[meteorite-list] "Ancient Atomic Bombs" (Libyan Desert Glass)

[oxytropidoceras at cox.net]

In "Ancient Atomic Bombs" at,
http://six.pairlist.net/pipermail/meteorite-list/2009-October/057786.html
Michael Groetz asked:

"Sand dunes in the Egyptian desert. What 
phenomenon could be capable of raising 
the temperature of desert sand to at least 
3,300 degrees Fahrenheit, casting it into 
great sheets of solid yellow-green glass? 

The article in question is "Ancient Atomic Bombs" by
Leonardo Vintini, Epoch Times, Oct. 31, 2009,

http://www.theepochtimes.com/n2/content/view/24575/

Contrary to the claims made in the article, an 
extraterrestrial impact of some sort is capable of 
explaining the Libyan Desert Glass as this material 
is commonly called. Many of the objections are made in 
this article are based upon a mixture of misinformation 
and falsehoods presented in this article; research 
either ignored or overlooked by in this article; and 
over lack of understanding of what is currently known 
about Libyan Desert Glass.

First, the article dismisses the involvement of an 
extraterrestrial impact because of the "absence of 
accompanying craters in the desert." The absence of an 
impact crater in the vicinity of the Libyan Desert 
Glass is not problem because an aerial burst, which 
would have not left a crater, could have melted the 
ground's surface to create it. Various researchers 
have used computer models to demonstrate that this 
physically possible. they include:

Boslough, M. B. E., and D.A. Crawford, 2008, Low-
altitude airbursts and the impact threat. International 
Journal of Impact Engineering. vol. 35, no. 12, 
pp. 1441-1448.

Svetsov V. V. and Wasson J. T. 2007. Melting of Soil 
Rich in Quartz by Radiation from Aerial Bursts - A 
Possible Cause of Formation of Libyan Desert Glass 
and Layered Tektites. Abstracts of the Lunar and 
Planetary Science Conference. 38th, Abstract no. 1499. 

Wasson J. T., 2003., Large Aerial Bursts: An Important 
Class of Terrestrial Accretionary Events. Astrobiology. 
vol. 3, no. 1, pp. 163-179. 	

In addition, the Libyan Desert Glass (LDG) occurs as 
surface lag composed of loose cobbles, pebbles, and 
granules. Since the LDG is found in place, it allows for 
a number of explanations of how the material was 
created. These include the LDG is what remains of 
former melt pool of a crater that has since been 
eroded away, leaving a lag of fragmented glass, is 
what remains of a solid sheet of glass created by an 
aerial burst that has been completely fragmented by 
subsequent erosion; and is what remains of impactites 
created elsewhere outside its current distribution 
and subsequently eroded from its original source, and 
transported to where it is now found. There are a 
number of pros and cons to these and other ideas 
about how LDG formed, which are too lengthy to discuss 
in any detail in this post.

The LDG is similar to Mong Nong-type tektites, which 
with other Australasian tektites are of impact origin 
and lack a known impact crater. ("impact origin" includes 
both the terrestrial impact origin and impact of lunar 
material hypotheses.) Thus, the LDG is not the only 
glassy impactite that lacks a known crater.

Pertinent reference:

Ramirez-Cardona, M., El-Barkooky, A. Hamdan, M. Flores-
Castro, K., Jimenez-Martinez, N. I., and Mendoza-
Espinosa, M., 2008, On the Libyan Desert Silica Glass 
(LDSG) transport model from a hypothetical impact 
structure. PIS-01 General contributions to impact 
structures, International Geological Congress Oslo 
2008, Oslo, Norway.

http://www.cprm.gov.br/33IGC/1350834.html 

The Epoch time article notes that:

"Neither satellite imagery nor sonar 
has been able to find any holes."

The problem here is that "sonar" is not used to find 
impact craters on land. In fact, it would be impossible 
to use sonar for any purpose in the Sahara Desert where 
LDG is found. This misinformation is an excellent 
indication of an extreme lack of understanding of basic 
science, bordering on illiteracy, on the part of this 
article. The stilted and very imprecise use of terminology 
in this article also a basic lack of scientific understanding 
on the part of this article.

For some information on Sonar go read "Sonar" at:

http://en.wikipedia.org/wiki/Sonar 

"...the glass rocks found in the Libyan 
Desert present a grade of transparency 
and purity (99 percent) that is not typical 
in the fusions of fallen meteorites, in 
which iron and other materials are mixed in 
with the cast silicon after the impact."

1. LDG varies greatly in transparency from being almost 
transparent to being either translucent or opaque. There 
is nothing about its transparency that preclude LDG from 
being an impactite.

2. The percentage of silica in LDG matches the percentage 
of silica found in sandstone bedrock that underlies the 
areas in which LDG has been found, the location of at least
two impact structures near the area containing LDG; and 
larges areas of the desert surrounding both the impact 
structures and where LDG is found.

3. The LDG does contain extraterrestrial material derived 
from meteorites / an asteroid mixed in with it. This Epoch
Times article is completely wrong about the absence of an 
extraterrestrial component being presence within LDG.

A few of very many pertinent papers:

Abate, B., Koeberl, C., Kruger, F. J., and Underwood, J. 
R., 1999, BP and Oasis impact structures, Libya, and their 
relation to Libyan Desert Glass. In Dressler, B. O., and 
Sharpton, V. L., eds., Gpp. 177-192. Geological Society 
of America Special Paper no. 339.

Barrat J. A., Jahn B. M., Amosse J., Rocchia R., Keller, 
F., Poupeau G. R., and Diemer E., 1997, Geochemistry and 
origin of Libyan Desert glasses. Geochimica et Cosmochimica 
Acta. vol. 61, no. 9, pp. 1953-1959.

Fudali, R. F., 1981, The major element chemistry of 
Libyan desert glass and the mineralogy of its precursor. 
Meteoritics. vol 16, pp. 247-259.

Kleinmann, B., 1969, The breakdown of zircon observed 
in the Libyan desert glass as evidence of its impact 
origin. Earth and Planetary Science Letters, vol. 5, 
pp. 497-501.

Koeberl, C., 1996, Libyan Desert Glass: geochemical 
composition and origin. In: de Michele, V., ed., 
pp. 121-131, Special publication of the Sahara Journal 
- Silica '96. Proceedings of the Meeting on Libyan 
Desert Glass and Related Events, July 1996, Milano.

Koeberl C., 2000, Confirmation of a meteoric component 
in Libyan Desert Glass from osmium isotopic data. 
Meteoritics & Planetary Science. vol. 35 (Supplement),
pp. A89-A90. 

Koeberl C., Rampino M. R., Jalufka D. A. and Winiarski 
D. H., 2003, A 2003 Expedition into the Libyan Desert 
Glass Strewn Field, Great Sand Sea, Western Egypt. 
Proceedings of the meeting on Large Meteorite Impacts 
(2003), Lunar and Planetary Institute, USRA, Center of 
Advanced Studies, Abstract no. 4079.

This epoch times article also stated:

"However, this doesn't explain how two of 
the areas found in close proximity in the 
Libyan Desert show the same pattern the 
probability of two meteorite impacts so 
close is very low."

Part of the problem here, is that the people who promote 
the Libyan desert glass (LDG) as evidence of ancient 
nuclear warfare ignore the fact that the LDG occurs as 
erosional lags produced by the erosion, transportation 
and redeposition of pieces of it over a period of millions 
of years. Contrary to poetic descriptions by various 
alternative archaeologists and early geologists, the "
glass fields" are not primary deposits formed by the either 
the original airfall, base surge, or in place melting of 
local sand. Rather, the LDG occurs as secondary, even 
tertiary, concentrations, created over 26 million years, 
of the more resistant pieces of LDG. The original Neogene 
deposits, which either contained the LDG or on which formed 
or fell have been eroded and the LDG released from them, 
possibly transported some distance; and concentrated as 
an erosional lag on the ground surface. As a result, the 
current distribution of LDG likely is unrelated to its 
origin. The present distribution of LDG reflects what has 
happened to it over the last 26 million years instead of 
how it was created. 

Finally, the Epoch Times article states:

"Nor does it explain the absence of water 
in the tektite specimens when these areas of 
impact were thought to be covered in it some 
14,000 years ago.'

1. The intense heat of formation of LDG is perfectly capable 
of explaining its extremely low water content.

2. The LDG formed about 29 million years ago, not 14,000 
year ago as this article incorrectly states above. Given 
the age of LDG, it is impossible for this material to have 
any connection with modern humans and manmade objects such 
as nuclear weapons.

A few of many pertinent references:

Horn P., Müller-Sohnius D., Schaaf P., Kleinmann B. and 
Storzer D., 1997, Potassium-argon and fission-track dating 
of Libyan Desert Glass and strontium and neodymium constraints 
on its source rocks. In: de Michele, V., ed., pp. 59-73, 
Special publication of the Sahara Journal - Silica '96. 
Proceedings of the Meeting on Libyan Desert Glass and Related 
Events, July 1996, Milano.

Matsubara, K., Matsuda, J.I., and Koeberl, C., 1991, Noble 
gases and K-Ar ages in Aouelloul, Zhamanshin, and Libyan 
Desert impact glasses. Geochimica et Cosmochimica Acta 
vol. 55, pp. 2951-2955.

This article fails to provide any convincing evidence that
there is any connection between LDG and ancient nuclear 
warefare and that LDG is not an impactite. This Epoch Times
article does provide a lot misinformation and simply ignores
any research that contradicts its preconceived notions about
how LDG might have formed.

Yours,

Paul H