Another biological explanation of the Mars spherules.

This web page may provide an explanation of the shiny subsurface
spherules seen in the trench dug by the Opportunity rover:

Desert Varnish On Rocks And Boulders.
http://waynesword.palomar.edu/pljan98.htm#Desert

Compare to:

February 19, 2004
Opportunity Examines Trench As Spirit Prepares To Dig One.
http://marsrovers.jpl.nasa.gov/newsr...20040219a.html

Shiny surfaces had been seen on rocks at the Viking and Pathfinder
landing sites and had been attributed to rock varnish, also known as
desert varnish. Some scientists believe all rock varnish is biological
in origin while others believe it can have a purely chemical origin.
These LPSC reports suggests the hematite deposits seen on Mars could
be due to such varnishes and notes in their samples biosignatures were
observed:

MICROBIAL FOSSILS DETECTED IN DESERT VARNISH.
B.E. Flood1, C. Allen2 and T. Longazo3, 1Texas A&M
University at Galveston, Texas 77554, , 2
Astromaterials Research and Exploration Science, NASA
Johnson Space Center, Houston, TX 77058, 3Hernandez Engineering, NASA
Johnson Space Center, Houston, TX 77058
http://www.lpi.usra.edu/meetings/lpsc2003/pdf/1633.pdf

DESERT VARNISH – PRESERVATION OF BIOFABRICS AND IMPLICATIONS FOR MARS.
Luke W. Probst1, Carlton C. Allen2, Kathie L. Thomas-Keprta3, Simon J.
Clemett3, Teresa G. Longazo4, Mayra A.
Nelman-Gonzalez5 , and Clarence Sams2 1Bemidji State University,
Bemidji, MN 56601
2NASA Johnson Space Center, Houston, TX 77058, 3Lockheed Martin Space
Operations, Houston, TX 77058,
4Hernandez Engineering, Houston, TX 77062, 5Wyle Life Sciences,
Houston, TX 77058.
http://www.lpi.usra.edu/meetings/lpsc2002/pdf/1764.pdf

MAGNETITE IN DESERT VARNISH AND APPLICATIONS TO ROCK VARNISH ON MARS.
R. L. Mancinelli1
), J. L. Bishop1, S. De2, 1SETI
Institute/NASA-ARC, MS 239-4, Moffett Field, CA 94035,
2Exobiology Branch, NASA-ARC, MS 239-4, Moffett Field, CA 94035.
http://www.lpi.usra.edu/meetings/lpsc2002/pdf/1046.pdf


I had thought of the varnish as providing an explanation of the shine
in the subsurface spherules, but some examples on the "Desert Varnish
On Rocks And Boulders" page may provide an explanation of the
spherules themselves:

Crustose Marine Lichens Of The Pacific Coast.
http://waynesword.palomar.edu/pljan98.htm#maura2.gif

See the close-up image of the lichen Verrucaria maura. The round
bodies here look similar to those seen at the Opportunity site.

See also these examples:

Verrucaria maura Wahlenb. (a lichen)
http://www.bioimages.org.uk/HTML/P163349.HTM

Verrucaria maura.
http://www.theseashore.org.uk/theseashore/V.maura%20SRS(US).html


Bob Clark

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