Greg wrote: “I’m wondering if the formation of desert varnish can vary depending on different biological and environmental factors. Perhaps in one area a similar thickness may take a shorter period of time. 100,000 years is a long time, but I guess not that long in geological time. This is interesting in that some meteorites may have been sitting on earth for a very long time.”
Below are some interesting pages about desert varnish: Rock Varnish (desert varnish): An Internet Primer for Rock Art Research by Ronald I. Dorn , Professor of Geography Arizona State University http://alliance.la.asu.edu/dorn/VarnishPages/VarnishPrimerIntro.html Chapter 8 in Geochemical Sediments and Landscapes http://alliance.la.asu.edu/dorn/VarnishPages/GeochemicalSediments/GeochemicalSediments.html http://alliance.la.asu.edu/dorn/DornCh08.pdf Note: the above URL to Chap. 8, has numerous links to PDF file of papers about rock varnish. Desert Varnish http://alliance.la.asu.edu/dorn/DesertVarnishDornFormat.pdf Varnish Microlamination (VML) Dating http://www.vmldating.com/ PDF files of various publication about rock varnish can be downloaded from “Selected Publications on Methodology and Application of VML Dating” at: http://www.vmldating.com/selectedpapers.html Yours, Paul H. ______________________________________________ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list