ed in the 
shown in 
dy ground 
| acquired, 
is for the 
esponding 
Traction of 
1e surface 
a slightly 
Xf shadow 
actions of 
1e to their 
ident sun 
with very 
d areas. If 
o the sur- 
contrast it 
¢ (Fig. 5), 
"tween the 
the slopes 
d fraction. 
on of sand 
d in most 
fractions. 
ig. 6, top) 
ments be- 
‘ers. Areas 
ear at the 
surfaces. 
NM. 
<-11% -11- <-2% -2-2% 
  
>2-11% > 11% masked 
Fig. 4: Fractions of the endmember SHADOW 
masked 0 - 20% 21-40% 
  
41 - 6096 61 - 8096 81 - 100% 
Fig. 5: Fractions of the endmember SAND 
Because sand is an individual endmember but occurs also 
In the stone pavement the obtained fractions can be ex- 
plained in two manners: (1) the endmembers occur as sep- 
erated areas or (ii) the stone pavement has a small 
coverage with flintstones. In the southeast of the image is 
à plateau that drains to the northeast. The drainage chan- 
nels are filled with sand and some flintstones. These areas 
show a large percentage of sand and a small fraction of 
Stone pavement. In the areas between the channels there is 
More or less dense stone pavement. The pixels in these 
areas are unmixed as sand and stone pavement and the 
fraction of stone pavement varies between 40 and 80%. 
229 
The nummulite-covered surfaces (Fig. 6, bottom) lie pre- 
dominantly east of the lake. These areas are pediments 
along the /nselberge covered by nummulites of the be- 
drock. With respect to this endmember the spectral unmix- 
ing is not unambigous and the areas could be nummulitic 
limestone without gypsum. The investigation of a spe- 
cimen from nummulitic limestone by x-ray diffraction 
showed that nummulitic limestone does not necessarily 
contain gypsum. 
Areas with a large fraction of gypsum containing num- 
mulitic limestone are rarely observed. 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996