Mystery material in the Bonneville crater on Mars.
Robert Clark
http://mars.systemsfirst.com/news_archive/index.html
About 43 minutes in is discussed the dark deposits inside the crater.
Dr. John Grant said the dark deposits in the crater were like a
mystery material on the Humphrey rock examined by Spirit. This
material was either glass-like or a weathering product, presumably due
to liquid water, since it was found to have been exposed to small
amounts of liquid water weathering:
Take That Opportunity: Spirit Rover Finds Own Water To Play In
http://www.space.com/scienceastronomy/spirit_water_040305.html
Grant said the dark material in the drift outside Bonneville crater
was not like this, but more like the classic basaltic material.
If this mystery material is due to liquid water weathering, examining
up close would give us a chance to see a large-scale deposit of liquid
water altered minerals at the Gusev site.
Bonneville in Color.
http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040315a.html
The dark mystery material is in the far side crater wall.
Bob Clark
Robert Clark
the second class of volcanic rock observed from orbit by the TES
spectrometer aside from basalt.
The original interpretation was that it was andesitic rock. However,
another interpretation has been proposed that it may in fact be basalt
weathered by liquid water:
The Tricky Business of Identifying Rocks on Mars
--- A new analysis of thermal emission spectra suggests a new
interpretation for the composition of the Martian surface.
Written by G. Jeffrey Taylor
Hawai'i Institute of Geophysics and Planetology
http://www.psrd.hawaii.edu/May02/MarsTES.html
As with the rover observations of the Humphrey rock, this 2nd type of
rock, referred to as Surface Type 2, contains either high silica glass
or basalt weathering products, clays for example.
These reports given at the last weeks Lunar and Planetary Science
Conference also discuss these two possibilities for this Surface Type
2 material:
VOLCANISM AND/OR AQUEOUS ALTERATION ON MARS: CONSTRAINTS ON
DISTINGUISHING
GLASS AND PHYLLOSILICATE IN THE THERMAL INFRARED. W. C. Koeppen and V.
E. Hamilton, Hawaii Institute of Geophysics and Planetology,
University of Hawaii at Manoa, 1680 East-West Rd, POST 602, Honolulu,
HI 96822 (****@higp.hawaii.edu).
Lunar and Planetary Science XXXV (2004) 1457.pdf
http://www.lpi.usra.edu/meetings/lpsc2004/pdf/1457.pdf
Emission spectroscopy of smectites: Implications for the TES
andesite-weathered basalt debate. Joseph. R. Michalski1, Michael D.
Kraft1, Thomas G. Sharp1, Lynda B. Williams 2, and Philip R.
Christensen1 1 Dept. of Geological Sciences, Arizona State University,
Tempe, AZ, 85287-1404 2 Center for Solid State Science, Arizona State
University.
Lunar and Planetary Science XXXV (2004) 1401.pdf
http://www.lpi.usra.edu/meetings/lpsc2004/pdf/1401.pdf
Interestingly the first suggests they might be distinguished by up
close examination by a lander spectrometer whereas orbital
determinations are obscured by atmospheric CO2 absorptions.
Then detailed measurements of the dark material in Bonneville by the
Spirit rover may be able to resolve this question about the origin of
the Surface Type 2 rock on Mars.
As explained in the web article by G. Jeffrey Taylor above, both the
andesitic and weathered basalt explanations have important
implications for the geologic past of Mars - the andesitic, suggesting
tectonic plates may have operated on Mars, and the weathered basalt,
suggesting liquid water oceans may have occurred on Mars.
Bob Clark
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rgrego...@yahoo.com (Robert Clark) wrote in message news:<832ea96d.04032...@posting.google.com>...
rick++
the 2" by 2" window. Therefore they look for regions completely absent
of mineralization, then rich regions to get comparable spectra.
Thats what took a while to determine the nodules were hematite.
Robert Clark
subject to liquid water weathering as was the Humphrey rock. But
interestingly it seems to have been subjected to several separate
water exposures. This might be consistent with the theory that Mars
undergoes periodic cycles of relatively clement climate.
News conference archived here:
It was also mentioned that several brushings were made on the rock to
create a larger area for the mini-TES spectrometer to get a good
reading of its mineralogy.
Since the dark material in Bonneville crater seems to have similar
spectral features as Mazatzal and Humphrey it would be a good idea to
have Spirit take a close up view of this material using the Pancam
imager and mini-TES. This might be possible to do without having to go
into the crater since the dark material extends far up the sides.
Bob Clark
Joe Knapp
"Robert Clark" <rgrego...@yahoo.com> wrote
> It was also mentioned that several brushings were made on the rock to
> create a larger area for the mini-TES spectrometer to get a good
> reading of its mineralogy.
Here's a color composite of the Mazatzal rock art:
http://copperas.com/astro/mazart.jpg
Joe
Robert Clark
Spirit rover compared to the Opportunity rover:
Mars Water Past Still Mysterious
by Phil Berardelli
Washington (UPI) Apr 16, 2004
http://www.spacedaily.com/news/mars-mers-04zzzv.html
I wanted Spirit to at least drive to the far side rim of Bonneville
to get a closer look at the dark material on the far side of
Bonneville:
Spirit, Sol 84
http://www.lyle.org/~markoff/processed/2P133828474ESF2232P2592L234567M1.JPG
Mini-TES observations from a distance showed it to have the same
composition as dark material in the subsurface of Humphrey rock.
MARS EXPLORATION ROVERS UPDATE
Spirit Returns Color Panorama of Bonneville Crater
Opportunity Finds 'Blueberries' Are Loaded with Hematite
By A.J.S. Rayl
20 March 2004
http://www.planetary.org/news/2004/mer-update_04-03-20.html
This mystery material was either a glassy silica or a weathered
basalt. This is similar to the mystery material known to make up much
of Mars northern hemisphere from TES measurements, which is believed
to be either an andesite or a liquid water altered basalt. The rover
might have been able to decide between these two possibilities.
Rover scientists did not want to chance driving into the crater. But
as you can see from the Sol 84 image, this dark material extends far
enough up the sides the rover probably could have gotten a good look
at this material without going down into the crater.
However, later images of the Columbia hills show similar dark material
partially up the sides of the hills and in the region between the
hills and Spirit:
Spirit, Sol 91
http://www.lyle.org/~markoff/processed/2P134451314EFF2700P2375L234567M1.JPG
So it might still be possible to determine the composition of this
dark material.
Additionally, Natalie Cabrol an expert on Gusev Crater where Spirit
landed, has argued there may be frost mounds in Gusev:
Title: Perennial frost mounds in Gusev crater (Mars)
Authors: Cabrol, N. A.; Grin, E. A.; Pollard, W. H.
Journal: Conference Paper, 28th Annual Lunar and Planetary Science
Conference, p. 193.
Publication Date: 03/1997
http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1997LPI....28..193C
Title: Possible Frost Mounds in an Ancient Martian Lake Bed
Authors: Cabrol, Nathalie A.; Grin, Edmond A.; Pollard, Wayne H.
Journal: Icarus, Volume 145, Issue Icarus, pp. 91-107.
http://adsabs.harvard.edu/cgi-bin/nph-bib_query?2000Icar..145...91C
In her examples taken from MOC images of Gusev, some of the proposed
frost mounds have a sinuous shape not just a conical shape. Then these
could match the shape of the Columbia Hills.
The areas where the proposed frost mounds lie also include the
Columbia Hills.
Bob Clark
rgrego...@yahoo.com (Robert Clark) wrote in message news:<832ea96d.04040...@posting.google.com>...