Publications
Filter Total Items: 334
Using imaging spectroscopy to map acidic mine waste
The process of pyrite oxidation at the surface of mine waste may produce acidic water that is gradually neutralized as it drains away from the waste, depositing different Fe-bearing secondary minerals in roughly concentric zones that emanate from mine-waste piles. These Fe-bearing minerals are indicators of the geochemical conditions under which they form. Airborne and orbital imaging spectrometer
Authors
G.A. Swayze, K. S. Smith, R. N. Clark, S. J. Sutley, R.M. Pearson, J.S. Vance, P. L. Hageman, Paul H. Briggs, A. L. Meier, M.J. Singleton, S. Roth
Identification of a basaltic component on the Martian surface from Thermal Emission Spectrometer data
The Mars Global Surveyor Thermal Emission Spectrometer (TES) instrument collected 4.8×106 spectra of Mars during the initial aerobraking and science‐phasing periods of the mission (September 14, 1997, through April 29, 1998). Two previously developed atmosphere‐removal models were applied to data from Cimmeria Terra (25°S, 213°W). The surface spectra derived for these two models agree well, indica
Authors
P. R. Christensen, J. L. Bandfield, M. D. Smith, V.E. Hamilton, Roger N. Clark
Distribution of altered rock material in the Kerber Creek drainage basin, Saguache County, Colorado
No abstract available.
Authors
K.E. Livo, Ken Watson, D. H. Knepper, Susanne Hummer-Miller
Hydrogen peroxide on the surface of Europa
Spatially resolved infrared and ultraviolet wavelength spectra of Europa's leading, anti-jovian quadrant observed from the Galileo spacecraft show absorption features resulting from hydrogen peroxide. Comparisons with laboratory measurements indicate surface hydrogen peroxide concentrations of about 0.13 percent, by number, relative to water ice. The inferred abundance is consistent with radiolyti
Authors
R. W. Carlson, M.S. Anderson, R.E. Johnson, W. D. Smythe, A.R. Hendrix, C.A. Barth, L. A. Soderblom, G. B. Hansen, T. B. McCord, J.B. Dalton, R. N. Clark, J.H. Shirley, A.C. Ocampo, D. L. Matson
Spectroscopic determination of leaf biochemistry using band-depth analysis of absorption features and stepwise multiple linear regression
We develop a new method for estimating the biochemistry of plant material using spectroscopy. Normalized band depths calculated from the continuum-removed reflectance spectra of dried and ground leaves were used to estimate their concentrations of nitrogen, lignin, and cellulose. Stepwise multiple linear regression was used to select wavelengths in the broad absorption features centered at 1.73 ??
Authors
R.F. Kokaly, R. N. Clark
Spectroscopy of rocks and minerals and principles of spectroscopy
Spectroscopy is the study of light as a function of wavelength that has been emitted, reflected or scattered from a solid, liquid, or gas. In this chapter I will primarily discuss the spectroscopy of minerals, but the principles apply to any material. No single chapter can cover this topic adequately, and one could argue, not even a single book. Thus, in some ways, this chapter may fall short of e
Authors
Roger N. Clark
Non-water-ice constituents in the surface material of the icy Galilean satellites from the Galileo near-infrared mapping spectrometer investigation
We present evidence for several non‐ice constituents in the surface material of the icy Galilean satellites, using the reflectance spectra returned by the Galileo near infrared mapping spectrometer (NIMS) experiment. Five new absorption features are described at 3.4, 3.88, 4.05, 4.25, and 4.57 μm for Callisto and Ganymede, and some seem to exist for Europa as well. The four absorption bands strong
Authors
T. B. McCord, G. B. Hansen, Roger N. Clark, P. D. Martin, C. A. Hibbitts, F. P. Fanale, J. C. Granahan, M. Segura, D. L. Matson, T. V. Johnson, R. W. Carlson, W. D. Smythe, G. E. Danielson
Results from the Mars global surveyor thermal emission spectrometer
The Thermal Emission Spectrometer spectra of low albedo surface materials suggests that a four to one mixture of pyroxene to plagioclase, together with about a 35 percent dust component provides the best fit to the spectrum. Qualitative upper limits can be placed on the concentration of carbonates (
Authors
P. R. Christensen, D.L. Anderson, S.C. Chase, R.T. Clancy, R. N. Clark, B.J. Conrath, H. H. Kieffer, R.O. Kuzmin, M. C. Malin, J.C. Pearl, T. L. Roush, M. D. Smith
Organics and other molecules in the surfaces of Callisto and Ganymede
Five absorption features are reported at wavelengths of 3.4, 3.88, 4.05, 4.25, and 4.57 micrometers in the surface materials of the Galilean satellites Callisto and Ganymede from analysis of reflectance spectra returned by the Galileo mission near-infrared mapping spectrometer. Candidate materials include CO2, organic materials (such as tholins containing C???N and C-H), SO2, and compounds contain
Authors
T. B. McCord, R. W. Carlson, W. D. Smythe, G. B. Hansen, R. N. Clark, C. A. Hibbitts, F. P. Fanale, J. C. Granahan, M. Segura, D. L. Matson, T. V. Johnson, P. D. Martin
The distribution of sulfur dioxide and other infrared absorbers on the surface of Io
The Galileo Near Infrared Mapping Spectrometer was used to investigate the distribution and properties of sulfur dioxide over the surface of Io, and qualitative results for the anti‐Jove hemisphere are presented here. SO2, existing as a frost, is found almost everywhere, but with spatially variable concentration. The exceptions are volcanic hot spots, where high surface temperatures promote rapid
Authors
R. W. Carlson, W. D. Smythe, R. M. C. Lopes-Gautier, A.G. Davies, L.W. Kamp, J. A. Mosher, L. A. Soderblom, F.E. Leader, R. Mehlman, Roger N. Clark, F. P. Fanale
Hydrous carbonates on Mars?: Evidence from Mariner 6/7 infrared spectrometer and ground‐based telescopic spectra
Absorption features at 2.28 and 5.4 μm identified in Mariner 6/7 infrared spectrometer and terrestrial telescopic spectra are consistent with the spectra of hydrous magnesium carbonates such as hydromagnesite and artinite. Spectral characteristics of these hydrous carbonates are different from those of the anhydrous carbonates, as the former do not have the strong spectral features typically assoc
Authors
W. M. Calvin, T. V. V. King, Roger N. Clark
Spectral Distinctions between the Leading and Trailing Hemispheres of Callisto: New Observations
An analysis of recent telescopic observations of Callisto results in new insights regarding spectral variations from the leading to the trailing hemisphere of Callisto. Examination of data in the wavelength range from 2.0 to 2.5 ??m indicates that previous suggestions of spectral differences are most likely the result of experimental uncertainty or error. Slight variations in the slope of this wav
Authors
W. M. Calvin, R. N. Clark