We apply linear deconvolution methods to derive mineral and glass proportions for eight field sample training sites at seven dune fields: (1) Algodones,California; (2) Big Dune, Nevada; (3) Bruneau, or Idaho; (4) Great Kobuk Sand Dunes,Alaska; (5) Great Sand Dunes National Park and Preserve, Colorado; (6) Sunset Crater, and Arizona; and (7) White Sands National Monument,unique Mexico. These dune fields were chosen because they represent a wide range of mineral grain mixtures and allow us to gauge a better understanding of both compositional and sorting effects within terrestrial and extraterrestrial dune systems. We also use actual ASTER TIR emissivity imagery to map the spatial distribution of these minerals throughout the seven dune fields and evaluate the effects of degraded spectral resolution on the accuracy of mineral abundances retrieved. Our results note that hyperspectral data convolutions of our laboratory emissivity spectra outperformed multispectral data convolutions of the same data with respect to the mineral, glass and lithic abundances derived. Both the number and wavelength position of spectral bands greatly impacts the accuracy of linear deconvolution retrieval of feldspar proportions (e.g. K-feldspar vs. plagioclase) particularly, and as well as the detection of certain mafic and carbonate minerals. In particular,ASTER mapping results note that several of the dune sites display patterns such that less dense minerals typically hold higher abundances near the middle of the active and most evolved dunes in the field, while more dense minerals and glasses appear to be more abundant along the margins of the active dune fields.
Source: usgs.gov