Remote Sensing - Dune Worlds: How Windblown Sand Shapes Planetary Landscapes - page 214

Fig. 18.11 The near-infrared
provides many more diagnostic
spectral features. Olivine has a
wide band at just above
1 micron, and gypsum has a very
deep band at 1.9 microns. These
data (and those in Fig. 18.10 ) are
from the USGS Spectral Library
Fig. 18.12 A CRISM image
region of sand dunes surrounding
the Martian north polar cap
acquired on October 1, 2006 near
80.0N latitude, 240.7E
longitude. It covers an area about
12 km (7.5 miles) square. At the
center of the image, the spatial
resolution is as good as 20 m
(65 ft)/pixel. The image was
taken in 544 colors covering
0.36-3.92 lm: the image at right
shows the strength of an
absorption band at 1900 nm
wavelength, which indicates the
relative abundance of the sulfate
mineral gypsum