Largest Crater in the Great Sahara Discovered by Boston University Scientists
baa...@earthlink.net
For Release Upon Receipt - March 3, 2006
Contact: Kira Edler, 617-358-1240, ked...@bu.edu
LARGEST CRATER IN THE GREAT SAHARA DISCOVERED BY BOSTON UNIVERSITY
SCIENTISTS
Researchers from BU's Center for Remote Sensing locate crater using
detailed satellite data
(Boston) - Researchers from Boston University have discovered the
remnants of the largest crater of the Great Sahara of North Africa,
which may have been formed by a meteorite impact tens of millions of
years ago. Dr. Farouk El-Baz made the discovery while studying
satellite
images of the Western Desert of Egypt with his colleague, Dr. Eman
Ghoneim, at BU's Center for Remote Sensing.
The double-ringed crater - which has an outer rim surrounding an inner
ring - is approximately 31 kilometers in diameter. Prior to the latest
finding, the Sahara's biggest known crater, in Chad, measured just over
12 kilometers. According to El-Baz, the Center's director, the crater's
vast area suggests the location may have been hit by a meteorite the
entire size of the famous Meteor (Barringer) Crater in Arizona which is
1.2 kilometers wide.
El-Baz named his find "Kebira," which means "large" in Arabic and also
relates to the crater's physical location on the northern tip of the
Gilf Kebir region in southwestern Egypt. The reason why a crater this
big had never been found before is something the scientists are
speculating.
"Kebira may have escaped recognition because it is so large - bigger
than the area of 125 football fields, or the total expanse of the Cairo
urban region from its airport in the northeast to the Pyramids of Giza
in the southwest," said Dr. El-Baz. "Also, the search for craters
typically concentrates on small features, especially those that can be
identified on the ground. The advantage of a view from space is that it
allows us to see regional patterns and the big picture."
The researchers also found evidence that Kebira suffered significant
water and wind erosion which may have helped keep its features
unrecognizable to others. "The courses of two ancient rivers run
through
it from the east and west," added Ghoneim.
The terrain in which the crater resides is composed of 100 million
year-old sandstone - the same material that lies under much of the
eastern Sahara. The researchers hope that field investigations and
samples of the host rock will help in determining the exact age of the
crater and its surroundings.
Kebira's shape is reminiscent of the many double-ringed craters on the
Moon, which Dr. El-Baz remembers from his years of work with the Apollo
program. Because of this, he believes the crater will figure
prominently
in future research in comparative planetology. And, since its shape
points to an origin of extraterrestrial impact, it will likely prove to
be the event responsible for the extensive field of "Desert Glass" -
yellow-green silica glass fragments found on the desert surface between
the giant dunes of the Great Sand Sea in southwestern Egypt.
Dr. El-Baz is research professor and Director of the Center for Remote
Sensing at Boston University. He is a renowned geologist who over the
past 30 years has conducted studies in all the major deserts of the
world. He is a member of the U.S. National Academy of Engineering and a
Fellow of the American Association for the Advancement of Sciences and
the Geological Society of America. The latter established the "Farouk
El-Baz Award for Desert Research" to reward excellence in arid land
studies.
Dr. Eman Ghoneim is a research associte at the Center for Remote
Sensing. She is an expert in hydrological modeling and now conducts
research on arid land geomorphology with emphasis on groundwater
concentration under the direction of Dr. El-Baz.
The Boston University Center for Remote Sensing is a research facility
that was established in 1986. Researchers at the Center apply
techniques
of remote sensing and geographic information systems (GIS) to research
in the fields of archaeology, geography and geology. In 1997, the
Center
was recognized by NASA as a "Center of Excellence in Remote Sensing."
Founded in 1839, Boston University is an internationally recognized
institution of higher education and research. With more than 30,000
students, it is the fourth largest independent university in the United
States. BU contains 17 colleges and schools along with a number of
multi-disciplinary centers and institutes, which are central to the
school's research and teaching mission.
- 30 -
Note to editors: Images available online at
http://www.bu.edu/remotesensing/News/kebira/index.html
Unknown
If confirmed, it will constitutes the 173th confirmed meteorite crater (on
about 500 knewn)
See the list on MIAC website or an update one with stuctures in suspend at
http://www.astrosurf.org/lombry/impactlistecrateres2.htm
Thierry
<baa...@earthlink.net> wrote in message
news:1141425427.3...@v46g2000cwv.googlegroups.com...
wa2ise
high ground and mountains in the middle, and a lot of missing rim.
Unless they can find (or have found) evidence of shocked rock and such
that is only found in impact craters, I wouldn't think that that's a
crater.
Unknown
"wa2ise" <wa2...@ix.netcom.com> wrote in message
news:1141520582....@v46g2000cwv.googlegroups.com...
For sure that usually craters are circular with a central peak, like school
drawings...
But a subjective feeling has no value in this matter and no geologist could
base his work on such data...
High ranges exists in other craters (gosse bluff, Gilf Kebir, etc).
See something similar to Kebila in Lybia
http://www.astrosurf.org/lombry/Sciences/impact-oasis.jpg
You cannot make your opinion from such ideas. Many geologic phenomenon can
produce a central mountain and even concentric ranges, etc, without speaking
about erosion, a secondary impact, etc. See Richāt which is now considered
as *not* an impact crater, here evidences seems to proof the contrary...
See images attached to each crater in the next link and you will understand
that sometimes a crater can be almost anything... As you say, an untrained
eye cannot see themn mainly whehn they are located in ranges but all will
depend on the discovery or not of various clues, beginning by shock cones.
http://www.astrosurf.org/lombry/impactlistecrateres2.htm
Thierry
>
George
"wa2ise" <wa2...@ix.netcom.com> wrote in message
news:1141520582....@v46g2000cwv.googlegroups.com...
Old, eroded craters tend to look that way. "Yellow-green silica glass
fragments found on the desert surface between the giant dunes of the Great
Sand Sea in southwestern Egypt" may fit the bill.
George
Alan Johnson
The press release doesn't offer an enormous amount of information - I
assume more will be forthcoming. I consider it to be just as
unscientific to dismiss it out of hand as it would be to say I've found
a piece of glass, I must be in an impact crater. Especially if all
you've got is an untrained eye!
Regards
Jonathan Silverlight
<afjo...@geotrans-online.de> writes
Right now it looks like the argument that part of Hudson Bay is an
impact crater on the basis of its circular shape, and as this page notes
there's a lot of "missing evidence" that needs to be found.
<http://www.smplanet.com/science/astropuzzle.html>
Presumably the next step is to actually go and find it!
--
NASA Not About Science Anymore
Alan Johnson
That's not a new hypothesis. As stated above, I wouldn't dismiss the
idea out of hand. I *suppose* one of the prime indicators of a possible
bolide origin for a given structure, failing a less obvious explanation,
is the circular shape. But yes, let's see the evidence on the table.
That's the name of the game.
Regards
Aidan Karley
> I consider it to be just as
> unscientific to dismiss it out of hand as it would be to say I've found
> a piece of glass, I must be in an impact crater. Especially if all
> you've got is an untrained eye!
>
because they require a *very* high rate of change of stress to develop.
--
Aidan Karley FGS
Aberdeen, Scotland,
Location: 57°10'11" N, 02°08'43" W (sub-tropical Aberdeen), 0.021233
Sir Jean-Paul Turcaud
pipes !
Indeed following the True Geology teaching, diamonds pipes are very closely
related to meteorite impacts since indeed produced by such ! Diamonds
pipes in ZA Kimberley and Western Australia Kimberley ( Argyle ) as well as
due to such impact.
NB
En ce qui concerne Richât, il s'agit d'une structure diamantifère qui n'a
pas pu emerger pour des raisons que la True Geology demontre facilement.
As far as Richât this is a typical type of diamond pipe which has not had
enough pep to come over to the surface. I assume the Peridotite could be as
little as 500 m under the top of the structure.
I suppose there should be a good half dozen diamond pipes in the vicinity of
Kebira, then which of course True Geology techniques would take very little
time to find !
In a coming post going to be called THE ROOT OF DIAMONDS I will demonstrate
how diamonds instead of being rare are in fact representing millions & of
tons ( Where ? ) and are available in subsea deposits by the
thousands of tons
With best regards
--
Sir Jean-Paul Turcaud
Australia Mining Pioneer
Founder of the True Geology
Exploration Geologist & Offshore Consultant
Mobile +33 650 171 464
mining_pioneer/at/yahoo.com
http://www.tnet.com.au/~warrigal/grule.html
http://users.indigo.net.au/don/tel/index.html
~~ Ignorance Is The Cosmic Sin, The One Never Forgiven ~~
"Aidan Karley" <doIlookDAFT...@validEMAILaddressTOa.NEWS.group> a
écrit dans le message de news:
VA.00000ce...@validemailaddresstoa.news.group...
Saul Levy
None? Figures. Your True Geology is a miserably-failed bunch of
shit!
Saul Levy
Unknown
"Alan Johnson" <afjo...@geotrans-online.de> wrote in message
news:due9mv$3g9$00$1...@news.t-online.com...
Must be an impact ?... if you find cone shocks and breccia, maybe.
Here is a google local image
http://maps.google.com/maps?f=q&hl=en&q=N24%C2%B040%27,+E24%C2%B0+58%27&t=h&ll=24.680401,24.965572&spn=0.567762,1.2854&t=h
A+
Thierry
http://www.astrosurf.org/lombry
>
> Regards
Jonathan Silverlight
That's more convincing than the processed image on the Boston University
site - you shouldn't need a dashed line to outline the crater :-)
I notice there are also circular structures to the left and below the
one Farouk El-Baz is interested in.
pete
<jsilve...@spam.merseia.fsnet.co.uk.invalid> sez:
` In message <440c47d8$1...@news.vo.lu>, Thierry <?@?.?.invalid> writes
The one to the left is already listed in at the site Thierry pointed
to, as "Oasis, Libya". It's at 24° 35' N, 24° 24' E. There's also one
listed directly north at the end of the rock island in the midst of
the sea of dunes, as it were, called "B.P. Structure", at 25° 19' N,
24° 20' E. Quite a collection. Now is it coincidental, a result of
ease of identification due to lack of overburden and erosion (ie
typical of the frequency of cratering across the globe if we could
but see it), or are they associated as a simultaneous cluster hit?
--
==========================================================================
vincent@triumf[munge].ca Pete Vincent
Disclaimer: all I know I learned from reading Usenet.