Pub Date : 2025-01-24DOI: 10.1016/j.oregeorev.2025.106457
Dominic Raisch, Sebastian Staude, Gregor Markl
The interaction of sulfide melt with silicate melt or partially molten country rock produces a wide variety of textures that can appear similar to net-textured sulfides which originate from accumulation of sulfide melt within the host intrusion and therefore occur in different areas within the orebody. This similarity in textures can cause misidentification during exploration and could cause confusion and wrong financial decisions. Therefore, these semi-massive sulfide textures were investigated in detail and partly redefined. They comprise (1) net, (2) infiltration, (3) disaggregation, and (4) emulsion textures.
Net-textured sulfides form by sulfide melt infiltrating into existing silicate cumulate thereby replacing interstitial silicate melt resulting in a continuous matrix of sulfides enclosing magmatic cumulate silicates. Silicates like pyroxenes display the highest XMg values of all textures and are occasionally sector-zoned. Contrary, infiltration, disaggregation and emulsion textures form by the infiltration of sulfide melt into the country rock by partial melting. Infiltration textures form during the initial process and are therefore defined by refractory fragments of country rock with abundant peritectic phases with additional minor amounts of anatectic melt enclosed in a continuous matrix of magmatic sulfides. Disaggregation textures represent the refractory end-stage and are defined as single grains or clusters of high thermal stability silicate crystals derived from the country rock suspended in magmatic sulfides. Macroscopically, this texture can look identical to net-textured sulfides, but can be distinguished by the lack of magmatic silicates, such as olivine, by elevated Ni and Mn contents plus lower XMg values of pyroxenes and by different luminescence colours of plagioclase in the disaggregation texture. The newly formed buoyant and immiscible silicate melt is less dense than the sulfide melt resulting in upward counter migration and the formation of the emulsion texture when frozen in. Depending on the ratio of the two melts, this texture may appear as a fine-grained droplet emulsion or as a connected bicontinuous emulsion, but both types have the same defining characteristics, such as high levels of eutectic intergrowths, newly formed skeletal and euhedral silicate crystals, and they contain high levels of hydrous silicates.
The newly crystallized pyroxenes in the emulsion texture exhibit the highest Ni and Mn contents and lowest XMg values compared to all other textures, and in addition, plagioclase again shows different luminescence colours. Where the newly formed silicate melt is trapped, it can form pegmatoidal pockets displaying the same features as the emulsion textures, but with less sulfides.
{"title":"Revisiting semi-massive Sulfides: Textures of sulfide-silicate interactions in magmatic sulfide deposits","authors":"Dominic Raisch, Sebastian Staude, Gregor Markl","doi":"10.1016/j.oregeorev.2025.106457","DOIUrl":"10.1016/j.oregeorev.2025.106457","url":null,"abstract":"<div><div>The interaction of sulfide melt with silicate melt or partially molten country rock produces a wide variety of textures that can appear similar to net-textured sulfides which originate from accumulation of sulfide melt within the host intrusion and therefore occur in different areas within the orebody. This similarity in textures can cause misidentification during exploration and could cause confusion and wrong financial decisions. Therefore, these semi-massive sulfide textures were investigated in detail and partly redefined. They comprise (1) net, (2) infiltration, (3) disaggregation, and (4) emulsion textures.</div><div>Net-textured sulfides form by sulfide melt infiltrating into existing silicate cumulate thereby replacing interstitial silicate melt resulting in a continuous matrix of sulfides enclosing magmatic cumulate silicates. Silicates like pyroxenes display the highest X<sub>Mg</sub> values of all textures and are occasionally sector-zoned. Contrary, infiltration, disaggregation and emulsion textures form by the infiltration of sulfide melt into the country rock by partial melting. Infiltration textures form during the initial process and are therefore defined by refractory fragments of country rock with abundant peritectic phases with additional minor amounts of anatectic melt enclosed in a continuous matrix of magmatic sulfides. Disaggregation textures represent the refractory end-stage and are defined as single grains or clusters of high thermal stability silicate crystals derived from the country rock suspended in magmatic sulfides. Macroscopically, this texture can look identical to net-textured sulfides, but can be distinguished by the lack of magmatic silicates, such as olivine, by elevated Ni and Mn contents plus lower X<sub>Mg</sub> values of pyroxenes and by different luminescence colours of plagioclase in the disaggregation texture. The newly formed buoyant and immiscible silicate melt is less dense than the sulfide melt resulting in upward counter migration and the formation of the emulsion texture when frozen in. Depending on the ratio of the two melts, this texture may appear as a fine-grained droplet emulsion or as a connected bicontinuous emulsion, but both types have the same defining characteristics, such as high levels of eutectic intergrowths, newly formed skeletal and euhedral silicate crystals, and they contain high levels of hydrous silicates.</div><div>The newly crystallized pyroxenes in the emulsion texture exhibit the highest Ni and Mn contents and lowest X<sub>Mg</sub> values compared to all other textures, and in addition, plagioclase again shows different luminescence colours. Where the newly formed silicate melt is trapped, it can form pegmatoidal pockets displaying the same features as the emulsion textures, but with less sulfides.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"178 ","pages":"Article 106457"},"PeriodicalIF":3.2,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-22DOI: 10.1016/j.oregeorev.2025.106456
Fei Teng , Kang Yan , Ke Yang , Leon Bagas , Yongbao Gao , Liyong Wei , Yuxiang Teng , Haomin Guo , Yuanhe Tang , Guoying Li
The Huayagou gold deposit, situated at Longnan-Fengtai mineral field (LMF) within the Western Qinling Orogen (WQO) of central China, is a newly identified deposit, representative of major deposits within Gansu section that hold significant geological and economic value. Its geological similarities to major deposits in Fengtai district underscore its importance for advancing regional mining exploration and metallogenic studies. However, the lack of robust geochronological data and detailed geological characterization hampers our comprehensive understanding of the deposit’s genesis and regional metallogenic significance. To address this, research was carried out, involving detailed geological and mineralogical examination of ore samples from the Huayagou and subsequently robust chronology. Two distinct stages of mineralisation have been identified based on mineral association. The U-Pb dating of hydrothermal apatite that is closely associated with mineralisation yielded a 207Pb-corrected age of 205 ± 23 Ma (MSWD = 0.4) on Tera-Wasserburg concordia diagram, interpreted as the timing for primary mineralisation event. Microscopic and geochemical analyses confirmed the hydrothermal origin of apatite, which intergrows with arsenopyrite and gold, providing a reliable chronological framework for the deposit’s formation. These findings align with the 230–210 Ma mineralisation period established for major deposits in the LMF, such as Pangjiahe, Baguamiao, and Shuangwang. The ca. 248 Ma and ca. 163 Ma ages obtained from in situ Rb-Sr of sericite correspond to two rapid regional cooling events, possibly caused by uplifting and related metamorphism. Integrating these results into the regional geological context, we classify the Huayagou deposit as an orogenic gold deposit. This deposit, like others in the LMF, supports the spatial zoning model correlating uplift rates and erosion intensities with the distribution of epizonal, mesozonal, and hypozonal orogenic deposits across the western, central, and eastern regions of the field, respectively. The Late Triassic period in the WQO, characterized by the transition from subduction to collision to post-collision extension of the Paleo-Tethys Ocean, was a key phase for tectonic-magmatic activity and large-scale, multi-stage ore formation. Our findings reinforce this metallogenic framework and suggest significant potential for further gold exploration in the region.
{"title":"Geological characteristics and geochronology of the Huayagou Au deposit, Western Qinling: Implication for regional ore genesis","authors":"Fei Teng , Kang Yan , Ke Yang , Leon Bagas , Yongbao Gao , Liyong Wei , Yuxiang Teng , Haomin Guo , Yuanhe Tang , Guoying Li","doi":"10.1016/j.oregeorev.2025.106456","DOIUrl":"10.1016/j.oregeorev.2025.106456","url":null,"abstract":"<div><div>The Huayagou gold deposit, situated at Longnan-Fengtai mineral field (LMF) within the Western Qinling Orogen (WQO) of central China, is a newly identified deposit, representative of major deposits within Gansu section that hold significant geological and economic value. Its geological similarities to major deposits in Fengtai district underscore its importance for advancing regional mining exploration and metallogenic studies. However, the lack of robust geochronological data and detailed geological characterization hampers our comprehensive understanding of the deposit’s genesis and regional metallogenic significance. To address this, research was carried out, involving detailed geological and mineralogical examination of ore samples from the Huayagou and subsequently robust chronology. Two distinct stages of mineralisation have been identified based on mineral association. The U-Pb dating of hydrothermal apatite that is closely associated with mineralisation yielded a <sup>207</sup>Pb-corrected age of 205 ± 23 Ma (MSWD = 0.4) on Tera-Wasserburg concordia diagram, interpreted as the timing for primary mineralisation event. Microscopic and geochemical analyses confirmed the hydrothermal origin of apatite, which intergrows with arsenopyrite and gold, providing a reliable chronological framework for the deposit’s formation. These findings align with the 230–210 Ma mineralisation period established for major deposits in the LMF, such as Pangjiahe, Baguamiao, and Shuangwang. The ca. 248 Ma and ca. 163 Ma ages obtained from in situ Rb-Sr of sericite correspond to two rapid regional cooling events, possibly caused by uplifting and related metamorphism. Integrating these results into the regional geological context, we classify the Huayagou deposit as an orogenic gold deposit. This deposit, like others in the LMF, supports the spatial zoning model correlating uplift rates and erosion intensities with the distribution of epizonal, mesozonal, and hypozonal orogenic deposits across the western, central, and eastern regions of the field, respectively. The Late Triassic period in the WQO, characterized by the transition from subduction to collision to post-collision extension of the Paleo-Tethys Ocean, was a key phase for tectonic-magmatic activity and large-scale, multi-stage ore formation. Our findings reinforce this metallogenic framework and suggest significant potential for further gold exploration in the region.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"178 ","pages":"Article 106456"},"PeriodicalIF":3.2,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143148780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-20DOI: 10.1016/j.oregeorev.2025.106463
Christopher J.M. Lawley , Duane C. Petts , Well-Shen Lee , Yamila Cajal , Carlos Carrasco-Godoy , Ian H. Campbell , Joanna Dlugosz , Kyle P. Larson , Dany Savard , Ingrid Kjarsgaard , Bram I. van Straaten
Porphyry deposits are major sources of copper, gold, molybdenum, and silver globally. However, the potential for critical raw materials (CRM) to be mined as by-products (e.g., antimony, bismuth, platinum group elements, and tellurium) at these deposits is poorly understood. Herein we present results from a lithogeochemical survey (n = 331), detailed mineralogy, and trace element mapping to characterize the concentrations of CRM and their deportment within the Golden Triangle, northwest British Columbia, Canada. We demonstrate that the host rocks to porphyry copper-gold (i.e., Galore Creek, Copper Canyon, KSM, Dok, Yeti, and Burgundy) and epithermal gold-silver (i.e., Brucejack) deposits were derived from oxidized and water-rich parental melts that suppressed sulphide crystallization, resulting in the pre-enrichment of CRM relative to other arc rocks globally. The structural juxtaposition, local thickening, and preservation of these prospective source rocks is likely one of the factors contributing to the mineral district’s exceptional gold and CRM endowment. Multiple analytical methods (e.g., aqua-regia, four-acid, fusion) for the same samples further demonstrate that the highest Bi (39 ppm), Pd (460 ppb), Sb (375 ppm), and Te (15 ppm) concentrations are associated with sulphide and/or other non-resistate minerals within the most hydrothermally altered samples. Detailed mineralogy and trace element mapping by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) reveals that CRM within the Golden Triangle are hosted by at least 58 different minerals. We apply these results to estimate the contained CRM at the Galore Creek and KSM deposits and to discuss their potential to be recovered as by-products. Lithogeochemical results are also applied to predict the mineral potential of different igneous suites within the Golden Triangle based on their CRM concentrations.
{"title":"Critical raw material potential of porphyry copper-gold deposits in the Golden Triangle, northwest British Columbia, Canada","authors":"Christopher J.M. Lawley , Duane C. Petts , Well-Shen Lee , Yamila Cajal , Carlos Carrasco-Godoy , Ian H. Campbell , Joanna Dlugosz , Kyle P. Larson , Dany Savard , Ingrid Kjarsgaard , Bram I. van Straaten","doi":"10.1016/j.oregeorev.2025.106463","DOIUrl":"10.1016/j.oregeorev.2025.106463","url":null,"abstract":"<div><div>Porphyry deposits are major sources of copper, gold, molybdenum, and silver globally. However, the potential for critical raw materials (CRM) to be mined as by-products (e.g., antimony, bismuth, platinum group elements, and tellurium) at these deposits is poorly understood. Herein we present results from a lithogeochemical survey (n = 331), detailed mineralogy, and trace element mapping to characterize the concentrations of CRM and their deportment within the Golden Triangle, northwest British Columbia, Canada. We demonstrate that the host rocks to porphyry copper-gold (i.e., Galore Creek, Copper Canyon, KSM, Dok, Yeti, and Burgundy) and epithermal gold-silver (i.e., Brucejack) deposits were derived from oxidized and water-rich parental melts that suppressed sulphide crystallization, resulting in the pre-enrichment of CRM relative to other arc rocks globally. The structural juxtaposition, local thickening, and preservation of these prospective source rocks is likely one of the factors contributing to the mineral district’s exceptional gold and CRM endowment. Multiple analytical methods (e.g., aqua-regia, four-acid, fusion) for the same samples further demonstrate that the highest Bi (39 ppm), Pd (460 ppb), Sb (375 ppm), and Te (15 ppm) concentrations are associated with sulphide and/or other non-resistate minerals within the most hydrothermally altered samples. Detailed mineralogy and trace element mapping by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) reveals that CRM within the Golden Triangle are hosted by at least 58 different minerals. We apply these results to estimate the contained CRM at the Galore Creek and KSM deposits and to discuss their potential to be recovered as by-products. Lithogeochemical results are also applied to predict the mineral potential of different igneous suites within the Golden Triangle based on their CRM concentrations.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"178 ","pages":"Article 106463"},"PeriodicalIF":3.2,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-19DOI: 10.1016/j.oregeorev.2025.106471
Ming Zhang , Jun Tan , Yanyan Zhao , Ziqing Yan , Shushan Zhao , Changyong Lu , Xiaoyang Liu , Yu Zhang
<div><div>Jiaodong Peninsula is home to the largest gold district in China, encompassing significant deposits within the Qixia-Penglai Gold Belt, renowned for the presence of visible gold. Nonetheless, the timing of deposit formation and the intricate processes of gold transport and precipitation mechanisms remain subjects of ongoing debate. To deepen the comprehension of these processes, sericite geochronological analysis, fluid inclusion micro-thermometry, H-O isotope students, and trace element pyrite geochemical analysis were undertaken at the Ankou deposit. <sup>40</sup>Ar/<sup>39</sup>Ar dating of three representative deposits in the Ankou-Heilangou ore field limits the mineralization to a tight age range of 118–120 Ma. Our study identifies four distinct stages of ore-forming, namely the pyrite-quartz stage (Stage 1), the quartz-pyrite stage (Stage 2), the quartz-polymetallic sulfide stage (Stage 3), and the quartz-calcite stage (Stage 4). The fluid inclusion homogenization temperatures range from 227 to 372 °C, 217 to 334 °C, 168 to 306 °C, and 106 to 265 °C, respectively. Salinities recorded during these stages are predominantly below 10 wt% NaCl equivalent; H-O isotope analysis of the main metallogenic stage (Stages 2 and 3) yielded δ<sup>18</sup>O<sub>H2O</sub> values ranging from +5.2 ‰ to +7.2 ‰ and +4.5 ‰ to +7.4 ‰, alongside δD<sub>SMOW</sub> ranges from −94.6 ‰ to −83.0 ‰ and −95.8 ‰ to −87.7 ‰, respectively. Meanwhile, these results support a model of mineralization originating by incremental mixing of meteoric and magmatically-sourced fluids, with gold precipitation linked to fluid boiling and immiscibility reactions. From micro-textural observations, backscattered electron (BSE) imaging, and geochemical analysis, ten sub-generations of pyrite were identified. Stage 1 pyrites (Py1-1, Py1-2, and Py1-3) tracing records changes in As and Au concentrations, mineralogical capture, and hydrothermal alteration processes. Stage 2 pyrites (Py2-1, Py2-2, Py2-3a, and Py2-3b) indicate an obvious cored-mantle-edge structure, and the outer edge of the pyrite exhibits oscillatory BSE-bright and -dark reactions rims linked to similar changes in Au and As concentrations, consistent with pressure fluctuations and fluid immiscibility. Furthermore, Stage 3 pyrite (Py3-1, Py3-2, and Py3-3) exhibits comparable BSE-bright and dark zonation patterns, reflecting Au and As variability triggered by fluid pulsing. These findings reveal that the ore-forming fluids within the Ankou gold deposit exhibit characteristics identical to those found in mesothermal deposits. The ore-forming fluids are primarily derived from magmatic water, with a small amount of meteoric water added in the process of the main metallogenic stages. Furthermore, gold was probably transported at Ankou in the form of <span><math><mrow><mi>A</mi><mi>u</mi><msubsup><mrow><mo>(</mo><mi>H</mi><mi>S</mi><mo>)</mo></mrow><mrow><mn>2</mn></mrow><mo>-</mo></msubsup></mrow></math></span> complexes
{"title":"Metallogenic mechanism of Ankou gold deposit in the Qixia-Penglai Gold Belt, Jiaodong Peninsula, China: Constraints from sericite Ar-Ar geochronology, H-O isotope, and in-situ trace element of pyrite","authors":"Ming Zhang , Jun Tan , Yanyan Zhao , Ziqing Yan , Shushan Zhao , Changyong Lu , Xiaoyang Liu , Yu Zhang","doi":"10.1016/j.oregeorev.2025.106471","DOIUrl":"10.1016/j.oregeorev.2025.106471","url":null,"abstract":"<div><div>Jiaodong Peninsula is home to the largest gold district in China, encompassing significant deposits within the Qixia-Penglai Gold Belt, renowned for the presence of visible gold. Nonetheless, the timing of deposit formation and the intricate processes of gold transport and precipitation mechanisms remain subjects of ongoing debate. To deepen the comprehension of these processes, sericite geochronological analysis, fluid inclusion micro-thermometry, H-O isotope students, and trace element pyrite geochemical analysis were undertaken at the Ankou deposit. <sup>40</sup>Ar/<sup>39</sup>Ar dating of three representative deposits in the Ankou-Heilangou ore field limits the mineralization to a tight age range of 118–120 Ma. Our study identifies four distinct stages of ore-forming, namely the pyrite-quartz stage (Stage 1), the quartz-pyrite stage (Stage 2), the quartz-polymetallic sulfide stage (Stage 3), and the quartz-calcite stage (Stage 4). The fluid inclusion homogenization temperatures range from 227 to 372 °C, 217 to 334 °C, 168 to 306 °C, and 106 to 265 °C, respectively. Salinities recorded during these stages are predominantly below 10 wt% NaCl equivalent; H-O isotope analysis of the main metallogenic stage (Stages 2 and 3) yielded δ<sup>18</sup>O<sub>H2O</sub> values ranging from +5.2 ‰ to +7.2 ‰ and +4.5 ‰ to +7.4 ‰, alongside δD<sub>SMOW</sub> ranges from −94.6 ‰ to −83.0 ‰ and −95.8 ‰ to −87.7 ‰, respectively. Meanwhile, these results support a model of mineralization originating by incremental mixing of meteoric and magmatically-sourced fluids, with gold precipitation linked to fluid boiling and immiscibility reactions. From micro-textural observations, backscattered electron (BSE) imaging, and geochemical analysis, ten sub-generations of pyrite were identified. Stage 1 pyrites (Py1-1, Py1-2, and Py1-3) tracing records changes in As and Au concentrations, mineralogical capture, and hydrothermal alteration processes. Stage 2 pyrites (Py2-1, Py2-2, Py2-3a, and Py2-3b) indicate an obvious cored-mantle-edge structure, and the outer edge of the pyrite exhibits oscillatory BSE-bright and -dark reactions rims linked to similar changes in Au and As concentrations, consistent with pressure fluctuations and fluid immiscibility. Furthermore, Stage 3 pyrite (Py3-1, Py3-2, and Py3-3) exhibits comparable BSE-bright and dark zonation patterns, reflecting Au and As variability triggered by fluid pulsing. These findings reveal that the ore-forming fluids within the Ankou gold deposit exhibit characteristics identical to those found in mesothermal deposits. The ore-forming fluids are primarily derived from magmatic water, with a small amount of meteoric water added in the process of the main metallogenic stages. Furthermore, gold was probably transported at Ankou in the form of <span><math><mrow><mi>A</mi><mi>u</mi><msubsup><mrow><mo>(</mo><mi>H</mi><mi>S</mi><mo>)</mo></mrow><mrow><mn>2</mn></mrow><mo>-</mo></msubsup></mrow></math></span> complexes","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"178 ","pages":"Article 106471"},"PeriodicalIF":3.2,"publicationDate":"2025-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143289837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.oregeorev.2025.106444
Jiu-Yi Wang , Liang Zhang , Li-Qiang Yang , Si-Chen Sun , Rong-Hua Li , Xue Gao , Paul Olin , Lei Shu , Qi-Bin Zhang , Xiao-Gang Chen , Lei Gao
The representative Huangjindong gold deposit with >80 t gold is controlled by the NNE-NE-trending Changsha-Pingjiang Fault, in the central Jiangnan Orogen, south China. Petrography, microthermometry and Laser Raman studies of fluid inclusions in quartz from the deposit show that (1) two types of fluid inclusions are present (Type 1 H2O-CO2 inclusions, Type 2 aqueous inclusions) in all three stages. The homogenization temperature decreased through time with 330 ∼ 192 °C, 253 ∼ 180 °C and 232 ∼ 161 °C for the three stages, respectively; (2) The initial ore-forming fluids belong to CO2-NaCl-H2O system, with H2O-CO2-CH4-bearing volatile gas, medium to high temperature (192 ∼ 330 °C), low-salinity (2.2 ∼ 8.9 wt% NaCl eqv.) and low density (0.745 ∼ 0.988 g/cm3). In-situ LA-ICP-MS trace element analysis of quartz of different stages show that the syn-gold auriferous quartz has higher trace element contents and mineral inclusions compared to the pre- and post-gold barren quartz. The initial deeply-sourced fluids migrated to the EW-NWW-trending third-order faults related to the EW-NWW-trending anticlines and synclines, forming large-scale milky barren quartz veins during the pre-gold stage at ≥330 ∼ 192 °C. During the mineralization, the characteristics of disseminated, quartz-sulfide veins and brecciate ores, phase separation characteristics showed by fluid inclusions, and the high content of trace elements indicate that fluid immiscibility and fluid-wallrock interaction triggered the instability of and precipitation of Au, forming gray auriferous quartz-polysulfides veins that overprinted the early barren quartz veins at ≥253 ∼ 180 °C. Minor white quartz-carbonate veins formed under relatively lower temperature of ≥232 ∼ 161 °C and pressure marking the end of the ore-forming hydrothermal event.
{"title":"Ore-forming fluid evolution and gold precipitation mechanism at Huangjindong gold deposit, southern China: Insights from fluid inclusions and trace elements in quartz","authors":"Jiu-Yi Wang , Liang Zhang , Li-Qiang Yang , Si-Chen Sun , Rong-Hua Li , Xue Gao , Paul Olin , Lei Shu , Qi-Bin Zhang , Xiao-Gang Chen , Lei Gao","doi":"10.1016/j.oregeorev.2025.106444","DOIUrl":"10.1016/j.oregeorev.2025.106444","url":null,"abstract":"<div><div>The representative Huangjindong gold deposit with >80 t gold is controlled by the NNE-NE-trending Changsha-Pingjiang Fault, in the central Jiangnan Orogen, south China. Petrography, microthermometry and Laser Raman studies of fluid inclusions in quartz from the deposit show that (1) two types of fluid inclusions are present (Type 1 H<sub>2</sub>O-CO<sub>2</sub> inclusions, Type 2 aqueous inclusions) in all three stages. The homogenization temperature decreased through time with 330 ∼ 192 °C, 253 ∼ 180 °C and 232 ∼ 161 °C for the three stages, respectively; (2) The initial ore-forming fluids belong to CO<sub>2</sub>-NaCl-H<sub>2</sub>O system, with H<sub>2</sub>O-CO<sub>2</sub>-CH<sub>4</sub>-bearing volatile gas, medium to high temperature (192 ∼ 330 °C), low-salinity (2.2 ∼ 8.9 wt% NaCl eqv.) and low density (0.745 ∼ 0.988 g/cm<sup>3</sup>). <em>In-situ</em> LA-ICP-MS trace element analysis of quartz of different stages show that the <em>syn</em>-gold auriferous quartz has higher trace element contents and mineral inclusions compared to the pre- and post-gold barren quartz. The initial deeply-sourced fluids migrated to the EW-NWW-trending third-order faults related to the EW-NWW-trending anticlines and synclines, forming large-scale milky barren quartz veins during the pre-gold stage at ≥330 ∼ 192 °C. During the mineralization, the characteristics of disseminated, quartz-sulfide veins and brecciate ores, phase separation characteristics showed by fluid inclusions, and the high content of trace elements indicate that fluid immiscibility and fluid-wallrock interaction triggered the instability of <span><math><mrow><msubsup><mrow><mi>A</mi><mi>u</mi><mo>(</mo><mi>H</mi><mi>S</mi><mo>)</mo></mrow><mrow><mn>2</mn></mrow><mo>-</mo></msubsup></mrow></math></span> and precipitation of Au, forming gray auriferous quartz-polysulfides veins that overprinted the early barren quartz veins at ≥253 ∼ 180 °C. Minor white quartz-carbonate veins formed under relatively lower temperature of ≥232 ∼ 161 °C and pressure marking the end of the ore-forming hydrothermal event.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"178 ","pages":"Article 106444"},"PeriodicalIF":3.2,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143148386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.oregeorev.2025.106443
Ziang Ye , Lingling Gao , Yunpeng Li , Chuan Chen , Fang Xia , Shunda Li , Yasheng Zhu
The discovery of the Lamasu-Saibo copper deposit in the western Tianshan region of Xinjiang, China, has filled a significant gap of large porphyry-skarn-type copper deposits in the region. This discovery holds great significance for prospecting and exploring efforts in the western Tianshan region. The spatial distribution of the Lamasu-Saibo copper deposit is controlled by fault zones and the intrusion of medium-acidic granitic rocks, and its formation is closely related to magmatic activity, making it a crucial prospecting indicator for mining areas. To identify the spatial distribution of ore-controlling fault zones and intermediate-acid granitic intrusive rocks, a combination of high-precision magnetic surveys and magnetotelluric (MT) soundings based on regional and geological characteristics were used. Both high-precision magnetic surveys and MT soundings indicated the presence of deep-seated, medium-acidic rocks within the mining area. At present, the Chagankol fault system and some east–west trending faults are believed to be the primary ore-controlling structures in this mining area. These structures serve as pathways for deep-seated magmas and ore-forming fluids, creating a favorable environment for mineralization. Analysis of the ore-forming model of this deposit with respect to its geological-geophysical characteristics served as the basis for a prospective model for porphyry-skarn-type copper deposits in the Lamasu-Saibo area. Based on this prospective model and existing drilling data, the spatial distribution of the main orebodies in the deep underground mining area was determined. In summary, this study identified three anomalous zones. Zones I and II, on the basis of available exploration results, located within 1000 m of the subsurface, exhibit promising prospects for mineral exploration, while Zone III also showed good exploration potential. These findings provide valuable guidance for future prospecting efforts in the Lamasu-Saibo copper deposit and serve as a reference for the exploration of porphyry-skarn-type copper deposits in the region.
{"title":"Prospecting model and deep mineralization predictions for the Lamasu-Saibo copper deposit based on combined geological and geophysical exploration information","authors":"Ziang Ye , Lingling Gao , Yunpeng Li , Chuan Chen , Fang Xia , Shunda Li , Yasheng Zhu","doi":"10.1016/j.oregeorev.2025.106443","DOIUrl":"10.1016/j.oregeorev.2025.106443","url":null,"abstract":"<div><div>The discovery of the Lamasu-Saibo copper deposit in the western Tianshan region of Xinjiang, China, has filled a significant gap of large porphyry-skarn-type copper deposits in the region. This discovery holds great significance for prospecting and exploring efforts in the western Tianshan region. The spatial distribution of the Lamasu-Saibo copper deposit is controlled by fault zones and the intrusion of medium-acidic granitic rocks, and its formation is closely related to magmatic activity, making it a crucial prospecting indicator for mining areas. To identify the spatial distribution of ore-controlling fault zones and intermediate-acid granitic intrusive rocks, a combination of high-precision magnetic surveys and magnetotelluric (MT) soundings based on regional and geological characteristics were used. Both high-precision magnetic surveys and MT soundings indicated the presence of deep-seated, medium-acidic rocks within the mining area. At present, the Chagankol fault system and some east–west trending faults are believed to be the primary ore-controlling structures in this mining area. These structures serve as pathways for deep-seated magmas and ore-forming fluids, creating a favorable environment for mineralization. Analysis of the ore-forming model of this deposit with respect to its geological-geophysical characteristics served as the basis for a prospective model for porphyry-skarn-type copper deposits in the Lamasu-Saibo area. Based on this prospective model and existing drilling data, the spatial distribution of the main orebodies in the deep underground mining area was determined. In summary, this study identified three anomalous zones. Zones I and II, on the basis of available exploration results, located within 1000 m of the subsurface, exhibit promising prospects for mineral exploration, while Zone III also showed good exploration potential. These findings provide valuable guidance for future prospecting efforts in the Lamasu-Saibo copper deposit and serve as a reference for the exploration of porphyry-skarn-type copper deposits in the region.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"176 ","pages":"Article 106443"},"PeriodicalIF":3.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143139182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.oregeorev.2024.106438
Antonio Ciccolella , Fabrizio Tursi , Vincenzo Festa , Giovanni Ruggieri , Emanuela Schingaro , Gennaro Ventruti , Rosa Anna Fregola
Typically, Mississippi Valley Type (MVT) and Sediment-hosted Massive Sulphides (SHMS) Zn-Pb-deposits are hosted by sedimentary basins and are originated from fluids sourced from a crystalline basement. Mixing of fluids from crystalline basement and overlying sedimentary basins, through faults and fractures, is a major trigger for the formation of Zn-Pb deposits. In this context, Zn-Pb mineralization hosted in a crystalline basement and preserving a MVT-SHMS geochemical signature are rarely considered, although found. Here we present the results on a Zn-Pb(−Cu-Fe) mineralization associated to fault zones developed within Permian–Carboniferous intrusive bodies in the northern Sila Massif of Calabria (Italy), at Longobucco (LGB) and Fonte Argentila (FAR) localities. The ore-mineral assemblage consists of sphalerite, galena, ± chalcopyrite, and pyrite. We identified four distinct stages and three generations of sphalerite (Sp1, Sp2, Sp3), characterizing the paragenetic evolution of the mineralization. The Fe-content in sphalerite of LGB and FAR increases from Sp1 (medians of 3.34 and 2.46 wt%) to Sp2 (medians of 6.84 and 7.29 wt%), the latter containing the highest amounts of Cu (up to 1023 ppm), Ga (up to 338 ppm), Ge (up to 400 ppm), and Cd (up to 7589 ppm). Sp3 is characterized by the lowest Fe-content (median of 0.43 wt%) and formed after dissolution-precipitation of the earlier sphalerite generations. Based on the trace element signatures, the LGB-FAR sphalerite formed under low-temperature conditions (medians of 150–183 °C), as indicated by the GGIMFis geothermometer and the Ga/In, In/Ge and Zn/Cd ratios. The geochemical features and the low sulphur fugacity values (log10ƒS2 = 10−17.55–10−17.29 atm) suggest precipitation from an ore-forming fluid of MVT-SHMS/basinal derivation. This model is also supported by fluid inclusions data that record evidence from meteoric to high salinity basinal-type ore-forming fluids trapped within fluorite (Th = 72.2–114.6 °C; salinities from 0 to 21.2 wt% NaCl eq.). The later ore-forming fluids show meteoric and basinal-type with low to moderate salinity, as evidenced by fluid inclusions trapped within second quartz (Qz2) generation (Th = 111.6–163.8 °C; salinities of 0.5 to 6.1 wt% NaCl eq.). By comparing our results with those of similar Zn-Pb-deposits, we suggest that the fluids responsible for the peculiar vein-type LGB-FAR mineralization had several characteristics comparable to those related to MVT-SHMS deposits, although we cannot exclude at least an indirect magmatic contribution to the mineralizing fluids.
{"title":"MVT-SHMS signature in basement-hosted Zn-Pb-(Cu-Fe) mineralization in the Sila Massif (Calabria, Italy): Evidence from trace elements and fluid inclusions data","authors":"Antonio Ciccolella , Fabrizio Tursi , Vincenzo Festa , Giovanni Ruggieri , Emanuela Schingaro , Gennaro Ventruti , Rosa Anna Fregola","doi":"10.1016/j.oregeorev.2024.106438","DOIUrl":"10.1016/j.oregeorev.2024.106438","url":null,"abstract":"<div><div>Typically, Mississippi Valley Type (MVT) and Sediment-hosted Massive Sulphides (SHMS) Zn-Pb-deposits are hosted by sedimentary basins and are originated from fluids sourced from a crystalline basement. Mixing of fluids from crystalline basement and overlying sedimentary basins, through faults and fractures, is a major trigger for the formation of Zn-Pb deposits. In this context, Zn-Pb mineralization hosted in a crystalline basement and preserving a MVT-SHMS geochemical signature are rarely considered, although found. Here we present the results on a Zn-Pb(−Cu-Fe) mineralization associated to fault zones developed within Permian–Carboniferous intrusive bodies in the northern Sila Massif of Calabria (Italy), at Longobucco (LGB) and Fonte Argentila (FAR) localities. The ore-mineral assemblage consists of sphalerite, galena, ± chalcopyrite, and pyrite. We identified four distinct stages and three generations of sphalerite (Sp1, Sp2, Sp3), characterizing the paragenetic evolution of the mineralization. The Fe-content in sphalerite of LGB and FAR increases from Sp1 (medians of 3.34 and 2.46 wt%) to Sp2 (medians of 6.84 and 7.29 wt%), the latter containing the highest amounts of Cu (up to 1023 ppm), Ga (up to 338 ppm), Ge (up to 400 ppm), and Cd (up to 7589 ppm). Sp3 is characterized by the lowest Fe-content (median of 0.43 wt%) and formed after dissolution-precipitation of the earlier sphalerite generations. Based on the trace element signatures, the LGB-FAR sphalerite formed under low-temperature conditions (medians of 150–183 °C), as indicated by the GGIMFis geothermometer and the Ga/In, In/Ge and Zn/Cd ratios. The geochemical features and the low sulphur fugacity values (log<sub>10</sub>ƒS<sub>2</sub> = 10<sup>−17.</sup>55–10<sup>−17.</sup>29 atm) suggest precipitation from an ore-forming fluid of MVT-SHMS/basinal derivation. This model is also supported by fluid inclusions data that record evidence from meteoric to high salinity basinal-type ore-forming fluids trapped within fluorite (T<sub>h</sub> = 72.2–114.6 °C; salinities from 0 to 21.2 wt% NaCl eq.). The later ore-forming fluids show meteoric and basinal-type with low to moderate salinity, as evidenced by fluid inclusions trapped within second quartz (Qz2) generation (T<sub>h</sub> = 111.6–163.8 °C; salinities of 0.5 to 6.1 wt% NaCl eq.). By comparing our results with those of similar Zn-Pb-deposits, we suggest that the fluids responsible for the peculiar vein-type LGB-FAR mineralization had several characteristics comparable to those related to MVT-SHMS deposits, although we cannot exclude at least an indirect magmatic contribution to the mineralizing fluids.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"176 ","pages":"Article 106438"},"PeriodicalIF":3.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143139181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.oregeorev.2024.106429
Xu Wang , Yu Zhang , Xia Hu , Hongjie Shen , Lianjie Zhao , Xiyue Zheng , Shuling Song
The Mid-Late Jurassic is a significant period characterized by extensive magmatism and mineralization within the Qinhang metallogenic belt. However, the genesis and metallogenic potential of these Mid-Late Jurassic granitoids in the Dayaoshan district, the southwest part of the Qinhang metallogenic belt, remain inadequately investigated.
The Dayaoshan Mid-Late Jurassic granitoids primarily comprise the Fuqing granodiorite (161.5 ± 3.2 Ma), Dabang granodiorite (157.4 ± 2.4 Ma), Dabang granodiorite porphyry (155.9 ± 2.8 Ma), Shangdong granodiorite (153.7 ± 2.8 Ma), Fenghuang granodiorite (162.6 ± 1.1 Ma), and Yuanzhuding granite porphyry (154.3 ± 1.7 Ma). These rocks exhibit typical I-type affinity, marked by lower A/CNK values (0.9–1.1) and the presence of magnetite. Whole-rock Nb/Ta ratios (9.0–14.0), biotite major elements, apatite trace elements, Mg# value (35–63), and zircon εHf(t) (–19.7–4.2) and TDM2 (2440–834 Ma) indicate that the Dayaoshan Mid-Late Jurassic granitoids likely originated from remelting Precambrian metamorphic crustal material with some mantle material inputting. The higher Mg# value (52–63) and more positive εHf(t) value (–6.3–4.2) of the Yuanzhuding granite porphyry, genetically associated with porphyry Cu-Mo mineralization, suggest it contains more mantle-derived material compared to other granitoids. Regarding magma evolution, apatite and/or whole-rock trace elements show that the Fuqing granodiorite is dominated by amphibole fractionation, while the Dabang granodiorite, Dabang granodiorite porphyry, and Shangdong granodiorite are characterized by plagioclase fractionation. Based on the existing research on the Mid-Late Jurassic tectonic-magmatic activities in the Qinghang metallogenic belt, it is inferred that the Dayaoshan Mid-Late Jurassic granitoids are products of asthenospheric upwelling caused by the subduction of the Paleo-Pacific plate. The Dayaoshan Mid-Late Jurassic granitoids, excluding the Yuanzhuding granite porphyry, generally exhibit characteristics of low differentiation, low oxygen fugacity, and crust-mantle mixed source, thereby excluding the possibility of associated W-Sn and Cu mineralization. The mineralization age (Mid-Late Jurassic) along with S–Pb–H–O isotope compositions of lode gold deposits in the Dayaoshan region support their genetic linkage with the Mid-Late Jurassic magmatism, consistent with high water and gold content and low differentiation of the Dayaoshan Mid-Late Jurassic granitoids (except Yuanzhuding). This research highlights a good prospect for lode gold deposits around the Mid-Late Jurassic granitoids in Dayaoshan.
{"title":"Mid-Late Jurassic magmatism and its mineralization potential in the Dayaoshan district, southwest Qinhang metallogenic belt, South China","authors":"Xu Wang , Yu Zhang , Xia Hu , Hongjie Shen , Lianjie Zhao , Xiyue Zheng , Shuling Song","doi":"10.1016/j.oregeorev.2024.106429","DOIUrl":"10.1016/j.oregeorev.2024.106429","url":null,"abstract":"<div><div>The Mid-Late Jurassic is a significant period characterized by extensive magmatism and mineralization within the Qinhang metallogenic belt. However, the genesis and metallogenic potential of these Mid-Late Jurassic granitoids in the Dayaoshan district, the southwest part of the Qinhang metallogenic belt, remain inadequately investigated.</div><div>The Dayaoshan Mid-Late Jurassic granitoids primarily comprise the Fuqing granodiorite (161.5 ± 3.2 Ma), Dabang granodiorite (157.4 ± 2.4 Ma), Dabang granodiorite porphyry (155.9 ± 2.8 Ma), Shangdong granodiorite (153.7 ± 2.8 Ma), Fenghuang granodiorite (162.6 ± 1.1 Ma), and Yuanzhuding granite porphyry (154.3 ± 1.7 Ma). These rocks exhibit typical I-type affinity, marked by lower A/CNK values (0.9–1.1) and the presence of magnetite. Whole-rock Nb/Ta ratios (9.0–14.0), biotite major elements, apatite trace elements, Mg<sup>#</sup> value (35–63), and zircon ε<sub>Hf</sub>(t) (–19.7–4.2) and T<sub>DM2</sub> (2440–834 Ma) indicate that the Dayaoshan Mid-Late Jurassic granitoids likely originated from remelting Precambrian metamorphic crustal material with some mantle material inputting. The higher Mg<sup>#</sup> value (52–63) and more positive ε<sub>Hf</sub>(t) value (–6.3–4.2) of the Yuanzhuding granite porphyry, genetically associated with porphyry Cu-Mo mineralization, suggest it contains more mantle-derived material compared to other granitoids. Regarding magma evolution, apatite and/or whole-rock trace elements show that the Fuqing granodiorite is dominated by amphibole fractionation, while the Dabang granodiorite, Dabang granodiorite porphyry, and Shangdong granodiorite are characterized by plagioclase fractionation. Based on the existing research on the Mid-Late Jurassic tectonic-magmatic activities in the Qinghang metallogenic belt, it is inferred that the Dayaoshan Mid-Late Jurassic granitoids are products of asthenospheric upwelling caused by the subduction of the Paleo-Pacific plate. The Dayaoshan Mid-Late Jurassic granitoids, excluding the Yuanzhuding granite porphyry, generally exhibit characteristics of low differentiation, low oxygen fugacity, and crust-mantle mixed source, thereby excluding the possibility of associated W-Sn and Cu mineralization. The mineralization age (Mid-Late Jurassic) along with S–Pb–H–O isotope compositions of lode gold deposits in the Dayaoshan region support their genetic linkage with the Mid-Late Jurassic magmatism, consistent with high water and gold content and low differentiation of the Dayaoshan Mid-Late Jurassic granitoids (except Yuanzhuding). This research highlights a good prospect for lode gold deposits around the Mid-Late Jurassic granitoids in Dayaoshan.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"176 ","pages":"Article 106429"},"PeriodicalIF":3.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143139216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.oregeorev.2024.106413
Yun-He Zhou , Lin-Bo Shang , I-Ming Chou , Chen Chen , Zi-Qi Jiang , Xin-Song Wang , Jian-Guo Li
In geological processes, thermochemical sulphate reduction (TSR) is a significant way to transform oxidising sulphur into reducing sulphur, such as H2S, that can promote the formation of metal sulphide deposits. The occurrence of TSR is a complex process, where all kinds of sulphate, organic matter, and catalysis materials are involved, in which Al exists commonly in geological background. In order to figure out the function of Al in the TSR process, a series of experiments were conducted to investigate the TSR by using fused silica capillary capsules combined with Raman spectroscopy at temperatures ranging from 250°C to 350°C in this study. Ethanol (cracked into ethylene by heating) or acetic acid was used as reducing agents, and sodium sulphate or magnesium sulphate as oxidising agents, and the AlCl3 was introduced as a variable to investigate its effect on the initiation of TSR. Raman spectra were collected from the quenched and in-situ experiments. The results indicate that the addition of AlCl3 favours the initiation of TSR. In-situ Raman investigation reveals that HSO4- is the dominant sulphate species involved in TSR under our experimental conditions. This facilitating effect of AlCl3 on TSR has been attributed to the increased acidity in solution caused by the release of H+ through the formation of Al3+-bearing minerals such as natroalunite, where the released H+ combines with SO42- to form HSO4-. And SO2 was detected as an intermediate product during the reduction of HSO4- by in situ Raman spectroscopy. The experimental results imply that it is possible that the TSR can occur and accumulate enough reduced sulphur in a short period of time in an aluminium-rich geological environment at temperatures as low as 250°C.
{"title":"Effects of Al3+ on thermochemical sulphate reduction (TSR) at 250°C to 350°C under vapour-saturated pressures: A Raman spectroscopic investigation","authors":"Yun-He Zhou , Lin-Bo Shang , I-Ming Chou , Chen Chen , Zi-Qi Jiang , Xin-Song Wang , Jian-Guo Li","doi":"10.1016/j.oregeorev.2024.106413","DOIUrl":"10.1016/j.oregeorev.2024.106413","url":null,"abstract":"<div><div>In geological processes, thermochemical sulphate reduction (TSR) is a significant way to transform oxidising sulphur into reducing sulphur, such as H<sub>2</sub>S, that can promote the formation of metal sulphide deposits. The occurrence of TSR is a complex process, where all kinds of sulphate, organic matter, and catalysis materials are involved, in which Al exists commonly in geological background. In order to figure out the function of Al in the TSR process, a series of experiments were conducted to investigate the TSR by using fused silica capillary capsules combined with Raman spectroscopy at temperatures ranging from 250°C to 350°C in this study. Ethanol (cracked into ethylene by heating) or acetic acid was used as reducing agents, and sodium sulphate or magnesium sulphate as oxidising agents, and the AlCl<sub>3</sub> was introduced as a variable to investigate its effect on the initiation of TSR. Raman spectra were collected from the quenched and in-situ experiments. The results indicate that the addition of AlCl<sub>3</sub> favours the initiation of TSR. In-situ Raman investigation reveals that HSO<sub>4</sub><sup>-</sup> is the dominant sulphate species involved in TSR under our experimental conditions. This facilitating effect of AlCl<sub>3</sub> on TSR has been attributed to the increased acidity in solution caused by the release of H<sup>+</sup> through the formation of Al<sup>3+</sup>-bearing minerals such as natroalunite, where the released H<sup>+</sup> combines with SO<sub>4</sub><sup>2-</sup> to form HSO<sub>4</sub><sup>-</sup>. And SO<sub>2</sub> was detected as an intermediate product during the reduction of HSO<sub>4</sub><sup>-</sup> by in situ Raman spectroscopy. The experimental results imply that it is possible that the TSR can occur and accumulate enough reduced sulphur in a short period of time in an aluminium-rich geological environment at temperatures as low as 250°C.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"176 ","pages":"Article 106413"},"PeriodicalIF":3.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143139180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.oregeorev.2024.106406
Qingshuang Wang , Hu Peng , Chao Liu , Zhongyue Zhang , Yongheng Zhou , Xiaodan Guo , Nan Ju , QiuLin Fu , Yan Hao
The southern Songliao Basin harbors uranium-bearing rock series characterized by two distinct sedimentary environments: humid and arid, each displaying marked variations in the abundance of reducing agents and the spatial distribution of uranium mineralization. This comprehensive study meticulously delves into the petrology, mineralogy, and petrogeochemistry of the Lower Cretaceous Fuxin Formation (humid environment) and the Upper Cretaceous Quantou and Yaojia Formations (arid environment). Within these uranium-rich rock series, uranium minerals predominantly reside within coarse clastic rocks, particularly occupying interstitial spaces between clastic particles and their edges, with minor occurrences within mineral interiors or adsorbed on surfaces. Notably, the Fuxin Formation stands out for its stronger association of uranium minerals with carbonaceous detritus and pyrite. The unusually abundant internal reducing agents, like carbonaceous detritus and pyrite, within the Fuxin Formation’s uranium-bearing rocks, impede the development of interlayer oxidation zones, resulting in uranium mineralization concentrated near basin margins. Conversely, the Quantou and Yaojia Formations exhibit a relative paucity of internal reducing agents, while external sources like coal seams and hydrocarbon reservoirs accumulate centrally within the basin. This configuration promotes the extensive spread of interlayer oxidation zones and uranium mineralization deep into the basin’s interior. In essence, the abundance and spatial distribution of reducing agents determine the extent and pattern of interlayer oxidation zones and uranium mineralization. Both internal and external reducing agents intricately interact to orchestrate the uranium mineralization processes.
{"title":"Constraints of reducing media on uranium mineralization in the uranium-bearing rock systems of the southern Songliao Basin","authors":"Qingshuang Wang , Hu Peng , Chao Liu , Zhongyue Zhang , Yongheng Zhou , Xiaodan Guo , Nan Ju , QiuLin Fu , Yan Hao","doi":"10.1016/j.oregeorev.2024.106406","DOIUrl":"10.1016/j.oregeorev.2024.106406","url":null,"abstract":"<div><div>The southern Songliao Basin harbors uranium-bearing rock series characterized by two distinct sedimentary environments: humid and arid, each displaying marked variations in the abundance of reducing agents and the spatial distribution of uranium mineralization. This comprehensive study meticulously delves into the petrology, mineralogy, and petrogeochemistry of the Lower Cretaceous Fuxin Formation (humid environment) and the Upper Cretaceous Quantou and Yaojia Formations (arid environment). Within these uranium-rich rock series, uranium minerals predominantly reside within coarse clastic rocks, particularly occupying interstitial spaces between clastic particles and their edges, with minor occurrences within mineral interiors or adsorbed on surfaces. Notably, the Fuxin Formation stands out for its stronger association of uranium minerals with carbonaceous detritus and pyrite. The unusually abundant internal reducing agents, like carbonaceous detritus and pyrite, within the Fuxin Formation’s uranium-bearing rocks, impede the development of interlayer oxidation zones, resulting in uranium mineralization concentrated near basin margins. Conversely, the Quantou and Yaojia Formations exhibit a relative paucity of internal reducing agents, while external sources like coal seams and hydrocarbon reservoirs accumulate centrally within the basin. This configuration promotes the extensive spread of interlayer oxidation zones and uranium mineralization deep into the basin’s interior. In essence, the abundance and spatial distribution of reducing agents determine the extent and pattern of interlayer oxidation zones and uranium mineralization. Both internal and external reducing agents intricately interact to orchestrate the uranium mineralization processes.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"176 ","pages":"Article 106406"},"PeriodicalIF":3.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143139320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号