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#1 2006-09-10 18:17:31

RGClark
Member
From: Philadelphia, PA
Registered: 2006-07-05
Posts: 720
Website

Re: Clays in Meridiani.

Just saw this on Unmannedspaceflight.com:

Mineralogy of the light-toned outcrop at Meridiani Planum as seen by
the Miniature Thermal Emission Spectrometer and implications for its
formation.
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 111, E12S03,
doi:10.1029/2005JE002672, 2006
"Abstract
Analysis of Miniature Thermal Emission Spectrometer (Mini-TES) data has
led to the recovery of a pure end-member spectral shape related to the
light-toned outcrop observed at Meridiani Planum. Data from the MER
Mössbauer spectrometer, APXS, and previous Mini-TES measurements were
used to constrain a spectral library used to determine the mineralogy
of the outcrop from this spectral shape. Linear deconvolution of the
outcrop spectral shape suggests that it is composed primarily of
Al-rich opaline silica, Mg-, Ca-, and Fe-bearing sulfates, plagioclase
feldspar, nontronite, and hematite. Conversion of modeled mineralogy to
chemistry shows good agreement with the chemical composition of the
outcrops determined by APXS. Details of the analysis procedure and
implications for the formation of the outcrop are discussed along with
terrestrial analogs of the ancient environment at Meridiani."
http://www.gps.caltech.edu/~tglotch/2005JE002672.pdf


According to the authors the spectra of the Meridiani bedrock is best
matched by a composition that includes 10% nontronite clay.


    Bob Clark


Old Space rule of acquisition (with a nod to Star Trek - the Next Generation):

      “Anything worth doing is worth doing for a billion dollars.”

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#2 2006-09-13 17:51:04

RGClark
Member
From: Philadelphia, PA
Registered: 2006-07-05
Posts: 720
Website

Re: Clays in Meridiani.

It was mentioned on sci.astro that "clay-like" material was seen at Meridiani by the MER Opportunity rover:

http://marsrovers.jpl.nasa.gov/gallery/ … 3L2M1.HTML

Two separate and independent observational means show
there is seasonally varying water content on the Martian surface: one
by thermal infrared spectra, the other by the Gamma Ray-Neutron
Spectrometer.
The thermal infrared was from the TES and Mini-TES instruments showing seasonal variations of carbonate dust on the surface. It was suggested this was formed from water vapor.
However, on Earth in nature carbonate is formed from *liquid* water.
It is very likely it is formed from liquid water on Mars as well:

From: Robert Clark
Date: Sat, Feb 11 2006 10:32 pm
Email: "Robert Clark" <rgregorycl>
Groups: sci.astro, alt.sci.planetary, sci.physics, sci.geo.mineralogy
Subject: Could We Make A "Solar Still" On Mars?
http://groups.google.com/group/sci.astr … e350f8c285?

This report shows clays can be formed in short times under martian
conditions:

MINIMUM TIMES TO FORM CLAY IN MARTIAN SURFACE AND NEAR-SURFACE
ENVIRONMENTS.
L. Browning1, G. J. Taylor2, and D. Pickett1
1Center for Nuclear Waste Regulatory Analyses, Southwest Research
Institute, 6220 Culebra Rd., San Antonio, TX 78228 2 Hawai'i
Institute of Geophysics and Planetology, University of Hawaii,
Honolulu, HI, 96822
Lunar and Planetary Science XXXIV (2003) 1708.pdf
http://www.lpi.usra.edu/meetings/lpsc2003/pdf/1708.pdf

I suggest searching the infrared spectra to see if the signature for
clays also varies seasonally as does the carbonate dust signature.
If it does then this will mean the clays are currently forming and
will imply they are also being formed from liquid water as is the
carbonate dust.


Bob Clark


Old Space rule of acquisition (with a nod to Star Trek - the Next Generation):

      “Anything worth doing is worth doing for a billion dollars.”

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