In: Wagner W., Székely, B. (eds.): ISPRS TC VII Symposium - 100 Years ISPRS, Vienna, Austria, July 5-7, 2010, IAPRS, Vol. XXXVIII, Part 7B 
261 
2004). Herein this study, thermal reflectance properties of 
ultramafic rocks rich in olivine minerals will be estimated. 
Figure 4. Simplified stratigraphic section of the study area. 
Lower Cretaceous Eldivan ophiolite, which is given 
in green (dark) color, overlays Triassic basement 
units, and overlaid by Tertiary sedimentary 
sequences. 
2.1 VNIR-SWIR Band Ratio 
According to the spectral properties of mafic minerals given in 
figure 1A, characteristic wavelengths can be correlated with 
ASTER VNIR and SWIR bands. 
There are higher reflection responses in ASTER bands 2, 5 and 
8, absorption in bands 1, 3 and 6 for olivine mineral while only a 
broad absorption in band 3 and a reflection in band 1 can be 
noticeable for pyroxene minerals in the SWIR region of 
electromagnetic spectrum. Serpentine, the alteration product of 
those minerals, has also distinguishing absorptions in bands 2, 7 
and 8 and reflection in bands 3 and 6. The band ratios, 2/3, 
2/3*1/3 for olivine mineral and 6/8 and 6/7 for serpentine 
mineral were developed. 
2.2 TIR Band Algorithms 
The pyroxenes exhibit visible reflections in ASTER bands 11 and 
12 according to the given figure IB. Despite, olivine mineral has 
higher reflection in band 13 and lower in bands 10, 11 and 12. 
While showing similarities, the olivine mineral is higher in bands 
12 and 14 compared to the alteration product of olivine and 
pyroxenes, serpentine. 
As the olivine-peridotite or dunite, composed of mainly olivine 
and additionally pyroxenes and less silica, is compared with 
ASTER bands in figure 5, band 13 is highly reflected while the 
bands 11, 12 has absorption and 14 is relatively low reflected. 
The absorption properties of ASTER bands 11 and 14 for 
olivine display similarities to quartz mineral. However, the 
difference between those two spectra is noticeable in bands 12 
and 13. This difference was also recorded as a result of a change 
in silicate content within the igneous rocks varies from felsic 
through mafic to ultramafic by some researchers (Ninomiya and 
Matsunaga, 1997, 2002, 2003; Hook et al, 2005). 
While the higher reflection in band 13 for dunite and 
neighbouring bands 12 and 14 are taking under consideration in 
figure 5, the band ratios of 12/13 and 14/13 is achieved. To use 
opposite band ratios instead of usual ones is the cause of the 
energy emitted from the surface materials in thermal region. The 
higher reflection in the spectrum corresponds to the low 
emissivity. Since above ratios, (12*14) / (13 2 ) is obtained. 
Figure 5. The spectral pattern comparison of olivine-peridotite 
(dunite) and quartz with corresponding ASTER 
bands 
The formula, (14/13) / (13/12) 3 , is developed by considering the 
ratio 14/13 for olivine and pyroxene mineral with comparing to 
the ratio 13/12 for silicate content. The exponential parameter 
(herein 3) is a number that is used for decreasing the effect of 
silica content within the rocks. The number used here, 3, is 
chosen for giving the best result. 
2.3 Results and Discussions 
The VNIR-SWIR band ratios developed to extract the 
ultramafic units have mostly not efficient, except serpentine band 
ratio 6/8. On the contrary, the better results were attained with 
thermal infrared (TIR) region for detection of lithology like 
olivine-peridotite occurrences. 
The results of VNIR-SWIR band ratios, 2/3 for olivine and 6/8 
for serpentine minerals are given in Figure 6. Besides the 
matching localities for olivine resultant image, it is also possible 
to observe the areas unmatched. The serpentine band ratio 6/8 
(or even 6/7) can mostly be correlated with the serpentinized 
ultramafic rock units. Besides the results of the olivine band 
ratio 2/3 correlating well with the ophiolite formations inside, it 
has widely wrong results outside the ophiolitic formation 
boundaries. 
The olivine rich ultramafic rock, olivine-peridotite or dunite was 
noticeably extracted within the ophiolitic melange formation 
given in simplified geological map (figure 3, 7A, 7B) with 
distinct boundaries by using the spectral properties of target 
ultramafic rocks. Additionally, the ground truth studies were 
conducted to 15 localities of matched or unmatched with either 
analyses results or geological map units. 13 of 15 collected