7
of the study area. According to Figure 6b, study area display
oxides as yellow. This combination helped corroborate areas
with oxides from the previous combination.
Band Ratio (BR) Analysis
This method is based on the spectral reflectance curve
that is characteristic of each material, and which enables
its identification and discrimination from other materials
(El-Arafy, 2024). Band ratios are a tool for detecting areas
with clay minerals concentrations (Table 1).
The band ratio 4/6 (Figure 7c) discriminated the
argillic to phyllic alteration with the representative min-
eral group: muscovite -illite – montmorillonite, which
extending mainly in the surroundings of the Paleogene
granodiorite intrusive bodies, the first one being located in
the Sapuc population center, another between Sullapucro
and Puñogon extending to the NE to the Parinteros
population center and the third in Chicos. The band ratio
4/5 (Figure 7d) is often employed for delineating the
advanced argillic alteration, which refers to a group of rep-
resentative minerals kaolinite -pyrophyllite – alunite. The
ratio shows the higher alteration zones distributed around
the granodioritic intrusive. Another concentration area of
advanced argilic alteration is around Lopez Pampa popula-
tion center. To highlight areas enriched with chlorite, epi-
dote and calcite minerals, an additional band ratio (5/8)
was employed (Figure 7b). This particular band ratio was
chosen to effectively identify and delineate the regions that
exhibit higher concentrations of these specific minerals.
The mineral associations are distinctly illustrated on the
map in green color, which has distributed with NW -SE
direction with respect to the Cospán location. Finally, the
2/1 Band Ratio data targets iron-oxide and ferrous bearing
minerals respectively as yellow tones (Figure 7b).
Figure 7. ASTER Band Ratio (a) propylitic alteration (b) iron oxide (c) argillic phyllic alteration (d) advanced argillic
alteration
of the study area. According to Figure 6b, study area display
oxides as yellow. This combination helped corroborate areas
with oxides from the previous combination.
Band Ratio (BR) Analysis
This method is based on the spectral reflectance curve
that is characteristic of each material, and which enables
its identification and discrimination from other materials
(El-Arafy, 2024). Band ratios are a tool for detecting areas
with clay minerals concentrations (Table 1).
The band ratio 4/6 (Figure 7c) discriminated the
argillic to phyllic alteration with the representative min-
eral group: muscovite -illite – montmorillonite, which
extending mainly in the surroundings of the Paleogene
granodiorite intrusive bodies, the first one being located in
the Sapuc population center, another between Sullapucro
and Puñogon extending to the NE to the Parinteros
population center and the third in Chicos. The band ratio
4/5 (Figure 7d) is often employed for delineating the
advanced argillic alteration, which refers to a group of rep-
resentative minerals kaolinite -pyrophyllite – alunite. The
ratio shows the higher alteration zones distributed around
the granodioritic intrusive. Another concentration area of
advanced argilic alteration is around Lopez Pampa popula-
tion center. To highlight areas enriched with chlorite, epi-
dote and calcite minerals, an additional band ratio (5/8)
was employed (Figure 7b). This particular band ratio was
chosen to effectively identify and delineate the regions that
exhibit higher concentrations of these specific minerals.
The mineral associations are distinctly illustrated on the
map in green color, which has distributed with NW -SE
direction with respect to the Cospán location. Finally, the
2/1 Band Ratio data targets iron-oxide and ferrous bearing
minerals respectively as yellow tones (Figure 7b).
Figure 7. ASTER Band Ratio (a) propylitic alteration (b) iron oxide (c) argillic phyllic alteration (d) advanced argillic
alteration