Libya's Kebira Crater
A huge crater in the
Sahara desert, said to be the largest one ever found in the
region, and dwarfing Arizona's "Meteor Crater", poses new
questions for geologists. Is the crater related to the
origins of the mysterious "desert glass" in the region?
Scientists suggest that a meteorite impact millions of years
ago is the cause of the giant crater imaged above. Recently
discovered in satellite images of the area, the crater lies
in Egypt's western desert. It is some 19 miles
(31kilometers) wide and is said to be the impact site of a
meteoric intruder perhaps three-fourths of a mile (1.2
kilometers) in diameter. The crater itself is more than 25
times the size of Arizona's famous Meteor Crater. But over
time, erosion by wind and water largely obscured the ancient
One intriguing aspect of the discovery is its close
association with a mysterious field of yellow-green glass,
broken into large chunks, littering the dunes in the Great
Sand Sea of southwestern Egypt.
The first report
of the yellow-green “desert glass” came from Patrick Clayton
in 1932, following his excursion through the Saad Plateau
near the Kebira Crater site. At the time, the origin of the
glass was unknown: There was no evidence of geological
forces that could have melted the silica sand into glass.
With Kebira’s discovery, a hypothetical source for the glass
is now available.
Geologists speculate that the glass originated as ejecta
from the Kebira impact. It is thought that the meteor strike
imparted so much energy to the surrounding silica sand that
it was melted and then explosively hurled outward,
solidifying and fracturing into shards, as depicted
Although the glass is most likely a result of Kebira, the
method by which it was created is open to question.
1. The glass is too pure – some of the purest natural silica
glass ever found. If the glass shards are tektites (melted
slag from volcanoes or meteor impacts), they should include
the presence of other minerals.
2. The glass does exhibit small internal bubbles that
include other elements. One of those elements is iridium,
the presence of which indicates an extra-terrestrial origin,
according to prevailing theories (see Alvarez, Luis W., et
al. "Extraterrestrial Cause for the Cretaceous-Tertiary
Extinction: Experimental Results and Theoretical
Interpretation." Science 208 (1980) 1095-1108). However, the
glass reveals no evidence of other minerals found in the
region, such as halite and alumina.
3. Another area where this type of glass may be found is
If the explosion of a solid object, like a meteor, did not
form the glass, then there remains one other method
available—an enormous electrical discharge. The glass
shards, then, are the remains of large
Fulgurites are created when bolts of lightning strike
refractory minerals in the earth, instantaneously smelting
the minerals into other forms, such as cristobalite. The
yellow-green glass does, in fact, contain cristobalite
inclusions, along with the iridium and other platinum family
If one grants the power of a lightning bolt large enough to
form an impact site some 19 miles in diameter, then
additional possibilities must also be considered. Electrical
theorists have long claimed that highly energetic electric
discharge transmutes elements—a process that is going on all
the time on the surface of stars, they contend. The same
thing is implied on Jupiter's moon Io, where electric
discharge appears to be continuously transmuting oxygen from
water ice into sulfur. (The association of energetic
lightning strikes with a "sulfurous stench" is much more
than an old wives' tale, the electrical theorists say).
Is the Kebira site the scar of a cosmic thunderbolt? If so,
new directions of investigation will be essential.
Please visit our
The Electric Sky
and The Electric Universe