Ramblings about what I encounter within the realm of the geosciences, as well as the occasional rant about nonsense.

05 March 2008

The Importance of Desert Varnish

Apparently, it may be possible to use desert varnish as an indicator of former life. While the varnish can form abiotically, it will incorporate biologic material into its structure. The authors claim this mechanism can preserve this evidence in multi-billion year old deposits, I find that claim a bit of a reach. Genetic material tends to break down after a couple thousand years. Other indicators, like amino acids, may last longer but I am unsure of that.

The big difference between the press release and the actual article is the focus. The press release focuses entirely upon the Martian applications that the desert varnish has. Whereas the journal article's key point is that the formation of silica gels is more important to desert varnish formation than manganese. The article also makes the argument that organic material can enhance and accelerate the processes through which desert varnish forms (it can also slow it down, if there is too much water though). It also makes ties between silica gel deposits worldwide and those that are currently considered separate phenomena (lumped together as desert varnish).

I guess I understand the reason why the press release emphasizes a facet of the study that was covered in less than 2 sentences, but I still find the whole occurrence bizarre.

Click here for the press release

Click here for the pdf (via geoscienceworld, subscription required)
Click here for the pdf (via geology, subscription required)

Baking black opal in the desert sun: The importance of silica in desert varnish Geology Volume 34, Number 7, July 2006
Randall S. Perry (1),(6), Bridget Y. Lynne (2), Mark A. Sephton (1), Vera M. Kolb (3), Carole C. Perry (4), James T. Staley (5)

(1) Department of Earth Science and Engineering, Imperial College London, UK
(2) Department of Geology, University of Auckland, New Zealand
(3) Department of Chemistry, University of Wisconsin-Parkside, USA
(4) Chemistry Division, Nottingham Trent University, UK
(5) Department of Microbiology, University of Washington, USA
(6) Planetary Science Institute, Washington, USA

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All the Latin on this page is from my vague recollections from High School. There are mistakes in the text. I just was trying to get the point across

Between Los Alamos,NM and White Rock, NM

Between Los Alamos,NM and White Rock, NM
The photo of the travertine spring was taken in the small opening in the center of the image.

Lectio Liber