Silica, amino acids, and DNA were recently discovered in desert varnish. In this work we experimentally test the proposed role of silicic acid and bio-chemicals in the formation of desert varnish and other rock coatings. We have developed a protocol in which hte rocks were treated with a mixture of silicic acid, sugars, amino acids, metals and clays, under the influence of heat and UV light. This protocol reflects the proposed mechanism of hte polymerization of silicic acid with the bioorganic materials, and the laboratory model for the natural conditions under which the desert varnish is formed. Our experiments produced coatings with a hardness and morphology that resemble the nature ones. These results provide a support for the role of silicic acid in the formation of rock coatings. Since the hard silica-based coatings preserve organic compounds in them, they may serve as a biosignature for life, here or possibly Mars.
Revised: October 22, 2009 |
Published: December 1, 2004
Citation
Kolb V., A.I. Philip, and R.S. Perry. 2004.Testing the Role of Silicic Acid and Bioorganic Materials in the Formation of Rock Coatings. In Proceedings of SPIE -- Instruments, Methods and Missions for Astrobiology VIII, edited by RB Hoover, GV Levin, AY Rozanov, 5555, 116-125. Bellingham, Washington:SPIE.