Science Frontiers ONLINE No. 64: Jul-Aug 1989 Issue Contents

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Libyan Desert Glass

Pieces of Libyan Desert Glass weighing as much as 16 pounds are found in an oval area measuring approximately 130 by 53 kilometers. The clear-to-yellowish-green pieces are concentrated in sand-free corridors between north-south dune ridges. The origin of this immense deposit of glass has been attributed by some to ancient nuclear explosions and alien activities, but investigating scientists have always been satisfied with a meteor-impact hypothesis. A recent study (abstract below) also opts for this explanation, although no one has found a crater of suitable size or other supporting evidence.

"Libyan Desert Glass (LDG) represents 1.4 x 10⁹ g of natural glass fragments scattered over about 6500 km² of the western Desert of Egypt. We made a systematic study (employing INAA, microprobe and mass spectrometry techniques) of several varieties of LDG and locally associated sand and sandstone to provide insight into the nature and formation of these enigmatic glass fragments. These studies indicate that:

1. Although the LDG has restricted major element compositions (97.98 wt% SiO₂ ; 1-2 wt % Al₂ O₃ ) their trace element contents (ppm) (Fe, 490-5200; Co, 0.2-1.2; Cr, 1.2-29 and Sc. 0.462.5) vary by as much as a factor of 5 to 30.

2. The LDG fragments exhibit a factor of three variation in the REE abundances (La, 5.4-15.3 ppm). They all show parallel and steep LREE enriched patterns ([La/Sm]_N , 3.8-4.2) and flat HREE ([Tb/Lu]_N , 1.1- 1.2) and distinct negative europium anomalies (Eu/Eu*, about 0.5).

3. The gases in the vesicles of LDG (N₂ , Ar, O₂ , CO₂ , H₂ O and their dissociation products) are present in proportions consistent with derivation from the terrestrial atmosphere.

4. Dark streaks present in some samples of LDG contain significantly higher siderophile element abundances (Ir, about 0.5 ppb), possibly representing a meteoritic residue.

"Our studies suggest that LDG is the product of meteorite impact into quartz-rich surficial eolion and alluvial sand, and perhaps also into quartz-rich sandstone, of the western Desert of Egypt."

(Murall, A.V., et al; Eos, 70: 379, 1989.)

Reference. Libyan desert glass and other unusual natural glasses are cataloged in ESM2 in Neglected Geological Anomalies. To order this catalog, visit here.

From Science Frontiers #64, JUL-AUG 1989. © 1989-2000 William R. Corliss

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Science Frontiers Sourcebook Project Reviewed in: Booklist: December 15, 1977 New York Times: April 3, 1979 Icarus: Volume 41, Issue 3, p. 470-470 1980, Vol.56:3, P.615 1983, Vol.58:3 June 1984, Vol.60:3 Dec 1984, Vol.72:3 Dec 1987 Library Journal: June 1, 1981 The Science Teacher: March 1983 Choice: June 1982; September 1983 Science Books and Films, Sept/Oct 1983 Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 1987 American Journal of Physics, Volume 52, Issue 8, p. 764 August 1984 Quotes "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980 "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983 "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983 "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987