Comparison of Different Algorithms to Map Hydrothermal Alteration Zones Using ASTER Remote Sensing Data for Polymetallic Vein-Type Ore Exploration: Toroud–Chahshirin Magmatic Belt (TCMB), North Iran

Abstract

Polymetallic vein-type ores are important sources of precious metal and a principal type of orebody for various base-metals. In this research, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) remote sensing data were used for mapping hydrothermal alteration zones associated with epithermal polymetallic vein-type mineralization in the Toroud–Chahshirin Magmatic Belt (TCMB), North of Iran. The TCMB is the largest known goldfield and base metals province in the central-north of Iran. Propylitic, phyllic, argillic, and advanced argillic alteration and silicification zones are typically associated with Au-Cu, Ag, and/or Pb-Zn mineralization in the TCMB. Specialized image processing techniques, namely Selective Principal Component Analysis (SPCA), Band Ratio Matrix Transformation (BRMT), Spectral Angle Mapper (SAM) and Mixture Tuned Matched Filtering (MTMF) were implemented and compared to map hydrothermal alteration minerals at the pixel and sub-pixel levels. Subtle differences between altered and non-altered rocks and hydrothermal alteration mineral assemblages were detected and mapped in the study area. The SPCA and BRMT spectral transformation algorithms discriminated the propylitic, phyllic, argillic and advanced argillic alteration and silicification zones as well as lithological units. The SAM and MTMF spectral mapping algorithms detected spectrally dominated mineral groups such as muscovite/montmorillonite/illite, hematite/jarosite, and chlorite/epidote/calcite mineral assemblages, systematically. Comprehensive fieldwork and laboratory analysis, including X-ray diffraction (XRD), petrographic study, and spectroscopy were conducted in the study area for verifying the remote sensing outputs. Results indicate several high potential zones of epithermal polymetallic vein-type mineralization in the northeastern and southwestern parts of the study area, which can be considered for future systematic exploration programs. The approach used in this research has great implications for the exploration of epithermal polymetallic vein-type mineralization in other base metals provinces in Iran and semi-arid regions around the world.

Mapping Listvenite Occurrences in the Damage Zones of Northern Victoria Land, Antarctica Using ASTER Satellite Remote Sensing Data

“…Listvenite, a carbonate-silica-dominated rock that forms as a result of CO 2 -and K-metasomatism of ultramafic/mafic rocks, represents a key indicator for the occurrence of ore mineralizations along shear zones or major tectonic boundaries [20][21][22][23][138][139][140]. The ability to map hydrothermal alteration mineral and listvenites using spectral bands of ASTER satellite remote sensing data has been successfully established in many parts of the world [6][7][8][9][10][11][12][27][28][29]31,43]. Features in the spectra of lithological units are dependent upon their constituent minerals and intensities.…”

“…Hydrothermal/metasomatic alteration mineral assemblages are one of the significant indicators for ore mineralizations in the damage zones of lithotectonic units in orogenic systems [1][2][3]. They can be detected and mapped by the application of multispectral satellite remote sensing data [4][5][6][7][8][9][10][11][12]. Listvenite is a metasomatic rock composed of variable amounts of quartz, magnesite, ankerite, dolomite, sericite, calcite, talc and sulfide minerals.…”

“…Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) multispectral remote sensing satellite data provide appropriate spatial, spectral and radiometric resolutions suitable for mapping hydrothermal/metasomatic alteration mineral assemblages [6][7][8][9][10][11][12][27][28][29][30][31]. Iron oxide/hydroxide, hydroxyl-bearing and carbonate mineral groups present diagnostic spectral absorption features due to electronic processes of transition elements (Fe 2+ , Fe 3+ and REE) and vibrational processes of fundamental absorptions of Al-OH, Mg-OH, Fe-OH, Si-OH, CO 3 , NH 4 and SO 4 groups in the visible and near infrared (VNIR) and shortwave infrared (SWIR) regions [32][33][34][35].…”

Identification and characterization of hydrothermally altered minerals using surface and space-based reflectance spectroscopy, in parts of south-eastern Rajasthan, India

“…High spectral resolution of hyperspectral sensors makes it an ideal complementary and confirming tool alongside traditional multi-spectral and field-based methods for mineral exploration [3]. Therefore, reflectance and emission spectroscopy in visible-to-near-infra-red and mid-infra-red have globally been used as an important tool for mineral characterization and exploration [8,20,22,26,32,39,44]. Data collected by imaging spectrometer using geometrically coherent spectral measurements facilitate quantitative and qualitative identification and mapping, thereby allowing a more detailed characterization of the spatial mineralogical heterogeneity using mixture analysis technique [21,[50][51][52][53].With the availability of more sophisticated and high-resolution spectrometers, the field of imaging spectroscopy from space, air or field has grown in terms of technical capability and application potential in geological mapping and mineral exploration [12,13,19,27,33,35,36,43,45,54,56].…”

Landsat-8, Advanced Spaceborne Thermal Emission and Reflection Radiometer, and WorldView-3 Multispectral Satellite Imagery for Prospecting Copper-Gold Mineralization in the Northeastern Inglefield Mobile Belt (IMB), Northwest Greenland

“…Many regions in the High Arctic remain poorly investigated for mineral exploration due to cold climate environments and remoteness, especially the northern part of Greenland containing Zn-Pb and Cu-Au mineralization [1][2][3]. The visible and near-infrared (VNIR), shortwave infrared (SWIR) and thermal infrared (TIR) bands of multispectral remote sensing data contain unprecedented spectral and spatial capabilities for detecting hydrothermal alteration minerals and lithological units associated with a variety of ore mineralization [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Numerous investigations successfully used Landsat data series, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), and the Advanced Land Imager (ALI) multispectral data with moderate spatial resolution for the reconnaissance stages of mineral exploration around the world [23][24][25][26][27][28][29].…”