Figure 15. Results are shown for retrieval and concentration
mapping of spectral endmembers for Mount Desert Island and Sands of
Forvie. This assumes that the spectra mix linearly, i.e., in a
checkerboard fashion. The three aerially important endmember spectra are
shown on the lower left and mapped using the same color coding on the
areas covered for the ROIs. The red spectrum and reddish colors mapped
on the ROIs correspond to bedrock regions mapped within the intricate
edges of the Mount Desert Island region and the southern part of the
Sands of Forvie. The northern part of the Sands of Forvie maps as a
mixture of bedrock contaminated areas and sand with an enhanced long
wavelength positive slope (i.e., purple areas). The southern area within
the sand sheet exhibits green colors typical of the mean for Sands of
Forvie.
The other two endmember spectra share similarities with the mean spectra
for the two sand deposits, one with a long wavelength rise (MDI, Figure
16) and the other with a broad and relatively deep ~2.2
µm absorption (SoF, Figure 17). Detailed analysis of the abundance map
shows the former spectrum is more abundant in the MDI dune and the
latter in the SoF sand sheet. The two spectra share a broad, not well
defined, ~1 µm spectral feature that is also evident in
the mean spectra for the two sand bodies. Note that endmember spectra
shown in these latter two figures were derived by taking the means of
the abundances for fractional proportions greater than 0.75 in each
case.