682 
ground water table. These depresión area still sup 
ply the water to underground during rainy season. 
Because of these phenomena, density of vegetation was 
employed for a denominator of paleo channel detection. 
5.2 Method for vegetation density survey 
Discussion to find the suitable method for vegetation 
density was done between MSS band ratio 7 / 5, 7 / 4 
and streched-ratioed colour composite image. Finally 
MSS ratio 7/4 was chosen as the most favourable 
technique to emphasize the density of vegetation in 
this area. 
mdst appropriate weight was given, which was, land 
coverage : depth : paleo channel = 3 • 10 : 10. 
The result of evaluation is shown on figure 9* 
The mesh units which evaluated the highest potential 
are shown in black and the second potential area is 
in dots. The research and prospection for uranium 
are taken place in the mining concession, the squ 
are in the figure. And some of good result of the 
prospection were reported from that area. Most of 
the highly scored mesh units are distributed in the 
mining square. From such view point it can be sum- 
merized that the result of this evaluation suggest 
the area where have favorable environment for urani 
um deposit beneath there. 
10 
20 
30 
n /•> ^Seepage 
i ry n 
a 
/^MS® 
done, sand- 
7 / // N ” 
, 1 Basement rocks / A 
w 'ff 
■<S^V\- 'Dt t 
Sedimentary ' 
" nocks_ •. ' ' N 
' 1 ~ Ground A Basement rocks 
wcjter V \ 
vege 
tation 
dense(high) 
barren 
dense(short) 
middle 
barren, non veget. 
geo 
logy 
basement & 
little sand cov 
thick sand 
lian) 
aeo- 
fine sand to 
silty material 
coarse sand 
sand(coarse-fine), 
silt 
topo 
graphy 
gentle si. 
undulation 
active sand dune 
small depression 
depression,big& 
good sucsession 
sand is stable, 
highly undulated 
many small linear 
depression 
Figure 7. The relation between vegetation, geology and topography 
5.3 Relation between vegetation and paleo channel 
distribution 
The distribution of dense vegetation zone is shown on 
figure 8 (a), of which pattern is like of the river 
channel. However, there are not developed any rivers 
on the surface at present time. With using the bore 
hole data the depth of the basement rock was analysed, 
which is shown on figure 8 (b). 
The basement rocks form like valley shape and the 
paleo channel is developed in that valley. There are 
very similar pattern of development between vegeta 
tion and paleo channel, which 
can be observed in map (a), 
(b). 
Generally the depressional 
area is densely vegetated. 
Occasionally the lineaments 
and the sinkholes are deve 
loped in there, which seem 
to supply ground water to 
the paleo channel even at 
present time. 
6 EVALUATION 
Land coverage, depth thick 
ness distribution of sedi 
mentary rocks and the paleo 
channel analysed by Landsat 
imagery are employed for the 
factors to evaluate the area 
where are the suitable en 
vironment of the uranium de 
posit . 
For the evaluation, we 
scored these items with cer 
tain weight in each mesh, 
1 Km x 1 Kim. After several 
time of try and error the 
7 CONCLUSION 
Landsat data analysis can be used for the possible 
area evaluation of sedimentary uranium deposit. 
However, still some technical problems are remained 
on the each procedure. For instance, some part of 
laterite was not identified from the basement rock, 
the physical relation between surface phenomena and 
geological structure is not completely made clear 
yet, and so on. These ploblems can be solved in the 
furture to study in comaparison with other data, 
such as field survey, geophysical prospecting,boring 
test, etc. 
Figure 8. Comparison between pattern of vegetation distribution (a) and (b) 
morphology of basement rock 
123°E 
\ 
V 
□ 
Figure 9* 
deposit 
REFERENCES 
Childers, 
taceous 
Colorado 
Floyd, F.S 
tation Y 
Missallati 
Simatler 
Landsat 
Remote s 
Smith, A.F 
ing of I 
ceedings 
process! 
remote s 
Vincent, F 
-process