Abstract

A dark-brown coating on the exterior of a World War II metal fuel can recovered in southwestern Egypt may be a variation of the desert varnish that develops on rock surfaces in arid regions. This suggestion is supported by results of infrared spectroscopic work, x-ray diffraction, scanning electron microscopic studies, and x-ray fluorescence. Exterior portions of the can resemble heavily varnished rock, differing completely in appearance and texture from rusty areas which had developed on portions of the interior surface. The coating consists principally of microscopic mineral deposits, some of which appear to be largely Fe-oxides and Fe-oxy-hydroxides. However many deposits are assemblages of Fe-oxides, clay minerals, and other elements typically occurring in forms of desert varnish often observed on the undersides of desert pavement stones in contact with the soil. Associated with the mineral matter is an organic component apparently deriving from residues of an original paint layer which had been removed by wind/sand scouring.

Examining natural rock varnish and weathering rinds with laser-induced breakdown spectroscopy for application to ChemCam on Mars

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Appl. Opt. 51(7) B74-B82 (2012)

Spectral Absorption Characteristics of the Major Components of Dust Clouds

D. F. Flanigan and H. P. DeLong
Appl. Opt. 10(1) 51-57 (1971)

A novel approach for simulating light interaction with particulate materials: application to the modeling of sand spectral properties

BradleyW. Kimmel and Gladimir V.G. Baranoski
Opt. Express 15(15) 9755-9777 (2007)

Mineralogical Investigations of Mars

J. T. O'Connor
Appl. Opt. 8(7) 1323-1328 (1969)

Rainbows in the Indian rock art of desert western America

Kenneth Sassen
Appl. Opt. 30(24) 3523-3537 (1991)