Ore Geology Reviews最新文献

{"title":"K, Sr isotopes, and trace element to constrain potash origin in the Simao Basin, southwestern China, and insight into K isotope geochemical behavior in evaporite","authors":"Zhong-Ying Miao ,&nbsp;Mian-Ping Zheng ,&nbsp;Peng-Cheng Lou ,&nbsp;Zhi-Guang Xia ,&nbsp;Wei-Qiang Li ,&nbsp;Lin-Feng Shi ,&nbsp;Gao Song ,&nbsp;Xue-Fei Zhang ,&nbsp;Yuan-Ying Liu","doi":"10.1016/j.oregeorev.2024.106322","DOIUrl":"10.1016/j.oregeorev.2024.106322","url":null,"abstract":"<div><div>With the advancement of emerging potassium isotope testing techniques, the characteristics of <em>δ</em>⁴¹K in evaporite have garnered increasing attention. Its application in constraining the genesis of potash deposits and tracing the process of potash mineralization holds significant prospects. A comprehensive analysis of the geochemical characteristics of K, Sr isotopes, and trace elements provides an opportunity to address the ongoing debate regarding the mineralization mechanism of potash in the Simao Basin. In this study, we collected 64 potash samples from the Simao and Khorat basins. The analytical results revealed that the major ions in the samples consist of Na⁺, K⁺, Mg²⁺, Ca²⁺, Cl⁻, and SO₄^2-, while the trace elements Br, Sr, Rb, B, Li, V, Cr, Mn, Ba, As, and Zn are relatively enriched. The <em>δ</em>⁴¹K values range from −0.12 ‰ to 0.20 ‰ with an average of 0.01 ‰. The ⁸⁷Sr/⁸⁶Sr ratios range from 0.707553 to 0.708565 with an average of 0.708020, which is lower than that of the river water in the drainage basin. Additionally, the Br content ranges from 316.3 × 10⁻⁶ to 1709.1 × 10⁻⁶, with an average of 633.8 × 10⁻⁶. These data indicate that the Early Cretaceous Albian-Middle Jurassic Bajocian seawater serves as an important source of potassium for potash deposition in the Simao Basin. The characteristics of the ratios of the Br/Cl (mmol/mol), K/Cl (mmol/mol), Rb/Sr (mol/mol), along with the contents of the Br and Rb, indicate that the most of potash in the Simao Basin is primary origin. Moreover, we have also provided new insight into the geochemical behaviors of K isotopes during the evolution of the evaporites. The precipitation of potash may be accompanied by K isotope fractionation, as evidenced by the lighter K isotope composition of carnallite compared to that of sylvinite. K isotope fractionation occurs between the secondary sylvite and its parent source, and newly precipitated solids are characterized by relatively light K isotope. Episodic freshwater inflow into the evaporative basin stimulates microbial activity, leading to fluctuations in K isotopes in the precipitated potash during the same evaporation stage. Therefore, this work not only provided direct evidence from the K isotopes for determining the origin of the potash in the Simao Basin but also further perceived the geochemical behaviors of K isotopes during the evolution of evaporite.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"174 ","pages":"Article 106322"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651307","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}

{"title":"Geochronological and geochemical constraints on the multistage magmatic processes of the Lianhuashan batholith, South China: Implications for the petrogenesis and polymetallic mineralization","authors":"Jinhua Qin ,&nbsp;Denghong Wang ,&nbsp;Fan Huang ,&nbsp;Shihua Zhong","doi":"10.1016/j.oregeorev.2024.106327","DOIUrl":"10.1016/j.oregeorev.2024.106327","url":null,"abstract":"<div><div>The Lianhuashan batholith, which is a composite pluton located in the middle part of a world-class giant tungsten (W) polymetallic belt of South China, hosts a huge reserve of more than 50,000 t of W. Despite this great economic significance, the petrogenesis of each phase of the Lianhuashan batholith, as well as its temporal and genetic relationships to the W polymetallic mineralization, is still unclear. To address these questions, we conducted a comprehensive study for the Lianhuashan batholith, including LA-ICP-MS zircon U-Pb dating, whole-rock geochemical and in-situ mineral trace element analyses. Different from previous studies, four main granitic phases (G1–G4) were identified. The biotite granite (G1) formed from 168.6 to 165.3 Ma, has the lowest Si content and high Al and Fe contents, and is significantly depleted in Ba, Sr, Ti, P, and Nb whereas enriched in U, Hf, Zr, and Y contents. In contrast, the two-mica granite (G2) and fine-grained muscovite granite (G3), which formed from 162.8 to 160.5 Ma, exhibit similar characteristics including enrichment in La, Y, Hf, Th, U, and depletion in Ba, Sr, and P. The porphyritic granite (G4) is the latest magmatic phase and formed at 158.3 Ma. It is characterized by high K, Si, Th, U, Zr, Hf contents but low Al_, Fe, Sr, P, and Ti contents. These features support that four main phases of the Lianhuashan batholith belong to S-type granites that experienced significant fractional crystallization, and display reduced and low temperature features. Combined with previously published studies, we suggest that the Lianhuashan batholith formed in an intraplate extensional setting triggered by the high-angle rollback subduction of the paleo-Pacific plate. The three early phases (i.e., G1–G3) are in turn more oxidized and are responsible for the transition from Sn- to W-dominated mineralization. In contrast, the G4 granite, characterized by lower oxygen fugacity, is resposible for Pb-Zn-Ag-U polymetallic mineralization.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"174 ","pages":"Article 106327"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651220","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}

{"title":"Unraveling the metallogenic mechanisms of uranium-rich ore bodies: Insights from Xinqiaoxi’s pitchblende geochronology and pyrite geochemistry","authors":"Bin Liu ,&nbsp;Liang Qiu ,&nbsp;Jing Zou ,&nbsp;Jiaming Qi ,&nbsp;Haidong Li ,&nbsp;Yongqin Ye ,&nbsp;Jun-Ting Qiu ,&nbsp;Hongxu Mu","doi":"10.1016/j.oregeorev.2024.106305","DOIUrl":"10.1016/j.oregeorev.2024.106305","url":null,"abstract":"<div><div>Granite-related uranium deposits are essential for the global uranium supply, with the uranium-rich ore bodies within these deposits being crucial to their value. However, the sources of uranium, fluid characteristics, and metallogenic mechanisms within these uranium-rich ore bodies remain unclear. In this study, we analyzed pitchblende and pyrite from the Xinqiaoxi uranium deposit to determine uranium age and clarify the mineralization of uranium-rich ore bodies. The pitchblende samples provided a U-Pb age of 58.5 ± 3 Ma (MSWD = 3.4), closely aligns with the mineralization ages in other uranium deposits within the Xiazhuang uranium ore-field. This consistency suggests a significant uranium mineralization event in South China during this period. The vein-like and concentric structure of the pitchblende, coupled with its enrichment in U, Sr, As, W, and Mo but depletion in Th, Pb, and REEs, indicates a strong association with hydrothermal activity. Moreover, its REE pattern closely resembles that of the host rock (Xiazhuang and Maofeng granites), suggesting the latter as a crucial uranium source. Pyrite and pitchblende are coeval, yet pyrite was formed slightly earlier than pitchblende. Pyrite exhibits depletion in Co and Ni but enrichment in As, along with high Co/Ni ratios ranging from 1.68 to 12.2, indicative of a medium- to low temperature hydrothermal genesis. Furthermore, the positive cerium (Ce) anomaly observed in pyrite may indicate elevated oxygen fugacity in the fluids during precipitation. The δ³⁴S values of pyrite (−10.42 ‰ to −15.26 ‰, averaging −13.44 ‰) are consistent with those of the host rock (Xiazhuang and Maofeng granites), indicating a primary sulfur source from the host rock. Additionally, pyrite may serve as a reductant, facilitating the formation of uranium ore. Our proposed genetic model suggests that CO₂-rich oxidizing fluids facilitate uranium leaching from host rocks, resulting in the formation of a uranium-enriched fluid that migrates along faults, where U⁶⁺ undergoes reduction to U⁴⁺ within secondary fracture zones, facilitated by reductants such as pyrite.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"174 ","pages":"Article 106305"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572164","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}

{"title":"In situ U–Pb dating of dolomite: Reliable ages for sandstone-hosted uranium deposits in the southern Songliao Basin, NE China","authors":"Dongguang Yang ,&nbsp;Fengjun Nie ,&nbsp;Fei Xia ,&nbsp;Liangliang Zhang ,&nbsp;Yanwen Tang ,&nbsp;Zhaobin Yan ,&nbsp;Zhenfeng Yang ,&nbsp;Fumei Wang","doi":"10.1016/j.oregeorev.2024.106331","DOIUrl":"10.1016/j.oregeorev.2024.106331","url":null,"abstract":"<div><div>Previously, the ages of U mineralization in sandstone-hosted uranium deposits have not been adequately constrained due to the absence of suitable minerals for precise radiometric dating. To ascertain the mineralogenetic epoch and origin of the ore-forming fluids in the sandstone-hosted uranium deposits within the southern Songliao Basin of northeastern China, we conducted U–Pb dating, major and trace element analyses, and Sr isotope analyses on carbonate minerals taken from the sandstone. In this study, we present a novel U–Pb age of 92.5 ± 6.9 Ma (MSWD = 0.56) for calcite nodules, which is interpreted as the depositional age of the target formation hosting the ore. The age of the main mineralization stage is constrained by two types of high uranium carbonate minerals: the dolomite coexists with siderite and recrystallized framboidal pyrite, whereascoarse-grained ankerite occurs with dawsonite enveloping dolomite. The dolomite vein yields an age of ∼60 Ma (62.8 ± 0.5 Ma, MSWD = 2.7; 60.0 ± 0.4 Ma, MSWD = 6.4), the coarse-grained ankerite may be contemporaneous with the widely distributed diabase with an age of ∼40 Ma, which is interpreted two U mineralization ages. The ∼92 Ma calcite nodules are characterized by low U and U/Th ratios and relatively flat REE distribution patterns, and the high ⁸⁷Sr/⁸⁶Sr ratios (0.7109–0.7327) and the dispersed trace element composition can be attributed to fluid–rock interactions. In contrast, dolomite veins with an age of approximately 60 Ma exhibit elevated MnO and Y/Ho ratios, as well as patterns enriched in heavy rare earth elements (HREEs); the ⁸⁷Sr/⁸⁶Sr ratios range from 0.7066 to 0.7092, indicating their association with hydrocarbon seep-related carbonates of microbial origin. The coarse-grained ankerite, which has high REE + Y values and hump-shaped, MREE-enriched patterns with low Y/Ho ratios and negligible to positive Eu anomalies, combined with the spatial relationship between the ankerite-bearing sandstone sample and diabase, indicates that the ankerite is the product of hydrothermal processes. This ∼60 Ma dolomite presents initial evidence indicating that the Hulihai deposit is contemporaneous with a significant regional tectonic inversion event and preceded or coincided with hydrocarbon fluid activity in the southern Songliao Basin. Based on the spatial and temporal correlations, it is plausible that both the Palaeocene (∼60 Ma) tectonic reversal event and the Eocene hydrothermal event (∼40 Ma) were causally linked to sandstone-hosted uranium deposits in the southern Songliao Basin. The present study demonstrates the robustness of in situ carbonate mineral U–Pb dating as a valuable tool for geochronological investigations pertaining to sandstone-hosted uranium deposits.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"174 ","pages":"Article 106331"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586461","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}

{"title":"Geology and mineralization of the Yangla polymetallic orefield in northwestern Yunnan, SW China: Age, petrogenesis and rare-metal metallogenic implications of aplite dykes","authors":"Xinfu Wang ,&nbsp;Bo Li ,&nbsp;Shucheng Tan ,&nbsp;Changfen He ,&nbsp;Xiaoqing Liu ,&nbsp;Fengze Liu","doi":"10.1016/j.oregeorev.2024.106315","DOIUrl":"10.1016/j.oregeorev.2024.106315","url":null,"abstract":"<div><div>Aplite dykes commonly represent more evolved magma and are closely associated with rare metal mineralization. However, the multiphase magmatism and rare metal mineralization of aplite dykes in the Yangla orefield have not been well-constrained. Here, we present new data on the Linong aplite dykes and the associated Jiangbian granodiorite in the Yangla orefield, including data of zircon U-Pb age and Hf isotopes, and lithogeochemistry and Pb-Sr-Nd isotopes, in order to elucidate their emplacement age, petrogenesis, and rare metal mineralization potential. The three aplite dykes studied were emplaced at 214.3 ± 5.1 Ma, 209.2 ± 5.2 Ma, and 205.5 ± 3.4 Ma. These Late Triassic aplite dykes have high SiO₂ (75.81–76.94 wt%) and K₂O (avg. 5.60 wt%) and are peralkaline–metaluminous (A/CNK = 0.86–0.93). They have high whole-rock (⁸⁷Sr/⁸⁶Sr)_i (0.6947–0.7094), ε_Nd(t) (−6.26 to − 5.77), (²⁰⁶Pb/²⁰⁴Pb)_t = 18.365–18.804, (²⁰⁷Pb/²⁰⁴Pb)_t = 15.688–15.715, (²⁰⁸Pb/²⁰⁴Pb)_t = 38.436–38.681, and zircon ε_Hf(t) =  − 8.10 to + 1.62. The Triassic (208–228 Ma) Jiangbian granodiorite is high-K calc-alkaline, metaluminous/weakly peraluminous (A/CNK = 0.52–1.19) with high Al₂O₃ (12.49–16.74 wt%). They have high (⁸⁷Sr/⁸⁶Sr)_i (0.7075–0.7102), whole-rock ε_Nd(t) (−6.12 to − 5.88), (²⁰⁶Pb/²⁰⁴Pb)_t = 18.155–18.384, (²⁰⁷Pb/²⁰⁴Pb)_t = 15.665–15.698, (²⁰⁸Pb/²⁰⁴Pb)_t = 38.579–38.719, and zircon ε_Hf(t) =  − 4.20 to + 2.40. These geochemical features imply that both the aplite dykes and granodiorite have their primary magma derived from partial melting of the Proterozoic basement, with minor mantle input. The aplite samples have an average estimated crystallization temperature of 712 ℃, and relatively low magmatic oxygen fugacity ([log(fo₂)] = − 21.98 to – 5.48, avg. = –17.05), which are slightly higher than that of most Triassic granitoids in the Yangla orefield. The result shows that the crystallization temperature and oxygen fugacity gradually increase, while the ¹⁷⁶Hf/¹⁷⁷Hf and ε_Hf(t) gradually decrease. Our new and published geochemical data from the Yangla granitoids reveal that the aplite dykes and granodiorite were formed in a post-collisional setting. Whole-rock Nb/Ta, Zr/Hf, Rb/Sr, Ba/Rb, and zircon REE features of the aplite dykes highly mimic those of typical Sn-W related granites, suggesting certain Sn-W rare metals mineralization potential in the Yangla orefield.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"174 ","pages":"Article 106315"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586388","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}

{"title":"Trace element of epidote from the Tonglushan Cu-Fe-Au deposit, eastern China: Implications for exploration indicator for skarn mineralization","authors":"Qiaoqiao Zhu ,&nbsp;Guiqing Xie ,&nbsp;Lifan Lu ,&nbsp;Fang Yan ,&nbsp;Heng'an Cai","doi":"10.1016/j.oregeorev.2024.106298","DOIUrl":"10.1016/j.oregeorev.2024.106298","url":null,"abstract":"<div><div>Epidote is a common alteration phase in magmatic-hydrothermal deposits. It has been widely used as an indicator for vectoring mineralization centers and fertility assessments for porphyry ore deposits. However, whether epidote from skarn deposit without significant porphyry-style mineralization can also serve as an exploration indicator remains unclear. Major and trace elements of epidote from the quartz monzodiorite (porphyry) (QMD), endoskarn, Cu-Fe ore, and exoskarn/marble at Tonglushan were analyzed by electron microprobe analysis (EMPA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to constrain their variations across the deposit. The EMPA results suggest that the major compositions (e.g., Al, Fe, and Mn) of epidote are more likely to be affected by precursor minerals such as plagioclase, garnet, diopside, and features of fluid composition (e.g., <em>f</em>O₂, temperature, and Fe³⁺ abundance). Epidote trace elements, however, may controlled by coprecipitating minerals such as sulfides and magnetite, which may strongly enrich in certain elements (e.g., As, Sb, Co, Ti, and V) relative to the epidote, as well as precursor allanite which has significantly elevated trace elements (such as As and V) than the successor epidote replacement. The contents of Na, Mg, Mn, Co, and Sn in epidote show a general increase from QMD, through endoskarn, to Cu-Fe ore and then decreasing to exoskarn/marble whereas that of Sc, V, Y, Zr, Sb, and total REE show an opposite trend. The general patterns of these trace elements in skarn epidote may potentially indicate the direction of orebodies. The strong-moderate linear correlation (R² = 0.76 to 0.93) of As and Sb contents in epidote with the tonnage of Cu or distance from the magmatic-hydrothermal center demonstrates their potential as a quantitative evaluation tool. In general, the trace element contents of skarn epidote are expected to provide critical information for skarn deposit exploration.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"174 ","pages":"Article 106298"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651229","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}

{"title":"Hydrothermal niobium (Nb) mineralization and mobilization in the world-class Madeira Sn-Nb-Ta granitic deposit (Amazonas, Brazil)","authors":"Quentin Bollaert ,&nbsp;Mathieu Chassé ,&nbsp;Artur Bastos Neto ,&nbsp;Adriana Horbe ,&nbsp;Thierry Allard ,&nbsp;Nicolas Menguy ,&nbsp;Corentin Le Guillou ,&nbsp;Alexandra Courtin ,&nbsp;Cécile Quantin ,&nbsp;Delphine Vantelon ,&nbsp;David Troadec ,&nbsp;Laurence Galoisy ,&nbsp;Georges Calas","doi":"10.1016/j.oregeorev.2024.106321","DOIUrl":"10.1016/j.oregeorev.2024.106321","url":null,"abstract":"<div><div>The Madeira deposit is a world-class tin (Sn) deposit characterized by a unique mineralogical assemblage composed of a massive cryolite (NaAlF₃) deposit associated with economically important metals like Nb (0.20 wt% Nb₂O₅). Although hydrothermal alteration has long been recognized in the cryolite formation, its effects on the mineralization and mobility of Nb remain obscure. This study presents new data on the Nb mineralization of the Pitinga core and border albite-enriched granites provided by nanoscale and site-selective approaches, using transmission electron microscopy and synchrotron-radiation analyses. Pyrochlore is the main Nb ore mineral with three distinct compositional types (U-Pb, Pb-U and Y-bearing varieties). Hydrothermal processes lead to the extensive alteration of pyrochlore into columbite (later designated as columbitization) by a coupled dissolution-reprecipitation mechanism, which evidences the alterability of pyrochlore in a hydrothermal context. Nanoscale analyses of veins and reaction interfaces reveal the presence of additional Nb hosts including fergusonite-(Y), Nb-bearing uraninite and Nb-bearing coffinite which formed from the alteration of pyrochlore. The nature of the altered phases mainly depends on the composition of the parent pyrochlore. Their formation, occurring in absence of direct proximity with remaining pyrochlore, shows that Nb mobilization at macroscopic scale is possible in F-rich reducing fluids. Niobium L₃-edge XANES spectroscopy on bulk samples representative of the different facies show that hydrothermal processes change the Nb mineralization by converting primary U-Pb-bearing pyrochlore into columbite and Pb-U/Y-bearing pyrochlores. The columbitization process of pyrochlore led to the increase of the Nb ore grade. Nonetheless, hydrothermal alteration modified Nb mineral liberation, thereby limiting the recovery of the full range of Nb host phases.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"174 ","pages":"Article 106321"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586144","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}

{"title":"Petrological, mineralogical, carbonate C-O and sulfide S isotope study of the Bayinqinggeli sandstone-hosted uranium deposit in the northern Ordos Basin","authors":"Xiaowen Hu ,&nbsp;Mingxing Ling ,&nbsp;Jianbing Xu ,&nbsp;Qing Gong ,&nbsp;Xiaoyong Yang ,&nbsp;Huaming Li ,&nbsp;Chao Lu ,&nbsp;Zhencheng Li ,&nbsp;Longhui Wang ,&nbsp;Zhiyong Ren ,&nbsp;Tao Guo ,&nbsp;Yujie Hu ,&nbsp;Gaofeng Du ,&nbsp;Wei Xie ,&nbsp;Yijun Feng","doi":"10.1016/j.oregeorev.2024.106334","DOIUrl":"10.1016/j.oregeorev.2024.106334","url":null,"abstract":"<div><div>Many sandstone-hosted uranium deposits have been discovered in the northern Ordos Basin, including the Bayinqinggeli deposit, exhibiting tremendous potential for uranium exploration and prospecting. This region is characterized by complex fluid activities, yet unknowns or controversies still exist regarding the source and properties of the fluids and their influence on uranium mineralization. In this study, we employed optical and scanning electron microscopy (SEM), X-ray diffraction (XRD), micro X-ray fluorescence (μ-XRF), C-O isotope of calcite, and <em>in situ</em> S isotope of pyrite, to investigate the genesis and evolution of the Bayinqinggeli deposit. Pyrite and calcite are closely associated with uranium minerals, and all exhibit distinct characteristics in rocks of varying grades. In high-grade mineralized rocks, ore-related pyrite, characterized by euhedral and colloidal forms, mainly predated uranium mineralization, evidenced by the extensive coffinite replacement. The mostly negative δ³⁴S values with a broad range (−24.6 ‰ to 23.9 ‰; mean = −4.2 ‰) point to microbial sulfate reduction under restricted conditions. In low-grade and barren rocks, pyrite unrelated to mineralization, mainly as large granular or colloidal cement, shows generally positive δ³⁴S values with a wide range (−49.5 ‰ to 67.4 ‰; mean = 15.3 ‰). This suggests the involvement of both biological and abiological processes during different stages, with the latter possibly associated with deep-sourced fluids. Considering the heterogeneous isotope compositions of sulfur in pyrite and carbon in calcite (δ¹³C ranging from −21.4 ‰ to −4.9 ‰), it can be deduced that the deposit was strongly affected by two types of fluids: (1) surface oxidizing fluids and (2) deep reducing fluids. The mineralizing fluids were derived from oxidizing surface water, which dissolved uranium ions, carbonates, and sulfates from weathered source rocks and during infiltration through the sandstone, resulting in the formation of abundant uranium minerals and associated pyrite and calcite. The presence of low δ¹³C calcite further corroborates the influence of deep hydrocarbon-bearing fluids, which played a protective role in post-ore stage preservation, corresponding to the widespread green alteration in the Lower Zhiluo formation. Overall, the development of sandstone-hosted uranium deposits is a continuous and progressive process, with early-formed mineralization being transformed by late-stage fluid events. Calcite has a significant impact on the formation, development, and extraction of uranium ores in the deposit, protecting the paleo-orebodies against remobilization and remigration. A significant portion of uranium ore is preserved by calcite cementation. Therefore, the careful management of carbonates during <em>in situ</em> leaching is essential for the effective extraction of uranium from the host sandstones.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"174 ","pages":"Article 106334"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651228","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}

{"title":"Translating mineral systems criteria into a prospectivity model for IOCG deposits in the Kolari region, Finland","authors":"Fereshteh Khammar ,&nbsp;Vesa Nykänen ,&nbsp;Christoph Beier ,&nbsp;Tero Niiranen","doi":"10.1016/j.oregeorev.2024.106326","DOIUrl":"10.1016/j.oregeorev.2024.106326","url":null,"abstract":"<div><div>The mineral system approach facilitates mapping the fingerprints of geological processes in ore formation using mineral prospectivity modeling (MPM). It aims to reduce the time and cost of exploration as a priority in the mineral exploration industry. Finland, which is covered with thick soil, dense vegetation, and snow in winter and thus has limited outcrops, serves as a suitable testing ground for this method. In this contribution, MPM was employed to predict favorable targets for Fe-Cu-Au (IOCG) deposits in the Kolari region, northwestern Finland. The mineral system components ore metal and sulfur sources, pathways, energy sources/drivers, traps, and the geological factors influencing the ore-forming processes were translated into mappable criteria and were considered for a regional-scale analysis. Knowledge-driven, fuzzy logic overlay, fuzzy inference system, and geometric average methods integrate evidential layers derived from geological (scale-free geology map), geochemical (till and bedrock sample geochemistry), and geophysical data (magnetic, radiometric, electromagnetic measurements, and gravity worms). Subsequently, the data were modeled using a combined conceptual/empirical approach, i.e. fuzzified evidential layers and logistic regression. In the prospectivity models, existing IOCG deposits are consistently placed within high-favorability areas. In addition, new exploration targets were identified. The models were validated against known IOCG deposits using Receiver Operating Characteristic (ROC) analysis and average Area Under the Curve (AUC) with values of final prospectivity models consistently reaching scores &gt; 0.8. This indicates a favorable outcome of the application of MPM, making the approach applicable to other regions and ore deposit types. A majority voting ensemble technique was employed to combine the favorable areas of each prospectivity model. Then a confidence index was adopted reducing uncertainty linked to the models generated. These outputs consistently facilitated the identification of exploration targets more reliably.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"174 ","pages":"Article 106326"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651309","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}

{"title":"Crystallographic insights and crystal fractionation simulations of alkali- and water-bearing beryl: Implications for magmatic–hydrothermal evolution and Be enrichment mechanisms","authors":"Zhi-Wei Fan ,&nbsp;Yi-Qu Xiong ,&nbsp;Matthew J. Brzozowski ,&nbsp;Yong-Jun Shao ,&nbsp;Xiang-Ping Gu ,&nbsp;Mohamed Anwar ,&nbsp;Sobhi M. Ghoneim","doi":"10.1016/j.oregeorev.2024.106278","DOIUrl":"10.1016/j.oregeorev.2024.106278","url":null,"abstract":"<div><div>Beryl, an economically significant mineral containing high concentrations of the critical metal Be, has been the subject of considerable characterization regarding its crystal structure and chemical composition. Despite this, discerning between alkali- and H₂O-bearing beryls solely based on the alkali and water contents within the structural channels of beryl has remained a challenge. Additionally, the mechanisms that cause granitic melts to become enriched in Be remain ambiguous. Through comprehensive chemical and structural analyses of representative alkali-water-bearing beryl samples from Igla of East Egypt and Baishawo of South China, this contribution improves the beryl classification model and provides new perspectives on Be enrichment mechanisms. This analysis has demonstrated that a linear correlation exists between the water content and alkali content of hydrous beryls, and identified two distinct types of H₂O molecules — Type I and II. Major elements are uniformly distributed throughout beryl grains, whereas trace elements exhibit core–rim zonation. Crystal–chemical characteristics of alkali- and water-bearing beryls provide valuable insights into pegmatite evolution, with implications for understanding mineralizing processes and formation conditions. The distributions of alkali metals, Mg, Mn and Fe in alkali-rich and H₂O-rich (ARHR) beryl suggest that the pegmatite in the beryl-bearing zones is the product of magmatic metls. Low Fe/Mg ratios of alkali-poor and H₂O-rich (APHR) beryl are associated with hydrothermal alkali-metasomatism. Using the Baishawo Be–Li–Nb–Ta pegmatite deposit as a case study, we utilize crystal fractionation simulations to demonstrate the alkali- and water-bearing beryls crystallized after high degrees of magma evolution. The study contributes to the classification of beryl varieties based on chemistry and structure, and provides new insights into Be enrichment mechanism in granitic melts and hydrothermal fluids.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"174 ","pages":"Article 106278"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142553565","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}