Acta Geochimica最新文献

{"title":"The discovery of Late Triassic hypabyssal mafic dykes in the Huozhou complex and their geological significance: Evidence from petrology, geochemistry, and geochronology","authors":"Haiyan Liu,&nbsp;Chong Peng","doi":"10.1007/s11631-024-00741-y","DOIUrl":"10.1007/s11631-024-00741-y","url":null,"abstract":"<div><p>The Huozhou complex in the Trans-North China Orogen exhibits two events of mafic magmatism (separated by ca. 700 Ma): Neoproterozoic (920 ± 15 Ma) Shimenyu diabase and Late Triassic (217 ± 2.5 Ma) Xingtangsi diabase. Investigations have focused on systematic petrology, zircon U-Pb dating, Lu-Hf isotopes, and lithogeochemistry. The research findings indicate that the Late Triassic Xingtangsi diabase of the Huozhou complex can be classified as a transitional type between intermediate and mafic rocks based on their SiO₂ content. This classification is supported by an average SiO₂ content of 53.94%, ranging from 53.33% to 54.28%. In the Zr/TiO₂ vs. Ce diagram, all samples lie within the range of basalt. The zircons from the Late Triassic Xingtangsi diabase have low ε_Hf(t) values ranging from –12.7 to –8.7, with an average of –11.1. Additionally, the single-stage model age T_DM1 is estimated to be between 1207 and 1701 Ma. These findings suggest that the magma responsible for the dyke originated from either partial melting or an enriched mantle source inside the Meso-Proterozoic lithospheric mantle. The elevated concentrations of Th (thorium) and LREEs (light rare earth elements), as well as the Th/Yb and Th/Nb ratios, suggest the potential incorporation of subducted sediments within the magma source region. The rock displays negative Nb, Ta, Zr, Hf, and Ti anomalies. These geochemical attributes align with the distinctive traits observed in volcanic rocks found within island arcs. The formation of the Late Triassic Xingtangsi diabase is likely associated with the geological context of an arc setting, which arises from the collision between the Yangtze plate and the North China Craton.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 6","pages":"1013 - 1036"},"PeriodicalIF":1.4,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mineralogical study and significance of the basalt-hosted Carlin-type Au deposits in southwestern Guizhou Province, China","authors":"Yuhong Yang,&nbsp;Shen Liu,&nbsp;Jianzhong Liu,&nbsp;Zepeng Wang,&nbsp;Bingqiang Zhang,&nbsp;Chengfu Yang","doi":"10.1007/s11631-024-00728-9","DOIUrl":"10.1007/s11631-024-00728-9","url":null,"abstract":"<div><p>The Jiadi and Damaidi gold deposits in southwest Guizhou Province are the largest basalt-hosted Carlin-type gold deposits recently discovered in China. This study uses the Tescan Integrated Mineral Analyzer, supported by detailed field investigations, regional geological data, and extensive sample collections, including mineralized ore, altered wall rock, and unaltered basalt samples, for ore-bearing and geochemical analyses. Comparative analysis between altered and unaltered basalt samples revealed a mineral assemblage of sericite, quartz, and pyrite. This mineral composition forms through the hydrothermal alteration of unaltered basalt, originally containing feldspar, pyroxene, and ilmenite. The wall rock primarily features sericite, quartz, and hematite. During the alteration process, major, trace, and rare earth elements notably migrate. In the Jiadi deposit, K₂O, Rb, Au, and REE significantly increase, while Na₂O, CaO, MgO, and MnO decrease. SiO₂, Al₂O₃, and Fe₂O₃ levels remain relatively stable. In the Damaidi deposit, K₂O, Rb, and Au enrich, contrasting with the depletion of Na₂O, CaO, MgO, and MnO, while SiO₂, Fe₂O₃, Al₂O₃, TiO₂, and REE show no significant changes. In the wall rock, TiO₂, Al₂O₃, K₂O, and REE increase, while Na₂O, CaO, MgO, and MnO decrease; SiO₂ and Fe₂O₃ content remains unchanged. The mineralization process likely originated from mid- to low-temperature, reductive magmatic hydrothermal fluids rich in CO₂, CH₄, N₂, H⁺, S²⁻, HS⁻, H₃AsO₃, and [Au(HS)₂]⁻. These fluids migrated to tectonically weak zones in the Lianhuashan area, where Emeishan basalts are present. They reacted with Fe-bearing minerals in the basalt, such as ferro-hornblende and ilmenite, forming pyrite, arsenic-bearing pyrite, and arsenopyrite, thus enriching Au in these minerals. Additionally, K⁺ and H⁺ in the fluid reacted with plagioclase in the basalt, forming sericite and quartz. As the fluid entered the wall rock from structural weak zones, its oxidation increased, leading to the complete or partial reaction of Fe-bearing minerals in the wall rock, resulting in the formation of hematite or magnetite. This mineralization process is similar to that observed in carbonate-hosted Carlin-type gold deposits in southwest Guizhou, with the primary distinction being the iron source. In carbonate deposits, iron originates from ferridolomite within the wall rock, while in basalt-hosted deposits, it derives from ferripyroxene and ilmenite.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 6","pages":"1241 - 1254"},"PeriodicalIF":1.4,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Precise and accurate Ga isotope ratio measurements of geological samples by multi-collector inductively coupled plasma mass spectrometry","authors":"Yuxu Zhang,&nbsp;Pan Qiao,&nbsp;Chuanwei Zhu,&nbsp;Haifeng Fan,&nbsp;Hanjie Wen","doi":"10.1007/s11631-024-00729-8","DOIUrl":"10.1007/s11631-024-00729-8","url":null,"abstract":"<div><p>Gallium isotope is a potential geochemical tool for understanding planetary processes, environmental pollution, and ore deposit formation. The reported Ga isotope compositions (δ⁷¹Ga_NIST994 values) of some international geological standards, such as BCR-2 and BHVO-2 basalts, exhibit inconsistencies between different laboratories. During mass spectrometry analysis, we found that δ⁷¹Ga_NIST994 values of geological standards with or without the correction of the interference of ¹³⁸Ba²⁺ (mass/charge ratio = 69) on ⁶⁹Ga show significant isotope offsets, and thus efficient separation of Ba and correcting the interference of ¹³⁸Ba²⁺ are both crucial to obtain accurate δ⁷¹Ga values. By comparing δ⁷¹Ga_NIST994 values (relative to NIST SRM 994 Ga) of the same geostandards from different laboratories, we suggest that the isotopic heterogeneity from NIST SRM 994 Ga is one of the key reasons for the inconsistencies in δ⁷¹Ga_NIST994 values of BCR-2 and BHVO-2. To facilitate inter-laboratory comparisons, we measured the Ga isotopic compositions of 11 geological reference materials (including Pb-Zn ore, bauxite, igneous rocks, and loess) and two Ga solution standards (NIST SRM 3119a and Alfa Aesar). The δ⁷¹Ga_NIST994 and δ⁷¹Ga_IPGP values of these reference materials vary from 1.12 ‰ to 2.63 ‰ and − 0.13 ‰ to 1.38 ‰, respectively, and can be used to evaluate the precision and accuracy of Ga isotope data from different laboratories.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 6","pages":"1054 - 1064"},"PeriodicalIF":1.4,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geology and S-Pb isotope geochemistry of the Hatu gold deposit in West Junggar, NW China: Insights into ore genesis and metal source","authors":"Shen Han,&nbsp;Zhenju Zhou,&nbsp;Xiaohua Deng,&nbsp;Yanshuang Wu,&nbsp;Xi Chen,&nbsp;Abulimiti Aibai,&nbsp;Yong Wang,&nbsp;Xiaoyu Jia,&nbsp;Yanjing Chen","doi":"10.1007/s11631-024-00727-w","DOIUrl":"10.1007/s11631-024-00727-w","url":null,"abstract":"<div><p>The Hatu gold deposit is the largest historical gold producer of the West Junggar, western China, with an Au reserve of about 62 t. The orebodies were controlled by NE-, EW-, and NW-trending subsidiary faults associated with the Anqi fault. This deposit exhibits characteristics typical of a fault-controlled lode system, and the orebodies consist of auriferous quartz veins and altered wall rocks within Early Carboniferous volcano-sedimentary rocks. Three stages of mineralization have been identified in the Hatu gold deposit: the early pyrite-albite-quartz stage, the middle polymetallic sulfides-ankerite-quartz stage, and late quartz-calcite stage. The sulfur isotopic values of pyrite and arsenopyrite vary in a narrow range from − 0.8‰ to 1.3‰ and an average of 0.4‰, the near-zero δ³⁴S values implicate the thorough homogenization of the sulfur isotopes during the metamorphic dehydration of the Early Carboniferous volcano-sedimentary rocks. Lead isotopic results of pyrite and arsenopyrite (²⁰⁶Pb/²⁰⁴Pb = 17.889–18.447, ²⁰⁷Pb/²⁰⁴Pb = 15.492–15.571, ²⁰⁸Pb/²⁰⁴Pb = 37.802–38.113) are clustered between orogenic and mantle/upper crust lines, indicating that the lead was mainly sourced from the hostrocks within the Early Carboniferous Tailegula Formation. The characteristics of S and Pb isotopes suggest that the ore-forming metals of the Hatu orogenic gold deposit are of metamorphogenic origin, associated with the continental collision between the Yili-Kazakhstan and Siberian plates during the Late Carboniferous.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 6","pages":"1205 - 1222"},"PeriodicalIF":1.4,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ore-forming mechanism of Huxu Au-dominated polymetallic deposit in the Dongxiang Basin, South China: Constraints from in-situ trace elements and S–Pb isotopes of pyrite","authors":"Hongze Gao,&nbsp;Jiajie Chen,&nbsp;Chengbiao Leng,&nbsp;Yuhui Hu,&nbsp;Huidan Xie,&nbsp;Zenghua Li","doi":"10.1007/s11631-024-00726-x","DOIUrl":"10.1007/s11631-024-00726-x","url":null,"abstract":"<div><p>The Huxu Au-dominated polymetallic deposit is a hydrothermal deposit located in the Dongxiang volcanic basin in the middle section of the Gan-Hang tectonic belt in South China. The orebodies primarily occur within the Jurassic-Cretaceous quartz diorite porphyry, while the genesis of this deposit is unclear. This study focused on geological and mineralogical characteristics, <i>in-situ</i> trace elements and S-Pb isotopes of three generations of pyrite of the Huxu deposit to clarify the distribution of trace elements in pyrite, ore-forming fluid and material sources, and genetic types of the deposit. The mineralization stage of the deposit can be divided into quartz-pyrite stage (S1), quartz-pyrite-hematite stage (S2), quartz-polymetallic sulfide stage (S3) and quartz-hematite stage (S4), with the corresponding pyrite being divided into three generations (Py1–Py3). <i>in-situ</i> trace element data of pyrite show that Au in pyrite mainly exists in the form of solid solution (Au⁺), and the content is relatively low at all stages (0.18 ppm for Py1, 0.32 ppm for Py2, 0.68 ppm for Py3), while Pb and Zn mainly exist as sulfide inclusions in the pyrite. S-Pb isotopes show that the sulfur and ore-forming material of this deposit are mainly sourced from magma. The mineral association, mineral textures and trace elements in different stages of pyrite indicate that fluid boiling and fluid mixing are the key factors of native gold precipitation in S2 and S4, respectively, while water-rock interaction controlled the precipitation of Pb-Zn sulfides. These integrating with geological characteristics suggests that the deposit should be an intermediate sulfidation epithermal deposit.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 6","pages":"1223 - 1240"},"PeriodicalIF":1.4,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mineralogical and geochemical characterization of the Wadi Natash volcanic field (WNVF), Egypt: Alkaline magmatism in a Late Cretaceous continental rift system","authors":"Adel A. Surour,&nbsp;Ahmed A. Madani,&nbsp;Mohamed A. El-Sharkawi","doi":"10.1007/s11631-024-00702-5","DOIUrl":"10.1007/s11631-024-00702-5","url":null,"abstract":"<div><p>The Wadi Natash volcanic field (WNVF) in the south of the Eastern Desert of Egypt is a typical example of well-preserved intraplate alkaline magmatism during the Late Cretaceous, i.e., prior to the Oligo-Miocene Red Sea rift. We compiled stratigraphic sections at two sectors; namely East Gabal Nuqra and West Khashm Natash (WKN) where the volcanic flows are intercalated with the Turonian Abu Agag sandstone with occasional paleosols when volcanic activity is intermittent. Peridotite mantle xenoliths are encountered in the first sector whereas flows in the second sector are interrupted by trachyte plugs and ring dykes. On a geochemical basis, the mafic melt originating from the lithospheric mantle beneath the WNVF practiced ~ 5% partial melting of phlogopite-bearing garnet peridotite. Basalts dominate in the two sectors and highly evolved (silicic) rocks are confined to the WKN sector. Rejuvenation of ancient Precambrian fractures following the NW–SE and ENE-WSW trends facilitated the ascend of Late Cretaceous mantle-derived alkaline magma. Structurally, the WNVF developed at the eastern shoulder of the so-called “Kom Ombo-Nuqra-Kharit rift system” that represents a well-defined NW-trending intracontinental rift basin in the southern Eastern Desert. In such a structural setup, the Natash volcanic are confined to half-grabens at the East Gabal Nuqra sector whereas the West Khashm Natash sector is subjected to extensional stresses that propagated eastwards. The WNVF is a typical example of fluvial clastics (Turonian) intercalation with rift-related alkaline volcanic rocks in northeast Africa.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 6","pages":"1169 - 1191"},"PeriodicalIF":1.4,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genesis and geological significance of carbonate in Changdu Basin, Xizang, China: Constraints from geochemistry and C–O isotopes","authors":"Wenhua Han,&nbsp;Yongshou Li,&nbsp;Haizhou Ma,&nbsp;Huaide Cheng,&nbsp;Binkai Li,&nbsp;Qinyu Hai,&nbsp;Xuahai Ma","doi":"10.1007/s11631-024-00704-3","DOIUrl":"10.1007/s11631-024-00704-3","url":null,"abstract":"<div><p>Research on the origin of carbonates in Changdu Basin holds significant importance for understanding the regional potash formation model. Based on a comprehensive review of previous studies, field geological surveys, and laboratory investigations, this study analyzes the origin and properties of carbonates within the context of regional potash formation. Petrographic studies show that magnesite deposits, with the characteristics of sedimentary origin. The results of elemental geochemical analysis show that the carbonates in this area were formed in the sedimentary environment via evaporation followed by concentration, and the formation of magnesite was possibly caused by the substitution of calcium in the dolomite with magnesium-rich brine. The δ¹³C values of carbonats in the study area are between 5.9‰ and 9.1‰. The δ¹⁸O values of magnesite samples range from − 7.3‰ to − 1.3‰, and the δ¹⁸O values of dolomites range from − 10.3‰ to − 8.4‰. All the calculated Z values of oxygen isotopes of carbonates greater than 120. A comprehensive analysis of carbon and oxygen isotopes indicates that the magnesite was formed in a highly concentrated Marine sedimentary environment and does not show any relation with the metasomatism of hydrothermal fluids. The results on the correlation of magnesite with seawater and its sedimentary origin provide key information for explaining the migration direction of brine between the Changdu and Lanping–Simao Basins. The residual metamorphic seawater in the Changdu Basin migrated to the Lanping–Simao Basin, where potash underwent deposition. Whereas, magnesite and dolomite in the early stage of potash formation were left in the Changdu Basin.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 6","pages":"1192 - 1204"},"PeriodicalIF":1.4,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Catagenetic type of manganese ores: REE and isotope (δ13C, δ18O) geochemical features (on the example of the Usa deposit, Russia)","authors":"Vladimir N. Kuleshov,&nbsp;Andrey Yu. Bychkov,&nbsp;Irina Yu. Nikolaeva,&nbsp;Maria E. Tarnopolskaia","doi":"10.1007/s11631-024-00701-6","DOIUrl":"10.1007/s11631-024-00701-6","url":null,"abstract":"<div><p>Chemical (REE and major elements) and isotope (δ¹³C, δ¹⁸O) composition of carbonate manganese ores and manganese-bearing carbonates of the Usa deposit (Siberia, Russia) were studied. Received data on the composition of REE exhibit both the distinct negative (Ce/Ce*_PAAS &lt; 1) and positive (Ce/Ce*_PAAS˃1) cerium anomalies and the positive Eu-anomaly (Eu/Eu*_PAAS˃1). Negative Eu-anomalies are not observed. The contents of Mn, Fe, REE, and Ce-anomalies show a positive correlation with each other. Ce-anomalies and the amount of manganese and REE in relation to the carbon isotope composition (δ¹³C) show a negative relationship and indicate that oxidized carbon of organic matter played an important role in the concentration of manganese and REE in manganese ores. The chemical and isotope composition of examined rocks indicates on secondary formation of Mn-ores. Two major phases and sources are distinguished in the ore-forming process characterized by different chemical (REE and ore elements) and isotope composition: (i) high-grade manganese ores (with high contents of REE and light carbon isotope composition) and (ii) low-grade manganese ores (with low contents of REE and heavy carbon isotope composition).</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 6","pages":"1133 - 1152"},"PeriodicalIF":1.4,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141107604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Can soil remediation agents synergistically mitigate rice Cd content and CH4 emission from karst paddies?","authors":"Wangbiao Lu,&nbsp;Guangneng Zeng,&nbsp;Weijun Luo,&nbsp;Jiangju Song,&nbsp;Maofei Ni,&nbsp;Shuangqin Guo,&nbsp;Qi Zhang,&nbsp;Chengling Huang,&nbsp;Cheng Yang,&nbsp;Haijun Du,&nbsp;Shijie Wang","doi":"10.1007/s11631-024-00696-0","DOIUrl":"10.1007/s11631-024-00696-0","url":null,"abstract":"<div><p>Rice (<i>Oryza sativa</i> L.) paddies are increasingly threatened by cadmium (Cd) pollution, and potentially serve as CH₄ emitters to the atmosphere. Remediation agents widely mitigate Cd pollution in paddy soil, however, we know little about their regulations on CH₄ emission. Here, via adding biochar (B), sulfhydryl-modified palygorskite (SMP), and selenium foliar fertilizer (SFF), we conducted a pot experiment to investigate soil and rice Cd contents together with <i>in</i>-<i>situ</i> CH₄ fluxes. Compared to CK, the addition of SMP, SFF, and B-SMP reduced Cd in brown rice by 25% to 50%, 25%, and 50% to 75%, respectively. Agents 7% B, 7% B-0.01% SMP, and SFF reduced CH₄ emissions by 8.46%, 5.30%, and 4.11%, respectively. CH₄ emission increased gradually along the growing season, with the cumulative CH₄ fluxes ranging between 338.82 and 619.13 kg hm⁻². Our results highlight that mixed 7% B-0.01% SMP and SFF showed collaborative effects on Cd remediation and CH₄ emission. This study reveals the feasibility of reducing Cd pollution and CH₄ emission in karst rice paddies, which hopes to supplement the knowledge of collaborative controls on soil remediation and carbon emission.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 6","pages":"1123 - 1132"},"PeriodicalIF":1.4,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141106762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluid inclusion and H-O-S-Pb isotope systematics of the Chayong Cu-polymetallic deposit, Sanjiang Metallogenic Belt, Qinghai Province, China","authors":"Jian Wang,&nbsp;Hao Wang,&nbsp;Fengyue Sun,&nbsp;Fei Wang,&nbsp;Xiangwen Li,&nbsp;Hongju Yue","doi":"10.1007/s11631-024-00700-7","DOIUrl":"10.1007/s11631-024-00700-7","url":null,"abstract":"<div><p>The Chayong Cu-polymetallic deposit is a recently discovered Cu-polymetallic deposit hosted in the Sanjiang Metallogenic Belt within the Tibetan Plateau of China to the northeast of the North Qiangtang terrane. The ore body occurs in siltstone and is controlled by a northwest-trending fault structure. According to the associations, assemblages, and cutting relationships between ore veins, the hydrothermal mineralization period can be divided into three mineralization stages: (1) a molybdenite mineralization stage, (2) a Cu-polymetallic sulfide stage, and (3) a quartz-carbonate stage. Two types of fluid inclusions (FIs), namely, liquid and vapor-rich inclusions, are present in quartz associated with sulfide minerals. Early-stage FIs are both liquid and vapor-rich, homogenized at temperatures ranging from 364.1 to 384.2 °C, and have salinities ranging from 0.70% to 9.60% NaCl equivalent (eqv). The middle-stage FIs are also both liquid- and vapor-rich, homogenized at temperatures ranging from 272.4 to 355.6 °C, and have salinities ranging from 0.53%–17.10% NaCl eqv. The late-stage FIs are liquid, homogenized at temperatures ranging from 209.4 to 255.3 °C, and have salinities ranging from 0.35%–6.87% NaCl eqv. The samples from the deposit have δ³⁴S values of − 21.8‰ to − 19.2‰ and − 5.5‰ to − 6.0‰, suggesting that sulfur was derived from the host sediments and magmatic fluids, respectively. The metallic minerals within the deposit have ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, and ²⁰⁸Pb/²⁰⁴Pb values of 18.439–18.458, 15.656–15.679, and 38.772–38.863, respectively, suggesting that the metals were derived from the upper crust and orogenic belts. The samples from the deposit have δ¹⁸O_W values of 2.99‰–7.99‰ and δD_W values ranging from − 84.4‰ to − 73.9‰, indicating that the ore-forming fluids were magmatic and mixed with minor amounts of meteoric water. The ore-forming fluid of the Chayong copper polymetallic deposit was a high-temperature, medium- to low-salinity H₂O–NaCl–CH₄–N₂ ± CO₂ fluid system. The early high-temperature magmatic fluid, due to boiling, decreased in temperature, and via the mixing of meteoric water, gradually evolved towards the later-stage medium- to low-temperature and low-salinity fluid, causing molybdenite mineralization and forming copper polymetallic sulfide veins and quartz carbonate veins.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 6","pages":"1153 - 1168"},"PeriodicalIF":1.4,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141000864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}