11
CONCLUSIONS
The use of Satellite Images allowed a qualitative estima-
tion of various types of hydrothermal alteration, defined
mainly based on the mineralogical assemblages proposed by
El-Desoky et al. (2021) and the metallogenic environment
of the evaluated area, making it possible to determine zones
of Hydrothermal Alterations in the districts of La Asunción
and Cospán, with a greater predominance of advanced
Argilic and Argilic to Phylic Alteration and with a lesser
predominance of Propylitic Alteration.
With the geological-structural mapping it has been
possible to contrast that the halos of argillic, phyllic and
propylitic alteration coincide with zones of great deforma-
tion of the strata and faults of the trans- Andean trend,
which are responsible for the emplacement of the intrusive
bodies of granodiorite, these being the generators of the
zoning of hydrothermal alterations.
By applying spectral techniques on the ASTER satellite
image, it was possible to determine with the combination of
bands a general environment for clays and oxides, having 3
characteristic zones with said minerals in the research area
with the band ratios 4/6, 4/5, 5/8 and 2/1 it was possible
to carry out a first zoning of the hydrothermal alterations
and delimit 3 zones of prospective interest and with the
technique related to the Ninomiya indices OHla, OHlb,
CLI, ALI and KLI, it was possible to reinforce the zoning of
those alteration zones with respect to the previous process-
ing techniques, managing to identify 5 areas of prospective
interest.
The SAM (Spectral Angle Mapper) spectral mapping
technique using spectral signatures from the United States
Geological Survey (USGS) library was useful for the valida-
tion of zones with the presence of hydrothermal alteration
minerals, obtained with the spectral techniques of band
combination, band ratios and Ninomiya indices, allowing
to better notice the refinement of the alteration halos based
on the typical mineralogical assemblies of each hydrother-
mal alteration. It was possible to validate thirteen areas of
prospective interest with well-marked argillic alteration.
RECOMMENDATIONS
To obtain more accurate data, a more detailed study should
be carried out using the TERRASPEC spectrometer, which
allows comparing the spectral signature of a satellite image
with the spectral signature in situ.
REFERENCES
[1] Caiza, K. (2018). “Estimation of Hydrothermal
Alteration Zones by Interpretation of Aster-Type
Satellite Images and Use of Terraspec Equipment in
the Eastern Zone of Cerro de Pasco”. [Thesis Eng.
Geol., Central University of Ecuador]. Institutional
Repository -Central University of Ecuador.
[2] Clark, R.N. (1999). “Spectroscopy of rocks and min-
erals, and principles of spectroscopy”. Manual of
Remote Sensing, 3, Wiley &Sons Inc., New York,
pp. 3–58.
[3] El-Arafy, R.A. Abd El Salam, H.F. Shaheen, M.A.
Abdel A.E. (2024). ”Integrative mapping of radioac-
tive and alteration zones in Um Had plutons, Egypt:
Using Landsat 9, ASTER imagery, and airborne geo-
physical data”. Journal of African Earth Sciences.
216 (105313). ISSN 1464-343X. DOI: 10.1016
/j.jafrearsci.2024.1053.
[4] El-Desoky, H., Abdel, A., Soliman, N. y Heikal, M.
(2021). “Mapping hydrothermal alteration zones
using ASTER images in the Arabian–Nubian Shield:
A case study of the northwestern Allaqi District,
South Eastern Desert, Egypt. Journal of Asian
Earth Sciences”. Elsevier, 5(2021): pp. 1–16. DOI:
10.1016/j.jaesx.2021.100060.
[5] Geng Zhang, Zhifang Zhao, Xinle Zhang, Xiatao Wu,
Yangfan Zheng, Lunxin Feng, Ziqi Huang (2024).
“Comprehensive Multi- Source remote sensing data
integration for enhanced mineralization alteration
extraction and geological structure interpretation in
the Lala region of Sichuan Province”. Ore.
[6] Geology Reviews. 168 (106032): pp. 1–4. ISSN 0169-
1368. DOI: 10.1016/j.oregeorev.2024.106 032.
[7] H. Azizi, M.A. Tarverdi, A. Akbarpour, (2010).
“Extraction of hydrothermal alterations from ASTER
SWIR data from east Zanjan, northern Iran”.
Advances in Space Research. 46: pp. 99–109. ISSN
0273-1177. DOI: 10.1016/j.asr.2010.03.014.
[8] Kruse, F.A. Lefkoff, A.B. Boardman, J.W.
Heidebrecht, K.B. Shapiro, A.T. Barloon, P.J.
Goetz, A.F.H. (1993). “The spectral image processing
system (SIPS)—interactive visualization and analysis
of imaging spectrometer data,” Remote Sensing of
Environment, 44: pp. 145–163, ISSN 0034-4257,
DOI: 10.1016/0034- 4257(93)90013-N.
[9] Ninomiya, Y. (2003). “A Stabilized Vegetation Index
and Several Mineralogic Indices Defined for ASTER
VNIR and SWIR Data”. Geological Survey of Japan.
DOI: 10.1109/IGARSS.2003.1294172.
[10] Rodriguez, G. (2008). “Determination of
Hydrothermal Alteration Zones Using Aster Images,
Western Cajamarca”. [Thesis Eng. Geol., National
University of Saint Anthony the Abbot of Cusco].
CONCLUSIONS
The use of Satellite Images allowed a qualitative estima-
tion of various types of hydrothermal alteration, defined
mainly based on the mineralogical assemblages proposed by
El-Desoky et al. (2021) and the metallogenic environment
of the evaluated area, making it possible to determine zones
of Hydrothermal Alterations in the districts of La Asunción
and Cospán, with a greater predominance of advanced
Argilic and Argilic to Phylic Alteration and with a lesser
predominance of Propylitic Alteration.
With the geological-structural mapping it has been
possible to contrast that the halos of argillic, phyllic and
propylitic alteration coincide with zones of great deforma-
tion of the strata and faults of the trans- Andean trend,
which are responsible for the emplacement of the intrusive
bodies of granodiorite, these being the generators of the
zoning of hydrothermal alterations.
By applying spectral techniques on the ASTER satellite
image, it was possible to determine with the combination of
bands a general environment for clays and oxides, having 3
characteristic zones with said minerals in the research area
with the band ratios 4/6, 4/5, 5/8 and 2/1 it was possible
to carry out a first zoning of the hydrothermal alterations
and delimit 3 zones of prospective interest and with the
technique related to the Ninomiya indices OHla, OHlb,
CLI, ALI and KLI, it was possible to reinforce the zoning of
those alteration zones with respect to the previous process-
ing techniques, managing to identify 5 areas of prospective
interest.
The SAM (Spectral Angle Mapper) spectral mapping
technique using spectral signatures from the United States
Geological Survey (USGS) library was useful for the valida-
tion of zones with the presence of hydrothermal alteration
minerals, obtained with the spectral techniques of band
combination, band ratios and Ninomiya indices, allowing
to better notice the refinement of the alteration halos based
on the typical mineralogical assemblies of each hydrother-
mal alteration. It was possible to validate thirteen areas of
prospective interest with well-marked argillic alteration.
RECOMMENDATIONS
To obtain more accurate data, a more detailed study should
be carried out using the TERRASPEC spectrometer, which
allows comparing the spectral signature of a satellite image
with the spectral signature in situ.
REFERENCES
[1] Caiza, K. (2018). “Estimation of Hydrothermal
Alteration Zones by Interpretation of Aster-Type
Satellite Images and Use of Terraspec Equipment in
the Eastern Zone of Cerro de Pasco”. [Thesis Eng.
Geol., Central University of Ecuador]. Institutional
Repository -Central University of Ecuador.
[2] Clark, R.N. (1999). “Spectroscopy of rocks and min-
erals, and principles of spectroscopy”. Manual of
Remote Sensing, 3, Wiley &Sons Inc., New York,
pp. 3–58.
[3] El-Arafy, R.A. Abd El Salam, H.F. Shaheen, M.A.
Abdel A.E. (2024). ”Integrative mapping of radioac-
tive and alteration zones in Um Had plutons, Egypt:
Using Landsat 9, ASTER imagery, and airborne geo-
physical data”. Journal of African Earth Sciences.
216 (105313). ISSN 1464-343X. DOI: 10.1016
/j.jafrearsci.2024.1053.
[4] El-Desoky, H., Abdel, A., Soliman, N. y Heikal, M.
(2021). “Mapping hydrothermal alteration zones
using ASTER images in the Arabian–Nubian Shield:
A case study of the northwestern Allaqi District,
South Eastern Desert, Egypt. Journal of Asian
Earth Sciences”. Elsevier, 5(2021): pp. 1–16. DOI:
10.1016/j.jaesx.2021.100060.
[5] Geng Zhang, Zhifang Zhao, Xinle Zhang, Xiatao Wu,
Yangfan Zheng, Lunxin Feng, Ziqi Huang (2024).
“Comprehensive Multi- Source remote sensing data
integration for enhanced mineralization alteration
extraction and geological structure interpretation in
the Lala region of Sichuan Province”. Ore.
[6] Geology Reviews. 168 (106032): pp. 1–4. ISSN 0169-
1368. DOI: 10.1016/j.oregeorev.2024.106 032.
[7] H. Azizi, M.A. Tarverdi, A. Akbarpour, (2010).
“Extraction of hydrothermal alterations from ASTER
SWIR data from east Zanjan, northern Iran”.
Advances in Space Research. 46: pp. 99–109. ISSN
0273-1177. DOI: 10.1016/j.asr.2010.03.014.
[8] Kruse, F.A. Lefkoff, A.B. Boardman, J.W.
Heidebrecht, K.B. Shapiro, A.T. Barloon, P.J.
Goetz, A.F.H. (1993). “The spectral image processing
system (SIPS)—interactive visualization and analysis
of imaging spectrometer data,” Remote Sensing of
Environment, 44: pp. 145–163, ISSN 0034-4257,
DOI: 10.1016/0034- 4257(93)90013-N.
[9] Ninomiya, Y. (2003). “A Stabilized Vegetation Index
and Several Mineralogic Indices Defined for ASTER
VNIR and SWIR Data”. Geological Survey of Japan.
DOI: 10.1109/IGARSS.2003.1294172.
[10] Rodriguez, G. (2008). “Determination of
Hydrothermal Alteration Zones Using Aster Images,
Western Cajamarca”. [Thesis Eng. Geol., National
University of Saint Anthony the Abbot of Cusco].