Desert Varnish: The Importance of Clay Minerals

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Science  24 Jun 1977:
Vol. 196, Issue 4297, pp. 1446-1448
DOI: 10.1126/science.196.4297.1446


Desert varnish has been characterized by infrared spectroscopy, x-ray diffraction, and electron microscopy. It is a distinct morphological entity having an abrupt boundary with the underlying rock. Clay minerals comprise more than 70 percent of the varnish. Iron and manganese oxides constitute the bulk of the remainder and are dispersed throughout the clay layer.