GRSG 34th Conference 2023

Title: Mineral exploration using EnMAP hyperspectral data: Case studies from four different deposit types

Author: Saeid Asadzadeh

Mining new resources remains essential to meet the increasing demands for raw materials and adhere to sustainability standards. Among the methodologies that can significantly contribute to the discovery of new resources of base metals and critical minerals is spaceborne remote sensing technology, including the EnMAP imaging instrument. To demonstrate this, we conducted an analysis of EnMAP hyperspectral data over four distinct deposit types located in arid regions of the world. These deposits encompass a porphyry copper and a Volcanogenic Massive Sulfide (VMS) deposit in Iran (Dehaj and Taknar), a Mississippi Valley Type (MVT) Pb-Zn mineralization in Yemen (Jabali), and a Rare Earth Element (REE)-bearing carbonatite in the USA (Mountain Pass).

In each of these sites, the Level 2A orthorectified surface reflectance data of EnMAP was processed by applying the polynomial fitting technique aimed to parametrize the diagnostic absorption features of target minerals, including wavelength minimum, depth, width, area, and asymmetry. In the case of the porphyry copper deposit, the high-temperature core of the system, which had eluded detection during field studies and drilling due to intense hydrothermal activities, was effectively unveiled by the white mica composition map.

The presence of Al-rich white mica in this map highlighted the central high-temperature cores. White mica chemistry also proved invaluable in mapping the fluid migration pathways and deposition centers of the VMS deposit, in addition to highlighting new concealed areas with potential for similar mineralization. For MVT deposit, a reduction in carbonate contents, a transition in mineralogy from calcite to dolomite, and an increase in kaolinite abundance and crystallinity were observed to be associated with Pb-Zn mineralization. Over the carbonatite deposit, EnMAP successfully resolved the characteristic doublet absorption features of REE-bearing bastnaesite in the 750 nm range, as well as the carbonate-related feature at 2340 nm using VNIR and SWIR bands, respectively. Our study indicated that EnMAP outperforms previous generations of multi- and hyperspectral datasets when it comes to sensing alteration mineralogy and detecting REE signatures. These capabilities can be effectively used to target new mineral resources in arid to semi-arid regions across the globe.

Mining new resources remains essential to meet the increasing demands for raw materials and adhere to sustainability standards. Among the methodologies that can significantly contribute to the discovery of new resources of base metals and critical minerals is spaceborne remote sensing technology, including the EnMAP imaging instrument. To demonstrate this, we conducted an analysis of EnMAP hyperspectral data over four distinct deposit types located in arid regions of the world. These deposits encompass a porphyry copper and a Volcanogenic Massive Sulfide (VMS) deposit in Iran (Dehaj and Taknar), a Mississippi Valley Type (MVT) Pb-Zn mineralization in Yemen (Jabali), and a Rare Earth Element (REE)-bearing carbonatite in the USA (Mountain Pass). ]

In each of these sites, the Level 2A orthorectified surface reflectance data of EnMAP was processed by applying the polynomial fitting technique aimed to parametrize the diagnostic absorption features of target minerals, including wavelength minimum, depth, width, area, and asymmetry. In the case of the porphyry copper deposit, the high-temperature core of the system, which had eluded detection during field studies and drilling due to intense hydrothermal activities, was effectively unveiled by the white mica composition map. The presence of Al-rich white mica in this map highlighted the central high-temperature cores. White mica chemistry also proved invaluable in mapping the fluid migration pathways and deposition centers of the VMS deposit, in addition to highlighting new concealed areas with potential for similar mineralization.

For MVT deposit, a reduction in carbonate contents, a transition in mineralogy from calcite to dolomite, and an increase in kaolinite abundance and crystallinity were observed to be associated with Pb-Zn mineralization. Over the carbonatite deposit, EnMAP successfully resolved the characteristic doublet absorption features of REE-bearing bastnaesite in the 750 nm range, as well as the carbonate-related feature at 2340 nm using VNIR and SWIR bands, respectively. Our study indicated that EnMAP outperforms previous generations of multi- and hyperspectral datasets when it comes to sensing alteration mineralogy and detecting REE signatures. These capabilities can be effectively used to target new mineral resources in arid to semi-arid regions across the globe.