Publications
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High spectral resolution reflectance spectroscopy of minerals
The reflectance spectra of minerals are studied as a function of spectral resolution in the range from 0.2 to 3.0 μm. Selected absorption bands were studied at resolving powers (λ/Δλ) as high as 2240. At resolving powers of approximately 1000, many OH‐bearing minerals show diagnostic sharp absorptions at the resolution limit. At low resolution, some minerals may not be distinguishable, but as the
Authors
R. N. Clark, T. V. V. King, M. Klejwa, Gregg A. Swayze, N. Vergo
Infrared spectra and crystal chemistry of scapolites: implications for Martian mineralogy
Near‐infrared and midinfrared spectra of a wide range of scapolite compositions were studied to determine the cause of the 2.36‐μm features that have been correlated with similar features in the near‐IR spectrum of Mars. We attribute the 2.36−μm features to vibrations caused by HCO3− and HSO4− in the anion sites of scapolite. The 2.36‐μm absorption complex consists of four overlapping bands with t
Authors
Gregg A. Swayze, Roger N. Clark
High-resolution reflectance spectra of Mars in the 2.3-μm region: evidence for the mineral scapolite
patially resolved reflectance spectra of Mars in the 2.2- to 2.4-μm spectral region were obtained in August 1988 using the NASA 3-m Infrared Telescope Facility. The spectra show weak absorption features due to Martian atmospheric carbon monoxide and a surface mineral. Both CO and the mineral absorptions are composed of overlapping narrow features, but in many locations, such as Hellas, Chryse, Ede
Authors
Roger N. Clark, Gregg A. Swayze, Robert B. Singer, James B. Pollack
Mineral resources of the Gibraltar Mountain and Planet Peak Wilderness Study Areas, La Paz County, Arizona
No abstract available.
Authors
R. G. Eppinger, J.A. Peterson, H. R. Blank, K.E. Livo, D. H. Knepper, J. A. Pitkin, J. E. Spencer, S. J. Reynolds, M. J. Grubensky, T.J. Kreidle, D.C. Scott
Shawangunk ore district, New York; geochemical and spectral data
No abstract available.
Authors
Jules D. Friedman, F.E. Mutschler, R. E. Zartman, Paul H. Briggs, G.A. Swayze, A.F. Thiesen
Spectral characteristics of chlorites and Mg‐serpentines using high‐resolution reflectance spectroscopy
The present laboratory study using high‐resolution reflectance spectroscopy (0.25–2.7 μm) focuses on two primary phyllosilicate groups, serpentines and chlorites. The results show that it is possible to spectrally distinguish between isochemical end‐members of the Mg‐rich serpentine group (chrysotile, antigorite, and lizardite) and to recognize spectral variations in chlorites as a function of Fe/
Authors
T. V. V. King, Roger N. Clark
Search for volatiles on icy satellites: I. Europa
New reflectance spectra have been obtained for both the leading and trailing sides of Europa, using the Cooled Grating Array Spectrometer (CGAS) of the NASA Infrared Telescope Facility (IRTF). The spectra are of higher precision than any yet obtained. Spectra of Europa's trailing side (central meridian longitude ≈300°) obtained in 1985 show two weak absorptions near 2.2 and 2.3 μm. Both of these f
Authors
R. H. Brown, D. P. Cruikshank, A. T. Tokunaga, R. G. Smith, Roger N. Clark
Europa: Characterization and interpretation of global spectral surface units
The Voyager global multispectral mosaic of the Galilean satellite Europa (T. V. Johnson, L. A. Soderblom, J. A. Mosher, G. E. Danielson, A. F. Cook, and P. Kupferman, 1983, J. Geophys. Res. 88, 5789–5805) was analyzed to map surface units with similar optical properties (T. B. McCord, M. L. Nelson, R. N. Clark, A. Meloy, W. Harrison, T. V. Johnson, D. L. Matson, J. A. Mosher, and L. Soderblom, 198
Authors
M. L. Nelson, T. B. McCord, Roger N. Clark, T. V. Johnson, D. L. Matson, J. A. Mosher, Laurence A. Soderblom
Reflectance spectroscopy: Quantitative analysis techniques for remote sensing applications
Several methods for the analysis of remotely sensed reflectance data are compared, including empirical methods and scattering theories, both of which are important for solving remote sensing problems. The concept of the photon mean optical path length and the implications for use in modeling reflectance spectra are presented. It is shown that the mean optical path length in a particulate surface i
Authors
Roger N. Clark, T. L. Roush
Spectral properties of ice‐particulate mixtures and implications for remote sensing: 1. Intimate mixtures
The spectral properties of water ice‐particulate mixtures are studied for the purpose of deriving the ice and particulate abundances from remotely obtained spectra (particulates referring to nonicy materials in the form of grains). Reflectance levels and ice absorption band depths are a complex function of the single scattering albedo of the particulates embedded in the ice. The ice absorption ban
Authors
Roger N. Clark, Paul G. Lucey