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Thursday's NASA news conference is archived he
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/scienceastronom...er_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/galle...20040315a.html The dark mystery material is in the far side crater wall. Bob Clark |
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This mystery material on Humphrey and in Bonneville may be related to
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 ). 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 ---------------------------------------------------------------- For email response, send to same userid as above, but append Hotmail.com instead of Yahoo.com. ---------------------------------------------------------------- (Robert Clark) wrote in message . com... Thursday's NASA news conference is archived he 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/scienceastronom...er_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/galle...20040315a.html The dark mystery material is in the far side crater wall. Bob Clark |
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The spectrometer is limited that it can only make one average reading in
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. |
#5
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![]() "Robert Clark" 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 |
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This article seems to be lamenting the lack of key discoveries by the
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/process...2L234567M1.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/m..._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/process...5L234567M1.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/np...PI....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/np...car..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 (Robert Clark) wrote in message . com... In the latest news conference was mentioned that the Mazatzal rock was 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 he http://mars.systemsfirst.com 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 (Robert Clark) wrote in message . com... This mystery material on Humphrey and in Bonneville may be related to 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 ). 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 ---------------------------------------------------------------- For email response, send to same userid as above, but append Hotmail.com instead of Yahoo.com. ---------------------------------------------------------------- (Robert Clark) wrote in message . com... Thursday's NASA news conference is archived he 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/scienceastronom...er_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/galle...20040315a.html The dark mystery material is in the far side crater wall. Bob Clark |
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