[meteorite-list] New Iron (Ataxite) SHRAPNEL

[Mexicodoug]

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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