Mineralogy and distribution of critical elements in the Sn–W–Pb–Ag–Zn Huanuni deposit, Bolivia

The polymetallic Huanuni deposit, a world-class tin deposit, is part of the Bolivian tin belt. As a likely case for a “mesothermal” or transitional deposit between epithermal and porphyry Sn types (or shallow porphyry Sn), it represents a case that contributes significantly to the systematic study of the distribution of critical elements within the “family” of Bolivian tin deposits. In addition to Sn, Zn and Ag, further economic interest in the area resides in its potential in critical elements such as In, Ga and Ge. This paper provides the first systematic characterisation of the complex mineralogy and mineral chemistry of the Huanuni deposit with the twofold aim of identifying the mineral carriers of critical elements and endeavouring plausible metallogenic processes for the formation of this deposit, by means of a multi-methodological approach. With In concentrations consistently over 2000 ppm, the highest potential for relevant concentrations in this metal resides in widespread tin minerals (cassiterite and stannite) and sphalerite. Hypogene alteration assemblages are hardly developed due to the metasedimentary nature of host rocks, but the occurrence of potassium feldspar, schorl, pyrophyllite and dickite as vein material stand for potassic to phyllic or advanced argillic alteration assemblages and relatively high-temperature (and low pH) mineralising fluids. District-scale mineralogical zonation suggests a thermal zonation with decreasing temperatures from the central to the peripheral areas. A district-scale zonation has been also determined for d34SVCDT values, which range -7.2‰ to 0.2‰ (mostly -7‰ to -5‰) in the central area and -4.2‰ to 1.0‰ (mainly constrained between -2‰ and 1‰) in peripheral areas. Such values stand for magmatic and metasedimentary sources for sulfur, and their spatial zoning may be related to differential reactivity between mineralising fluids and host rocks, outwardly decreasing from the central to the peripheral areasPeer ReviewedPostprint (published version

Mineralogy and distribution of critical elements in the Sn–W–Pb–Ag–Zn Huanuni Deposit, Bolivia

The polymetallic Huanuni deposit, a world-class tin deposit, is part of the Bolivian tin belt. As a likely case for a “mesothermal” or transitional deposit between epithermal and porphyry Sn types (or shallow porphyry Sn), it represents a case that contributes significantly to the systematic study of the distribution of critical elements within the “family” of Bolivian tin deposits. In addition to Sn, Zn and Ag, further economic interest in the area resides in its potential in critical elements such as In, Ga and Ge. This paper provides the first systematic characterisation of the complex mineralogy and mineral chemistry of the Huanuni deposit with the twofold aim of identifying the mineral carriers of critical elements and endeavouring plausible metallogenic processes for the formation of this deposit, by means of a multi-methodological approach. With In concentrations consistently over 2000 ppm, the highest potential for relevant concentrations in this metal resides in widespread tin minerals (cassiterite and stannite) and sphalerite. Hypogene alteration assemblages are hardly developed due to the metasedimentary nature of host rocks, but the occurrence of potassium feldspar, schorl, pyrophyllite and dickite as vein material stand for potassic to phyllic or advanced argillic alteration assemblages and relatively high-temperature (and low pH) mineralising fluids. District-scale mineralogical zonation suggests a thermal zonation with decreasing temperatures from the central to the peripheral areas. A district-scale zonation has been also determined for δ34SVCDT values, which range −7.2‰ to 0.2‰ (mostly −7‰ to −5‰) in the central area and −4.2‰ to 1.0‰ (mainly constrained between −2‰ and 1‰) in peripheral areas. Such values stand for magmatic and metasedimentary sources for sulfur, and their spatial zoning may be related to differential reactivity between mineralising fluids and host rocks, outwardly decreasing from the central to the peripheral areas. Keywords: critical elements; indium; gallium; germanium; tin; silver; cerium; hydrothermal; bolivian tin bel

The San José-Itos mines, Oruro, Bolivia: structure and Ag-Sn mineralization

A new cartography of the veins and a detailed mineral sequence is provided for the Itos and San José mines, Oruro, Bolivia. The mineral sequence comprises an early stage with arsenopyrite, arsenian pyrite and cassiterite, followed by a stage with tin sulphosalts and Sn-rich sphalerite. In the latest stage, silver and lead sulphosalts formed along with galena, acanthite and sphalerite and minerals typical of advanced argillitic alteration (zunyite and minerals of the alunite supergroup). The occurrence of pseudocubic alunite with jamesonite and zunyite suggests that these minerals are not good indicators for a supergene vs. hydrothermal origin of the advanced argillitic hydrothermal alteration. Concentration of critical elements (In, Ge, Ga, Nb, Ta) in sphalerite, stannite and cassiterite is steadily low.Peer Reviewe

The San José-Itos mines, Oruro, Bolivia: structure and Ag-Sn mineralization

A new cartography of the veins and a detailed mineral sequence is provided for the Itos and San José mines, Oruro, Bolivia. The mineral sequence comprises an early stage with arsenopyrite, arsenian pyrite and cassiterite, followed by a stage with tin sulphosalts and Sn-rich sphalerite. In the latest stage, silver and lead sulphosalts formed along with galena, acanthite and sphalerite and minerals typical of advanced argillitic alteration (zunyite and minerals of the alunite supergroup). The occurrence of pseudocubic alunite with jamesonite and zunyite suggests that these minerals are not good indicators for a supergene vs. hydrothermal origin of the advanced argillitic hydrothermal alteration. Concentration of critical elements (In, Ge, Ga, Nb, Ta) in sphalerite, stannite and cassiterite is steadily low.Peer ReviewedPostprint (published version

Mineralogy and distribution of critical elements in the Sn–W–Pb–Ag–Zn Huanuni Deposit, Bolivia

The polymetallic Huanuni deposit, a world-class tin deposit, is part of the Bolivian tin belt. As a likely case for a “mesothermal” or transitional deposit between epithermal and porphyry Sn types (or shallow porphyry Sn), it represents a case that contributes significantly to the systematic study of the distribution of critical elements within the “family” of Bolivian tin deposits. In addition to Sn, Zn and Ag, further economic interest in the area resides in its potential in critical elements such as In, Ga and Ge. This paper provides the first systematic characterisation of the complex mineralogy and mineral chemistry of the Huanuni deposit with the twofold aim of identifying the mineral carriers of critical elements and endeavouring plausible metallogenic processes for the formation of this deposit, by means of a multi-methodological approach. With In concentrations consistently over 2000 ppm, the highest potential for relevant concentrations in this metal resides in widespread tin minerals (cassiterite and stannite) and sphalerite. Hypogene alteration assemblages are hardly developed due to the metasedimentary nature of host rocks, but the occurrence of potassium feldspar, schorl, pyrophyllite and dickite as vein material stand for potassic to phyllic or advanced argillic alteration assemblages and relatively high-temperature (and low pH) mineralising fluids. District-scale mineralogical zonation suggests a thermal zonation with decreasing temperatures from the central to the peripheral areas. A district-scale zonation has been also determined for δ34SVCDT values, which range −7.2‰ to 0.2‰ (mostly −7‰ to −5‰) in the central area and −4.2‰ to 1.0‰ (mainly constrained between −2‰ and 1‰) in peripheral areas. Such values stand for magmatic and metasedimentary sources for sulfur, and their spatial zoning may be related to differential reactivity between mineralising fluids and host rocks, outwardly decreasing from the central to the peripheral areas. Keywords: critical elements; indium; gallium; germanium; tin; silver; cerium; hydrothermal; bolivian tin beltThe polymetallic Huanuni deposit, a world-class tin deposit, is part of the Bolivian tin belt. As a likely case for a “mesothermal” or transitional deposit between epithermal and porphyry Sn types (or shallow porphyry Sn), it represents a case that contributes significantly to the systematic study of the distribution of critical elements within the “family” of Bolivian tin deposits. In addition to Sn, Zn and Ag, further economic interest in the area resides in its potential in critical elements such as In, Ga and Ge. This paper provides the first systematic characterisation of the complex mineralogy and mineral chemistry of the Huanuni deposit with the twofold aim of identifying the mineral carriers of critical elements and endeavouring plausible metallogenic processes for the formation of this deposit, by means of a multi-methodological approach. With In concentrations consistently over 2000 ppm, the highest potential for relevant concentrations in this metal resides in widespread tin minerals (cassiterite and stannite) and sphalerite. Hypogene alteration assemblages are hardly developed due to the metasedimentary nature of host rocks, but the occurrence of potassium feldspar, schorl, pyrophyllite and dickite as vein material stand for potassic to phyllic or advanced argillic alteration assemblages and relatively high-temperature (and low pH) mineralising fluids. District-scale mineralogical zonation suggests a thermal zonation with decreasing temperatures from the central to the peripheral areas. A district-scale zonation has been also determined for δ34SVCDT values, which range −7.2‰ to 0.2‰ (mostly −7‰ to −5‰) in the central area and −4.2‰ to 1.0‰ (mainly constrained between −2‰ and 1‰) in peripheral areas. Such values stand for magmatic and metasedimentary sources for sulfur, and their spatial zoning may be related to differential reactivity between mineralising fluids and host rocks, outwardly decreasing from the central to the peripheral areas. Keywords: critical elements; indium; gallium; germanium; tin; silver; cerium; hydrothermal; bolivian tin beltThe polymetallic Huanuni deposit, a world-class tin deposit, is part of the Bolivian tin belt. As a likely case for a “mesothermal” or transitional deposit between epithermal and porphyry Sn types (or shallow porphyry Sn), it represents a case that contributes significantly to the systematic study of the distribution of critical elements within the “family” of Bolivian tin deposits. In addition to Sn, Zn and Ag, further economic interest in the area resides in its potential in critical elements such as In, Ga and Ge. This paper provides the first systematic characterisation of the complex mineralogy and mineral chemistry of the Huanuni deposit with the twofold aim of identifying the mineral carriers of critical elements and endeavouring plausible metallogenic processes for the formation of this deposit, by means of a multi-methodological approach. With In concentrations consistently over 2000 ppm, the highest potential for relevant concentrations in this metal resides in widespread tin minerals (cassiterite and stannite) and sphalerite. Hypogene alteration assemblages are hardly developed due to the metasedimentary nature of host rocks, but the occurrence of potassium feldspar, schorl, pyrophyllite and dickite as vein material stand for potassic to phyllic or advanced argillic alteration assemblages and relatively high-temperature (and low pH) mineralising fluids. District-scale mineralogical zonation suggests a thermal zonation with decreasing temperatures from the central to the peripheral areas. A district-scale zonation has been also determined for δ34SVCDT values, which range −7.2‰ to 0.2‰ (mostly −7‰ to −5‰) in the central area and −4.2‰ to 1.0‰ (mainly constrained between −2‰ and 1‰) in peripheral areas. Such values stand for magmatic and metasedimentary sources for sulfur, and their spatial zoning may be related to differential reactivity between mineralising fluids and host rocks, outwardly decreasing from the central to the peripheral areas. Keywords: critical elements; indium; gallium; germanium; tin; silver; cerium; hydrothermal; bolivian tin bel

Huanuni, Bonanza and La Suerte Mines: mineralogy, geochemistry and structure

The polymetallic mineralization veins of the world class Huanuni district in Bolivia form a conspicuously intricate framework. Comprehensive study on the mineralogy of proximal and distal deposits indicates that In is preferably concentrated in sphalerite precipitated in a lower-temperature stage in the distal domain. Other strategic elements reported to concentrate in equivalent deposits (e.g. Ga, Ge, Nb, Ta), though, returned very low or no detectable concentrations. Mineral paragenesis and textures and sulfur isotopic data support a complex mineralization history that probably implied multi-episodic intrusive events.Peer Reviewe

Mineralogy and Distribution of Critical Elements in 1 the Sn-W-Pb-Ag-Zn Huanuni Deposit, Bolivia

The polymetallic Huanuni deposit, a world-class tin deposit, is part of the Bolivian tin belt. As a likely case for a "mesothermal" or transitional deposit between epithermal and porphyry Sn types (or shallow porphyry Sn), it represents a case that contributes significantly to the systematic study of the distribution of critical elements within the "family" of Bolivian tin deposits. In addition to Sn, Zn and Ag, further economic interest in the area resides in its potential in critical elements such as In, Ga and Ge. This paper provides the first systematic characterisation of the complex mineralogy and mineral chemistry of the Huanuni deposit with the twofold aim of identifying the mineral carriers of critical elements and endeavouring plausible metallogenic processes for the formation of this deposit, by means of a multi-methodological approach. With In concentrations consistently over 2000 ppm, the highest potential for relevant concentrations in this metal resides in widespread tin minerals (cassiterite and stannite) and sphalerite. Hypogene alteration assemblages are hardly developed due to the metasedimentary nature of host rocks, but the occurrence of potassium feldspar, schorl, pyrophyllite and dickite as vein material stand for potassic to phyllic or advanced argillic alteration assemblages and relatively high-temperature (and low pH) mineralising fluids. District-scale mineralogical zonation suggests a thermal zonation with decreasing temperatures from the central to the peripheral areas. A district-scale zonation has been also determined for δ34SVCDT values, which range −7.2 to 0.2 (mostly −7 to −5 ) in the central area and −4.2 to 1.0 (mainly constrained between −2 and 1 ) in peripheral areas. Such values stand for magmatic and metasedimentary sources for sulfur, and their spatial zoning may be related to differential reactivity between mineralising fluids and host rocks, outwardly decreasing from the central to the peripheral areas

Huanuni, Bonanza and La Suerte Mines: mineralogy, geochemistry and structure

The polymetallic mineralization veins of the world class Huanuni district in Bolivia form a conspicuously intricate framework. Comprehensive study on the mineralogy of proximal and distal deposits indicates that In is preferably concentrated in sphalerite precipitated in a lower-temperature stage in the distal domain. Other strategic elements reported to concentrate in equivalent deposits (e.g. Ga, Ge, Nb, Ta), though, returned very low or no detectable concentrations. Mineral paragenesis and textures and sulfur isotopic data support a complex mineralization history that probably implied multi-episodic intrusive events.Peer ReviewedPostprint (published version

The San José-Itos mines, Oruro, Bolivia: structure and Ag-Sn mineralization

A new cartography of the veins and a detailed mineral sequence is provided for the Itos and San José mines, Oruro, Bolivia. The mineral sequence comprises an early stage with arsenopyrite, arsenian pyrite and cassiterite, followed by a stage with tin sulphosalts and Sn-rich sphalerite. In the latest stage, silver and lead sulphosalts formed along with galena, acanthite and sphalerite and minerals typical of advanced argillitic alteration (zunyite and minerals of the alunite supergroup). The occurrence of pseudocubic alunite with jamesonite and zunyite suggests that these minerals are not good indicators for a supergene vs. hydrothermal origin of the advanced argillitic hydrothermal alteration. Concentration of critical elements (In, Ge, Ga, Nb, Ta) in sphalerite, stannite and cassiterite is steadily low.Peer Reviewe

Huanuni, Bonanza and La Suerte Mines: mineralogy, geochemistry and structure

The polymetallic mineralization veins of the world class Huanuni district in Bolivia form a conspicuously intricate framework. Comprehensive study on the mineralogy of proximal and distal deposits indicates that In is preferably concentrated in sphalerite precipitated in a lower-temperature stage in the distal domain. Other strategic elements reported to concentrate in equivalent deposits (e.g. Ga, Ge, Nb, Ta), though, returned very low or no detectable concentrations. Mineral paragenesis and textures and sulfur isotopic data support a complex mineralization history that probably implied multi-episodic intrusive events.Peer Reviewe