[meteorite-list] Was There Life on Mars? Shiny Rock Coating May Hold the Answer

From: joseph_town_at_att.net <joseph_town_at_meteoritecentral.com>
Date: Fri Jun 30 17:30:06 2006
Message-ID: <063020062039.29614.44A58BE700003375000073AE21587667550299019BA1089F0A9C0106_at_att.net>

How could Martian desert varnish survive ablation? This is crazy talk.

Bill


 -------------- Original message ----------------------
From: Ron Baalke <baalke_at_zagami.jpl.nasa.gov>
>
> http://www.imperial.ac.uk/P7911.htm
>
> Was there life on Mars? Shiny rock coating may hold the answer
>
> Imperial College London News Release
> For immediate release
> Friday 30 June 2006
>
> A mysterious shiny coating found on rocks in many of Earth's arid
> environments could reveal whether there was once life on Mars, according
> to new research.
>
> The research, published in the July edition of the journal Geology,
> reveals that the dark coating known as desert varnish creates a record
> of life around it, by binding traces of DNA, amino acids and other
> organic compounds to desert rocks. Samples of Martian desert varnish
> could therefore show whether there has been life on Mars at any stage
> over the last 4.5 billion years.
>
> The source of desert varnish has intrigued scientists since the mid
> nineteenth century
>
> The researchers hope that these results will encourage any future Mars
> Sample Return mission to add desert varnish to its Martian shopping list.
>
> The source of the varnish, which looks like it has been painted onto the
> rocks, has intrigued scientists since the mid nineteenth century,
> including Darwin, who was so fascinated that he asked the geochemist
> Berzelius to investigate it. It was previously suggested that its dark
> colour was the result of the presence of the mineral manganese oxide,
> and that any traces of life found within the varnish came from
> biological processes caused by microbes in this mineral.
>
> However, the new research used a battery of techniques, including high
> resolution electron microscopy, to show that any traces of life in the
> varnish do not come from microbes in manganese oxide. The research
> reveals that the most important mineral in the varnish is silica, which
> means that biological processes are not significant in the varnish's
> formation. On desert rock surfaces, silica is dissolved from other
> minerals and then gels together to form a glaze, trapping organic traces
> from its surroundings.
>
> Desert varnish was used to create images known as petroglyphs like these
> in Grimes Point, Nevada
>
> Dr Randall Perry, lead author of the research from the Department of
> Earth Science and Engineering at Imperial College London, explained that
> as life is not involved in desert varnish formation, the varnish can act
> as an indicator of whether life was present or absent in the local
> environment.
>
> Dr Perry said: "If silica exists in varnish-like coatings in Martian
> deserts or caves, then it may entomb ancient microbes or chemical
> signatures of previous life there, too. Desert varnish forms over tens
> of thousands of years and the deepest, oldest layers in the varnish may
> have formed in very different conditions to the shallowest, youngest layer.
>
> "These lustrous chroniclers of the local surroundings can provide a
> window back in time. Martian desert varnish would contain a fascinating
> chronology of the Martian setting," he added.
>
> The research was carried out by researchers at Imperial College and the
> Universities of Auckland (NZ); Wisconsin-Parkside and Washington (US);
> and Nottingham Trent (UK).
>
> *** Images of rocks covered with black desert varnish in Death Valley
> California and Petroglyphs from Grimes Point Nevada (dating back
> thousands of years) are available ***
>
> -ends-
>
> For further information please contact:
>
> Laura Gallagher
> Imperial College London Press Office
> Email: l.gallagher_at_imperial.ac.uk
> Tel: 020 7594 6702
>
> Notes to editors:
>
> 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
> An online preview edition of the paper can be viewed here:
> wwwgsajournals.org/gsaonline/?request=get-document&doi=10.1130%2FG22352A.1
> <http://www.gsajournals.org/gsaonline/?request=get-document&doi=10.1130%2FG22352
> A.1>
>
> About desert varnish
>
> * Desert varnish is found across the world in areas including the
> Atacama desert in Chile, the Mojave desert in Southern California, USA
> and Canyonlands National Park, Utah, USA.
>
> * It is often found on canyon walls.
>
> * It is one of fourteen different types of rock coatings.
>
> * Desert varnish was used by prehistoric and Neolithic people to create
> images known as petroglyphs, which they crafted by scraping away the
> dark varnish to reveal the light rock underneath.
>
> * Desert varnish is sometimes mistaken for fusion crust, the melted
> glassy exterior of a meteorite that forms when the meteorite passes
> through the atmosphere.
>
> About Imperial College London
>
> Consistently rated in the top three UK university institutions, Imperial
> College London is a world leading science-based university whose
> reputation for excellence in teaching and research attracts students
> (11,000) and staff (6,000) of the highest international quality.
> Innovative research at the College explores the interface between
> science, medicine, engineering and management and delivers practical
> solutions that enhance the quality of life and the environment -
> underpinned by a dynamic enterprise culture.
> Website: www.imperial.ac.uk
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Received on Fri 30 Jun 2006 04:39:04 PM PDT