya,
> > for those who would enjoy a safer GooglEarth trek for the
> > the impact crater can look here in the Gilf Kebir zone
> > (22?01'6"N, 26?05'16"E). This is a real crater with real
> > meteoritic shrapnel, not borderline, even look at the rays
> > which are still there from the impact !
>
>
>
>? ? ? ?
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Received on Tue 22 Jun 2010 01:04:49 PM PDT