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ABSTRACT: We have collected reflectance spectra of various unprocessed rock samples in the 450-1,650 nm wavelength range with a spatial resolution of 60 and 120 microm (diameter) and using three illumination modes. Spectra taken in diffuse reflectance (dark field) mode are comparable to those obtained from macroscopic measurements and can provide the basis for mineral detection at that spatial scale. The spectral discrimination of the dark field mode is demonstrated to be consistent with the spatial resolution of the microscope for the samples examined. These results support the conclusion that reflectance microspectroscopy in the visible and near-infrared regions can be a valuable tool for understanding mineral formation at the spatial scale of tens of micrometers.
Applied Spectroscopy 01/2009; 62(12):1370-7. · 1.66 Impact Factor
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Albert S. Yen,
Ralf Gellert,
Christian Schröder,
Richard V. Morris,
James F Bell,
Amy T. Knudson,
Benton C. Clark,
Douglas W. Ming,
Joy A. Crisp,
Raymond E. Arvidson, [......],
Harry Y McSween,
Lutz Richter,
Rudi Rieder,
Daniel Rodionov,
Larry Soderblom,
Steven W. Squyres,
Nicholas J. Tosca,
Alian Wang,
Michael Wyatt,
Jutta Zipfel
Nature 08/2005; · 36.28 Impact Factor
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Albert S. Yen,
Ralf Gellert,
Christian Schroder,
Richard V. Morris,
James F 3rd Bell,
Amy T. Knudson,
Benton C. Clark,
Douglas W. Ming,
Joy A. Crisp,
Raymond E. Arvidson, [......],
Thanasis E. Economou,
Amitabha Ghosh,
Brian C. Hahn,
Kenneth E. Herkenhoff,
Larry A. Haskin,
Joel A. Hurowitz,
Bradley L. Joliff,
Jeffrey R. Johnson,
Gostar Klingelhofer,
Morten Bo Madsen
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ABSTRACT: The mineralogical and elemental compositions of the martian soil are indicators of chemical and physical weathering processes. Using data from the Mars Exploration Rovers, we show that bright dust deposits on opposite sides of the planet are part of a global unit and not dominated by the composition of local rocks. Dark soil deposits at both sites have similar basaltic mineralogies, and could reflect either a global component or the general similarity in the compositions of the rocks from which they were derived. Increased levels of bromine are consistent with mobilization of soluble salts by thin films of liquid water, but the presence of olivine in analysed soil samples indicates that the extent of aqueous alteration of soils has been limited. Nickel abundances are enhanced at the immediate surface and indicate that the upper few millimetres of soil could contain up to one per cent meteoritic material.
08/2005;
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Larry A Haskin,
Alian Wang,
Bradley L Jolliff,
Harry Y McSween,
Benton C Clark,
David J Des Marais,
Scott M McLennan,
Nicholas J Tosca,
Joel A Hurowitz,
Jack D Farmer, [......],
James F Bell,
Kenneth Herkenhoff,
Phil R Christensen,
Steve Ruff, Diana Blaney,
Steven Gorevan,
Nathalie A Cabrol,
Larry Crumpler,
John Grant,
Lawrence Soderblom
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ABSTRACT: Gusev crater was selected as the landing site for the Spirit rover because of the possibility that it once held a lake. Thus one of the rover's tasks was to search for evidence of lake sediments. However, the plains at the landing site were found to be covered by a regolith composed of olivine-rich basaltic rock and windblown 'global' dust. The analyses of three rock interiors exposed by the rock abrasion tool showed that they are similar to one another, consistent with having originated from a common lava flow. Here we report the investigation of soils, rock coatings and rock interiors by the Spirit rover from sol (martian day) 1 to sol 156, from its landing site to the base of the Columbia hills. The physical and chemical characteristics of the materials analysed provide evidence for limited but unequivocal interaction between water and the volcanic rocks of the Gusev plains. This evidence includes the softness of rock interiors that contain anomalously high concentrations of sulphur, chlorine and bromine relative to terrestrial basalts and martian meteorites; sulphur, chlorine and ferric iron enrichments in multilayer coatings on the light-toned rock Mazatzal; high bromine concentration in filled vugs and veins within the plains basalts; positive correlations between magnesium, sulphur and other salt components in trench soils; and decoupling of sulphur, chlorine and bromine concentrations in trench soils compared to Gusev surface soils, indicating chemical mobility and separation.
Nature 08/2005; 436(7047):66-9. · 36.28 Impact Factor
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Albert S Yen,
Ralf Gellert,
Christian Schröder,
Richard V Morris,
James F Bell,
Amy T Knudson,
Benton C Clark,
Douglas W Ming,
Joy A Crisp,
Raymond E Arvidson, [......],
Harry Y McSween,
Lutz Richter,
Rudi Rieder,
Daniel Rodionov,
Larry Soderblom,
Steven W Squyres,
Nicholas J Tosca,
Alian Wang,
Michael Wyatt,
Jutta Zipfel
[show abstract]
[hide abstract]
ABSTRACT: The mineralogical and elemental compositions of the martian soil are indicators of chemical and physical weathering processes. Using data from the Mars Exploration Rovers, we show that bright dust deposits on opposite sides of the planet are part of a global unit and not dominated by the composition of local rocks. Dark soil deposits at both sites have similar basaltic mineralogies, and could reflect either a global component or the general similarity in the compositions of the rocks from which they were derived. Increased levels of bromine are consistent with mobilization of soluble salts by thin films of liquid water, but the presence of olivine in analysed soil samples indicates that the extent of aqueous alteration of soils has been limited. Nickel abundances are enhanced at the immediate surface and indicate that the upper few millimetres of soil could contain up to one per cent meteoritic material.
Nature 08/2005; 436(7047):49-54. · 36.28 Impact Factor
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Larry A. Haskin,
Alian Wang,
Bradley L. Jolliff,
Harry Y. McSween,
Benton C. Clark,
David J. Des Marais,
Scott M. McLennan,
Nicholas J. Tosca,
Joel A. Hurowitz,
Jack D. Farmer, [......],
James F. Bell,
Kenneth Herkenhoff,
Phil R. Christensen,
Steve Ruff, Diana Blaney,
Steven Gorevan,
Nathalie A. Cabrol,
Larry Crumpler,
John Grant,
Lawrence Soderblom
[show abstract]
[hide abstract]
ABSTRACT: Gusev crater was selected as the landing site for the Spirit rover because of the possibility that it once held a lake. Thus one of the rover's tasks was to search for evidence of lake sediments
Nature 07/2005; 436(7047):66-69. · 36.28 Impact Factor
