[BR-Crater] Fwd: Meteorite crater mystery/trip

[Ian Kluft]

On Wed, Jan 09, 2008 at 11:41:02PM -0800, Robert Verish wrote:
> Another Forward from the Meteorite-List:
> 
> ----------------------------------------------
> [meteorite-list] Meteorite crater mystery/trip
> 
> ensoramanda ensoramanda at ntlworld.com
> Wed Jan 9 21:39:15 EST 2008
> 
> Can anyone help to identify the structure I
> photographed in the link at the end of this post?
>[...] 
> Anyway...back to the original request. On the Dec 1st
> flight out to Oz we passed over northern China...a
> wonderful view of the mountains and deserts from 35000
> ft. Again I took far too many photographs out of the
> plane window...but caught this shot of a very
> interesting structure,
> which looks incredibly like a huge impact crater or
> astobleme to me. I have not been able to confirm what
> it is and wondered if anyone else on the list had ever
> seen it or could identify it? Been trying google earth
> but no luck yet. The scale can be judged to some
> extent by the small settlement nearer the foreground.
> 
> Here's the link...
> 
> http://i117.photobucket.com/albums/o43/LaburnumStudio/Craters/Crater-.jpg

That's a nice photo!

I think a candidate may be the Bigach crater in Kazakhstan.
   http://www.unb.ca/passc/ImpactDatabase/images/bigach.htm
   http://en.wikipedia.org/wiki/Bigach_crater

The first thing I did was try to narrow down what part of the world to
look at.  (That sounds like a good idea, right? :-)  Mr Ensor signed his
message with UK - so I used the Great Circle Mapper site to plot the path
between London and Hong Kong.  (It won't be exactly along the great circle.
But it'd be near it if he was on a non-stop flight.)
   http://gc.kls2.com/cgi-bin/gc?PATH=lhr-hkg&PATH-UNITS=mi&SPEED-UNITS=kts&RANGE-STYLE=best

Since it's such a well-defined circular shape, I first looked for where
confirmed craters are near the route.  The UNB/PASSC database has a string
of confirmed craters in Kazakhstan but nothing near the route in China.
I also looked through the IFSG Suspected Earth Impact Sites database.

Looking at them on Google Earth is frustrating to try to match the terrain
and patchwork photos.  Bigach crater seems to match the terrain... sort of.
The colors of the photos that Google patches together aren't even consistent
with each other.  And who knows what time of year they were made?

The colors are so different that I rejected it before coming back to it.
Turning on terrain exaggeration on Google Earth, some of the rim features
look similar.  The stream making the 90-degree turn and the location of
the town of Bigach appear to match the airliner photo.

Here's a Google Earth KMZ file trying to match the view in the airliner photo:
   http://ian.kluft.com/tmp/Bigach_crater.kmz

And a JPEG of the Google Earth view:
   http://ian.kluft.com/tmp/Bigach_crater.jpg