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The manganese- and iron-oxide mineralogy of desert varnish

Potter, Russell M. and Rossman, George R. (1979) The manganese- and iron-oxide mineralogy of desert varnish. Chemical Geology, 25 (1-2). pp. 79-94. ISSN 0009-2541. doi:10.1016/0009-2541(79)90085-8.

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Birnessite and hematite have been identified as the Mn- and Fe-oxide phases in desert varnish by IR spectroscopic and chemical techniques. These oxides are in intimate physical association with the mixed-layer illite—montmorillonite clay minerals of varnish. An abrupt change in chemistry, mineralogy and morphology exists at the varnish—rock interface. The origin of the material appears to be external to the rock which it coats. The oxides appear to be transported by water, and it is most likely that the clays are transported by wind or water. Clay minerals are necessary for varnish formation, probably through their influence on oxide concentration or deposition.

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Rossman, George R.0000-0002-4571-6884
Additional Information:© 1979 Elsevier Scientific Publishing Company. Received July 12, 1978; accepted for publication July 24, 1978. R.P. Sharp provided helpful discussions regarding field localities. D.E. Martin and R.N. Rodgers gave us the benefit of their field observations of desert varnish. J.C. Bard, M. Furst, J.D. Hayden, A.J. Jelinek, and R.S. Perry provided samples to test the generality of our results. J.P. Revel made available scanning electron microscope and photographic equipment and P.F. Koen assisted in their use. Financial support was provided primarily by the L.S.B. Leaky and the John A. McCarthy Foundations.
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L. S. B. Leaky FoundationUNSPECIFIED
John A. McCarthy FoundationUNSPECIFIED
Issue or Number:1-2
Record Number:CaltechAUTHORS:20130416-094741333
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Official Citation:Russell M. Potter, George R. Rossman, The manganese- and iron-oxide mineralogy of desert varnish, Chemical Geology, Volume 25, Issues 1–2, April 1979, Pages 79-94, ISSN 0009-2541, 10.1016/0009-2541(79)90085-8. (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:37960
Deposited On:16 Apr 2013 17:01
Last Modified:09 Nov 2021 23:32

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