Connotea
CiteULike
del.ico.us
BibSonomyAbstract
Near-infrared optical constants of pyroxene as a function of iron and calcium content
Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa, Honolulu, Hawaii, USA
Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa, Honolulu, Hawaii, USA
Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, Hawaii, USA
Natural Sciences Division, Pasadena City College, Pasadena, California, USA
We derive the imaginary coefficient of the complex index of refraction (k) from reflectance spectra of 30 pyroxenes using the method of Lucey (1998). We apply the modified Gaussian model of Sunshine et al. (1990) to these k spectra to obtain two continuum parameters and nine Gaussian parameters that describe the 1, 2, and 1.2 μm crystal field absorptions. This method takes advantage of the redundancy in the data and minimizes the number of free parameters, resulting in a compact expression of optical constants that is less susceptible to noise in the data and contamination from terrestrial weathering. Multiple regression results indicate that the continuum and Gaussian parameters are well predicted by pyroxene FeO and CaO contents; thus a complete k spectrum for pyroxene can be derived from arbitrary FeO and CaO concentrations. The uncertainty is highest for the 1.2 μm M1 crystal field absorption in both orthopyroxene and clinopyroxene. These k spectra can be used with radiative transfer theory to produce model reflectance spectra of particulate silicate surfaces at different viewing geometries, particle sizes, levels of space weathering, and mixtures with other minerals.
Received 29 July 2006; accepted 30 November 2006; published 17 May 2007.
Citation: (2007), Near-infrared optical constants of pyroxene as a function of iron and calcium content, J. Geophys. Res., 112, E05009, doi:10.1029/2006JE002802.
Cited By