1
25-096
Use of Aster Satellite Images to Identify Ore-Bearing
Hydrothermal Alteration Zones Within Asuncion and
Cospan Districts
Mayra Casas Azañero
SME, UNC, Cajamarca, PE
Quispe Mamani
Crispín Zenón, UNC, Cajamarca, PE
ABSTRACT
The research is located within Asuncion and Cospan dis-
tricts, which according to their geological features in con-
trast with previous studies pointing out Au, Mo and Pb
anomalies create an environment of prospective interest.
The objective is to use ASTER Satellite Images to iden-
tify ore-bearing hydrothermal alteration zones. To do this,
processing techniques such as the combination of bands
by RGB 943 and 461, band ratio 4/6, 4/5, 5/8 and 2/1
to identify advanced argillic, argillic to phyllic and propy-
litic alterations. In addition, indices defined by Ninomiya
were used as a third technique in order to reinforce the data
obtained from the previous techniques. The results in the
study area are confirmed by the SAM spectral mapping
technique using spectral signatures from the USGS library.
Identifying kaolinite, alunite and pyrophyllite, assemblages
of the advanced argillic alteration. Concluding in 3 areas
of interest with the band ratios, 5 areas with the Ninomiya
indexes and 9 areas validated with SAM, which were con-
trasted in 13 areas of prospective interest with well-marked
argillic alteration.
Keywords: Aster, remote sensing, hydrothermal alteration,
spectral bands, mineral mapping
INTRODUCTION
Over the past two decades, the development of spectral
remote sensing technologies has significantly advanced
capabilities for mapping mineral system- related altera-
tion, particularly with the applications in searching mineral
resources or geological information of an area. Multispectral
and hyperspectral remote sensing technologies, due to their
expansive spatial coverage and rich spectral information,
have emerged as potent tools for mapping mineral spatial
distribution. Among these, Aster data, that are a staple in
multispectral remote sensing geology (Geng Zhang et al.,
2024). The ASTER multispectral satellite has 14 high-reso-
lution bands divided into three subsystems: three bands of
visible and near infrared (VNIR), six bands of shortwave
infrared (SWIR) and five bands thermal infrared (TIR)
which through mathematics and combinations of bands,
it is possible to discriminate the lithology, minerals and
alterations on the earth’s surface (Vargas,2015). In that
context, ASTER Shortwave infrared (SWIR) bands with
the wavelength of ASTER SWIR bands between 1.65 and
2.43 μm has a good potential for mapping a hydrothermal
alteration minerals such as alunite, pyrophyllite, kaolinite,
illite–muscovite–sericite, and carbonate (Azizi, Tarverdi
and Akbarpour, 2010).
In addition, taking into account that the Cajamarca
region is home to important mining deposits such as
Yanacocha, La Zanja, Tantahuatay, Cerro Corona, Conga,
Michiquillay, Galeno, Shahuindo and that the research area
according to its geological, tectonic, structural and metallo-
genic context in contrast with previous studies carried out
by INGEMMET, which indicate the presence of Au, Mo
and Pb anomalies (Chira et al., 2007), they create a favor-
able environment of interest for the prospecting of pos-
sible new mineral deposits. In summary, Cajamarca region
stands as an ideal region for mineralization remote sensing
exploration. To this end, this study proposed the Use of
ASTER Satellite Images to identify ore-bearing hydrother-
mal alteration zones within Asuncion and Cospan districts.
This investigation is justified in prospecting new areas in
25-096
Use of Aster Satellite Images to Identify Ore-Bearing
Hydrothermal Alteration Zones Within Asuncion and
Cospan Districts
Mayra Casas Azañero
SME, UNC, Cajamarca, PE
Quispe Mamani
Crispín Zenón, UNC, Cajamarca, PE
ABSTRACT
The research is located within Asuncion and Cospan dis-
tricts, which according to their geological features in con-
trast with previous studies pointing out Au, Mo and Pb
anomalies create an environment of prospective interest.
The objective is to use ASTER Satellite Images to iden-
tify ore-bearing hydrothermal alteration zones. To do this,
processing techniques such as the combination of bands
by RGB 943 and 461, band ratio 4/6, 4/5, 5/8 and 2/1
to identify advanced argillic, argillic to phyllic and propy-
litic alterations. In addition, indices defined by Ninomiya
were used as a third technique in order to reinforce the data
obtained from the previous techniques. The results in the
study area are confirmed by the SAM spectral mapping
technique using spectral signatures from the USGS library.
Identifying kaolinite, alunite and pyrophyllite, assemblages
of the advanced argillic alteration. Concluding in 3 areas
of interest with the band ratios, 5 areas with the Ninomiya
indexes and 9 areas validated with SAM, which were con-
trasted in 13 areas of prospective interest with well-marked
argillic alteration.
Keywords: Aster, remote sensing, hydrothermal alteration,
spectral bands, mineral mapping
INTRODUCTION
Over the past two decades, the development of spectral
remote sensing technologies has significantly advanced
capabilities for mapping mineral system- related altera-
tion, particularly with the applications in searching mineral
resources or geological information of an area. Multispectral
and hyperspectral remote sensing technologies, due to their
expansive spatial coverage and rich spectral information,
have emerged as potent tools for mapping mineral spatial
distribution. Among these, Aster data, that are a staple in
multispectral remote sensing geology (Geng Zhang et al.,
2024). The ASTER multispectral satellite has 14 high-reso-
lution bands divided into three subsystems: three bands of
visible and near infrared (VNIR), six bands of shortwave
infrared (SWIR) and five bands thermal infrared (TIR)
which through mathematics and combinations of bands,
it is possible to discriminate the lithology, minerals and
alterations on the earth’s surface (Vargas,2015). In that
context, ASTER Shortwave infrared (SWIR) bands with
the wavelength of ASTER SWIR bands between 1.65 and
2.43 μm has a good potential for mapping a hydrothermal
alteration minerals such as alunite, pyrophyllite, kaolinite,
illite–muscovite–sericite, and carbonate (Azizi, Tarverdi
and Akbarpour, 2010).
In addition, taking into account that the Cajamarca
region is home to important mining deposits such as
Yanacocha, La Zanja, Tantahuatay, Cerro Corona, Conga,
Michiquillay, Galeno, Shahuindo and that the research area
according to its geological, tectonic, structural and metallo-
genic context in contrast with previous studies carried out
by INGEMMET, which indicate the presence of Au, Mo
and Pb anomalies (Chira et al., 2007), they create a favor-
able environment of interest for the prospecting of pos-
sible new mineral deposits. In summary, Cajamarca region
stands as an ideal region for mineralization remote sensing
exploration. To this end, this study proposed the Use of
ASTER Satellite Images to identify ore-bearing hydrother-
mal alteration zones within Asuncion and Cospan districts.
This investigation is justified in prospecting new areas in