Ore Geology Reviews最新文献

{"title":"Polyphase deformation history and its structural controls on auriferous quartz vein stockwork in the Xiaoqinling district, southern margin of the North China Craton","authors":"Yunjian Li ,&nbsp;Guang Zhu ,&nbsp;Jin Liu ,&nbsp;Keke Sun ,&nbsp;Chengchuan Gu ,&nbsp;Menglong Dong ,&nbsp;Jianhua Yan ,&nbsp;Chao Li ,&nbsp;Fei Xue ,&nbsp;Cheng Liu ,&nbsp;Shuai Zhang","doi":"10.1016/j.oregeorev.2024.106379","DOIUrl":"10.1016/j.oregeorev.2024.106379","url":null,"abstract":"<div><div>“Structural control” is a crucial point in revealing the genesis mechanism and distribution patterns of vein-type gold deposits. Being the second largest gold producer in China, the Xiaoqinling region has experienced complex and polyphase structural deformations. However, the persistent absence of research on the regional structural deformation sequences and superimposed relationships have posed significant challenges to understanding the ore-controlling structural model, timing of gold mineralization, and dynamic mechanisms. In this contribution, we established an Early Paleoproterozoic to Late Mesozoic structural deformational-event framework (D₁–D₅) and proposed an ore-controlling structural model by integrating an analysis of the geometry, kinematics, overprinting, and crosscutting relationships of structures at different deformation events, the spatial coupling relationship between gold veins and structures with various orientations, and prior geochronological data. The D₁–D₄ deformation structures initially established the EW–NW, NE and NS-oriented pre-existing ore-controlling structures framework. The reactivation of pre-existing structures (D₁–D₄) during the D₅ deformation event (gold mineralization period), concurrently giving rise to new NE-trending extensional structures accompanying the tectonic evolution of the metamorphic core complex (MCC), collectively created a multi-directional structural network connecting mineralizing fluids to structural traps, within which auriferous quartz veins emplaced, and displaying a phenomenon of multi-directional intertwining. Combined with previous studies, new structural analysis showing that gold mineralization in the Xiaoqinling area falls within the Early Cretaceous, peaking at 126 Ma, aligning with the timing of rapid crustal uplift, generated in a backarc extension setting induced by the roll-back following the flat subduction of the Paleo-Pacific slab. Our study highlights the crucial role of reactivated pre-existing structures in controlling gold mineralization, demonstrating that structural deformation analysis is essential for understanding the genesis and mechanisms of complex gold district, and suggests that the ductile–brittle shear zones trending in both E–W and NE directions within the middle part of the Xiaoqinling district are crucial positioning areas for exploration of deep-seated gold deposits.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"175 ","pages":"Article 106379"},"PeriodicalIF":3.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747874","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":"Short wavelength infrared (SWIR) spectral and geochemical characteristics of white micas in the Xiaonangou gold deposit, East Qinling: As a hyperspectral tool in exploration","authors":"Mengqi Wang ,&nbsp;Jingwen Mao ,&nbsp;Zuoman Wang ,&nbsp;Guolong Yan ,&nbsp;Shufei Liu ,&nbsp;Haoyuan Jiang ,&nbsp;Yongfei Tian ,&nbsp;Peng Wang ,&nbsp;Gang Chen ,&nbsp;Guang Miao ,&nbsp;Huishou Ye","doi":"10.1016/j.oregeorev.2024.106349","DOIUrl":"10.1016/j.oregeorev.2024.106349","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The Xiaoqinling-Xiong’ershan region, a prominent component of the East Qinling Belt, is renowned worldwide for its molybdenum and gold ore fields. Moreover, with gold reserves of at least 1300 tons, it is also China’s major gold mining province, second only to Jiaodong. Seated in eastern center of the Xiong’ershan area, the Xiaonangou gold deposit has an estimated gold reserve of over 60 tons and is characterized by disseminated gold in altered rocks. Based on detailed petrographic investigation, coupled with an analysis of crosscutting relationships, there are three stages of hydrothermal alteration and mineralization: pre-ore K-feldspar + quartz (stage Ⅰ), ore quartz + ankerite + disseminated pyrite + polymetallic sulfide (stage Ⅱ), and post-ore quartz + carbonate (stage Ⅲ). As revealed by a systematic analysis of short wavelength infrared (SWIR) spectroscopy, four main types of alteration minerals exist, including white micas, clay minerals, chlorite, and carbonate minerals. In the ore body, white micas mainly developed in stage Ⅱ, and slightly occurred in stage Ⅰ. The clay minerals and chlorite usually developed in the banded alteration zones outside the orebody. Most of the carbonate minerals, including calcite and dolomite, mainly developed in stage Ⅲ, but the ankerite was associated with disseminated pyrite, quartz and polymetallic sulfides in stage Ⅱ. Of these, white micas were recognized as the most abundant hydrothermal alteration minerals, which were observed to be widely distributed within alteration zones in the Xiaonangou gold deposit. The SWIR parameters and its spatial variation of white mica indicate that the Al-OH absorption positions (Pos2200) exhibit a drifting tendency towards longer (&gt;2205 nm) wavelengths in the ore body vicinity. Additionally, there is a discernible increase in illite crystallinity (IC values) in the same region. The temperature, redox, and pH conditions for associated fluids can be reflected through characterization of these parameters. Furthermore, it demonstrates that the ore-proximal zones are situated in a relatively oxidized, alkaline, and high-temperature environment in the Xiaonangou gold deposit. According to the electron probe microanalysis (EPMA) results, two distinct end members exist in white mica: a Si-poor, Al-rich muscovite and an Al-poor, Si-, Fe-, and Mg-rich phengite. The Si, &lt;sup&gt;iv&lt;/sup&gt;Al, &lt;sup&gt;vi&lt;/sup&gt;Al, Mg, Fe, and Ti elements exhibit a linear correlation with the wavelength of Pos2200, demonstrating that the shift in wavelength of white mica is predominantly controlled by Tschermak substitution (&lt;sup&gt;iv&lt;/sup&gt;Si&lt;sup&gt;vi&lt;/sup&gt;(Mg，Fe) ↔&lt;sup&gt;iv&lt;/sup&gt;Al&lt;sup&gt;vi&lt;/sup&gt;Al). The application of spatial variation in the SWIR spectral parameters along with geochemical properties of white mica facilitates the effective guidance of mineral exploration. In comparison to other deposits, it can be concluded that the longer (&gt;2205 nm) wavelength of the Pos2200 along with the higher IC ","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"175 ","pages":"Article 106349"},"PeriodicalIF":3.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747853","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":"Ore-forming process of the Saibagou gold deposit in the Northern Qaidam Orogen: Evidence from fluid inclusions, D-O isotopes and pyrite geochemistry","authors":"Mingying Tang ,&nbsp;Zhengjiang Ding ,&nbsp;Xuanxuan Li ,&nbsp;Wei Zhu ,&nbsp;Honglei Zhan ,&nbsp;Qibin Zhang ,&nbsp;Xin Wang ,&nbsp;Lei Hua ,&nbsp;Lisha Sun","doi":"10.1016/j.oregeorev.2024.106368","DOIUrl":"10.1016/j.oregeorev.2024.106368","url":null,"abstract":"<div><div>The northern Qaidam Orogen that hosts over 100 gold deposits is an important gold mineralization belt in Qinghai Province (western China). However, ore-forming processes and genesis of these gold deposits remain controversial. We analyzed the fluid inclusions (FIs), D-O isotopes and pyrite trace element compositions of the Saibagou gold deposit in the Tommorrit-Saibagou area and discussed the genesis of this deposit. These results show that the Saibagou gold ores contain three types of FIs: aqueous, aqueous-CO₂, and pure CO₂ type. The ore-forming fluids in each stage changed from an early medium temperature and low-salinity H₂O-NaCl ± CO₂ system to a late low-temperature and low-salinity H₂O-NaCl system. The D-O isotopes show that the ore-forming fluids are the mixed fluids of metamorphic water and meteoric water. In the main-ore stage, the ore fluids are mainly metamorphic and minor magmatic water sourced, with increasing meteoric water incursion toward the late-ore stage. The Au and other ore-forming elements (such as Ag, Cu, Pb, Zn, Te) are positively correlated and are mainly enriched in pyrite in the stage II. We suggest that the Saibagou is an orogenic gold deposit and is closely related to the Late Silurian northward subduction and hyperplastic orogenesis in Qaidam Block.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"175 ","pages":"Article 106368"},"PeriodicalIF":3.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747845","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":"Shortwave infrared (SWIR) spectroscopy for greenfield exploration: Investigating the Bayi-Muchang prospect within the Jiama giant Porphyry-Skarn system","authors":"Junfeng Zhao ,&nbsp;Yabo Zhu ,&nbsp;Wanjian Lu ,&nbsp;Bing Xiao ,&nbsp;Zhengkun Yang ,&nbsp;Liang Du","doi":"10.1016/j.oregeorev.2024.106369","DOIUrl":"10.1016/j.oregeorev.2024.106369","url":null,"abstract":"<div><div>Jiama is a giant porphyry-skarn system (1,814 Mt ore @ 0.40 % Cu) within the Gangdese porphyry copper belt, Southern Tibet. Recently, copper, molybdenum, and tungsten anomalies, similar to those at Jiama, have been identified in the Bayi-Muchang prospect southwest of the deposit. However, the mineralization potential of this peripheral area and its genetic connection to Jiama remain poorly constrained. This study employs shortwave infrared (SWIR) spectroscopy to map alteration minerals in both the Bayi-Muchang prospect and compare them to those in the southwestern Jiama deposit. SWIR spectral results reveal that the Bayi-Muchang prospect is dominated by chlorite, phengite, quartz, and less carbonates from chlorite-sericite alteration with minor epidote and chlorite vein-halos, as well as pervasive propylitic assemblages with chlorite, epidote, and less carbonates, indicating the presence of an independent hydrothermal center where ore-forming fluids were concentrated and exsolved rather than an extension of the Jiama deposit. Key spectral indicators for mineralized zones, derived from Jiama samples, including wavelength of 2200 nm feature longer than 2207 nm and the illite spectral maturity higher than 1.4 in white mica, as well as the full width at half maximum (FWHM) of 2335 nm feature longer than 36 nm in carbonate minerals. Additionally, carbonate minerals in the Duodigou Formation north of Bayi-Muchang record a contact metamorphism gradient, with the FWHM of the 2335 nm feature increasing from 36 to 56 nm from south to north. The northwest Bayi-Muchang area, near the hydrothermal center, is identified as a favorable target for skarn-type and porphyry-type mineralization. This study highlights the effectiveness of SWIR spectroscopy mapping in supporting exploration strategies within porphyry-skarn systems, particularly for greenfield targets.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"175 ","pages":"Article 106369"},"PeriodicalIF":3.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747849","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":"Machine learning for deciphering ore-forming fluid sources using scheelite trace element geochemistry","authors":"Hongtao Zhao ,&nbsp;Mingrui Liu ,&nbsp;Yu Zhang ,&nbsp;Yongjun Shao ,&nbsp;Zequn Yu ,&nbsp;Genshen Cao ,&nbsp;Lianjie Zhao ,&nbsp;Yongshun Li","doi":"10.1016/j.oregeorev.2024.106374","DOIUrl":"10.1016/j.oregeorev.2024.106374","url":null,"abstract":"<div><div>Identifying the source of ore-forming fluids is crucial for constraining ore genesis and guiding exploration. This study introduces a novel approach that leverages the geochemical properties of scheelite and the latest advancements in machine learning algorithms to decipher ore-forming fluid sources. A variety of supervised machine learning methods, including Decision Tree, Random Forest, Multilayer Perceptron, Extreme Gradient Boosting (XGBoost), Light Gradient Boosting Machine (LightGBM), k-Nearest Neighbors, and Logistic Regression, are employed to identify the source of scheelite ore-forming fluids using high-dimensional information of scheelite trace element data. This study demonstrates that XGBoost (accuracy: 93.5%, AUC: 98.8%) and LightGBM (accuracy: 93.2%, AUC: 98.6%) classifiers efficiently and accurately classify high-dimensional trace element data of metamorphic-hydrothermal and magmatic-hydrothermal scheelite. Interpretation of the models using the SHapley Additive exPlanations tool reveals that Sr, La, Eu, Nb, Pb, Ta, and Mo of scheelite are the most indicative elements for predicting ore-forming fluid sources. Additionally, the discrimination of scheelite data by the XGBoost and LightGBM algorithms suggests that the Darongxi W, Muguayuan W, Yangjiashan Au–Sb–W, and Longshan Au–Sb–W deposits in the Xiangzhong metallogenic province (XZMP, South China) are likely magmatic-related, while the Daping Au, Woxi Au–Sb–W, and Zhazixi Au–Sb–W deposits are likely orogenic. This reveals the complexity of regional Au–Sb–W mineralization in the XZMP. Importantly, this research highlights the untapped potential of integrating scheelite trace element geochemical data with explainable machine learning technology to determine ore-forming fluid sources.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"175 ","pages":"Article 106374"},"PeriodicalIF":3.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747848","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":"Scheelite texture and composition fingerprint skarn mineralization of the giant Yuku Mo-W deposit, Central China","authors":"Fan Yu ,&nbsp;Qihai Shu ,&nbsp;David R. Lentz ,&nbsp;Qingfei Wang ,&nbsp;Rongzhen Zhang ,&nbsp;Xudong Niu ,&nbsp;Qingwen Zeng ,&nbsp;Kai Xing ,&nbsp;Jun Deng","doi":"10.1016/j.oregeorev.2024.106361","DOIUrl":"10.1016/j.oregeorev.2024.106361","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Scheelite is widely used to reveal ore-forming redox environments and track hydrothermal evolution processes in W-bearing deposits. Yuku, situated in Central China, is a typical skarn Mo-W deposit discovered recently in the Luanchuan Mo-W-Zn-Pb ore district. This study determined the compositions of the Yuku scheelite via laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and electron microprobe analysis (EMPA) techniques. Based on the textural characteristics and mineral assemblages, three types of scheelite were categorized, including Sch A1, Sch A2, and Sch B. In general, Sch A1 formed during the prograde stage, mostly occurring as euhedral grains that distributed discretely within the interstices of skarn minerals. Sch A2 predominantly formed as the rim of Sch A1 or crosscut Sch A1. It is commonly associated with sulfides, such as pyrrhotite, pyrite, and molybdenite. Sch B is primarily observed in the quartz-sulfide veins or within pyrrhotite crystals, occurring later than Sch A1 and Sch A2. Geochemically, Sch A1 contains a significantly higher Mo content (&gt;14,300 ppm) and is characterized by a negative inclined chondrite-normalized rare earth element (REE) pattern, while Sch B has Mo contents lower than 10,300 ppm and exhibits an M-type tetrad REE pattern. Sch A2 contains a Mo content ranging from 146 ppm to 89,000 ppm (mean 27,900 ppm) and displays an intricate REE pattern that partially overlaps with Sch A1 and Sch B. The difference of REE concentrations among different scheelite generations is controlled by substitution mechanisms and also influenced by the precipitation of garnet and pyroxene. Sch A1 and Sch B exhibit a linear 1:1 trend between Na (atom) and ΣREE – Eu + Y (atom), indicating the important role of substitution via 2Ca&lt;sup&gt;2+&lt;/sup&gt; = REE&lt;sup&gt;3+&lt;/sup&gt; + Na&lt;sup&gt;+&lt;/sup&gt;. The concentrations of Nb, Ta and V are notably low, supporting only a small amount of REE incorporation into Sch A1 through Ca&lt;sup&gt;2+&lt;/sup&gt; + W&lt;sup&gt;6+&lt;/sup&gt; = REE&lt;sup&gt;3+&lt;/sup&gt; + (Nb + Ta + V)&lt;sup&gt;5+&lt;/sup&gt;. The REE patterns of Sch A1 and partly Sch A2 resemble those of the causative intrusions, indicating that substituting the site vacancy in scheelite lattice is another crucial mechanism. All three substitution mechanisms play roles in REE incorporation during the scheelite mineralization process. Negative Eu anomalies prevail in Yuku scheelite (mean δEu = 0.77), although positive Eu anomalies are also observed, particularly in Sch B (mean δEu = 1.11). Additionally, there is a conspicuous decreasing trend in the Mo content from the prograde to late stage, suggesting that the Mo-W mineralization at Yuku likely experienced a decrease in oxygen fugacity and/or temperature. Furthermore, in a comparative analysis of scheelite Mo content and Eu anomaly with other deposits, it was observed that Mo content in skarn deposits is generally higher than that in orogenic deposits (mostly &lt;100 ppm), providing a tool for distinguishing dep","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"175 ","pages":"Article 106361"},"PeriodicalIF":3.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747851","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":"Petrogenesis and Sc mineralization potential of the early Silurian Halaguole Alaskan-type complex in the East Kunlun orogenic belt","authors":"Lingyun Sun ,&nbsp;Xiaoliang Li ,&nbsp;De Yang ,&nbsp;Jien Dong ,&nbsp;Xiaoliang Yu ,&nbsp;Hua Li ,&nbsp;Ye Qian ,&nbsp;Chao Wang ,&nbsp;Fengyue Sun","doi":"10.1016/j.oregeorev.2024.106354","DOIUrl":"10.1016/j.oregeorev.2024.106354","url":null,"abstract":"<div><div>The Alaskan-type complexes are known for their unique annular lithologic zoning structure and are products of an island arc environment. The Halaguole mafic–ultramafic intrusions in the Kunlun orogenic belt, as reported in this study, exhibit characteristics of an Alaskan-type complex. The complex is composed of peridotite, pyroxenite, and gabbro, with well-defined annular lithological zoning from the core to the margin. The Halaguole mafic–ultramafic intrusions were formed during the Early Silurian period, specifically ranging from 437 Ma to 440 Ma according to Zircon LA-ICP-MS U-Pb dating results. They are enriched in large ion lithophile elements (LILE) and depleted in high field strength elements (HFSE), revealing positive europium (Eu) anomalies and negative niobium (Nb) anomalies. All of these characteristics indicate that they are products of an island arc environment. Based on analysis of zircon’s εHf(t) value (0.25 to 5.14) and model age (TDM1) (842.19 to 1034.61 Ma), it can be deduced that the intrusions originated from an enriched mantle source. The dominant mineral compositions within the Halaguole intrusions include olivine, clinopyroxene, amphibole, biotite, and spinel. With the absence of orthopyroxene, the compositions of these minerals are similar to Alaskan-type complexes. The contents of olvine, biotite, and spinel suggest that the parental melt of these intrusions is an aqueous basaltic magma with island arc properties. The Halaguole mafic–ultramafic intrusions likely formed through partial melting of the mantle wedge metasomatized by fluids from the subduction zone. This process was accomplished by fractional crystallization of magma. Combining the findings of previous research with the evidence presented in this study, it can be deduced that the closure of the Proto-Tethys Ocean occurred during the Early Silurian. Furthermore, it is evident that the Wanbaogou basaltic plateau in the Southern Kunlun Belt (SKB) underwent bidirectional subduction in a north–south direction. Notably, the samples from pyroxene peridotite and gabbro exhibit a significant concentration of Sc, ranging from 41.5 to 224.5 ppm, exceeding industrial grade levels and indicating excellent potential for Sc mineralization.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"175 ","pages":"Article 106354"},"PeriodicalIF":3.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747852","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":"Genesis of Cu deposits hosted by volcanic rocks in Yunxian-Jinggu Arc, Western Yunnan: Constraints from fluid inclusions and C-O-S isotopes","authors":"Xu Zheng ,&nbsp;Xiang Sun ,&nbsp;Bin Fu ,&nbsp;Qiang Li ,&nbsp;Ke Xiao","doi":"10.1016/j.oregeorev.2024.106362","DOIUrl":"10.1016/j.oregeorev.2024.106362","url":null,"abstract":"&lt;div&gt;&lt;div&gt;A series of vein-type Cu deposits have been preserved in the Triassic volcanic rocks of the Yunxian-Jinggu area. The Guanfang, Bazijie, and Minleyichang deposits are typical examples of regional Cu mineralization. The deposits are preserved in the intermediate-basic volcanic rocks, and the ore bodies are controlled by NNE-trending structures with similar alteration features and mineral assemblages. The fluid inclusions are recognized in quartz and calcite at the three deposits, dominated by aqueous inclusions (L) and liquid phase-rich vapor–liquid two-phase inclusions (L-V) with similar temperature (270-140℃) and salinity (14.0–20.2 wt% NaCl eq.). The three deposits have a medium–low temperature, moderate salinity, and higher oxidation rate than the volcanic host rocks, confirmed by the fluid inclusion, alteration, and mineral assemblage. The O isotope values for early quartz associated with sulfides in the three deposits are comparable (δ&lt;sup&gt;18&lt;/sup&gt;O&lt;sub&gt;SMOW&lt;/sub&gt; = 15.23 to 20.01 ‰). Late quartz in the Guanfang and Bazijie deposits shows a deficit in O isotope values compared to early quartz (δ&lt;sup&gt;18&lt;/sup&gt;O&lt;sub&gt;SMOW&lt;/sub&gt; = 9.89 to 13.98 ‰), indicating the incorporation of meteoric water or basin fluid during the late stage of mineralization. The early calcite in the Guanfang and Bazijie deposits have similar C-O isotopic signatures (δ&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;V-PDB&lt;/sub&gt; = −10.51 to −4.75 ‰, δ&lt;sup&gt;18&lt;/sup&gt;O&lt;sub&gt;V-SMOW&lt;/sub&gt; = 11.29 ‰ to 12.63 ‰), and δ&lt;sup&gt;18&lt;/sup&gt;O&lt;sub&gt;fluid&lt;/sub&gt; (3.84 to 5.18 ‰) calculated from calcite is approximately the same as the δ&lt;sup&gt;18&lt;/sup&gt;O&lt;sub&gt;fluid&lt;/sub&gt; (2.08 to 3.95 ‰) calculated from early quartz. The early calcite and early quartz in the Guanfang and Bazijie deposits may be connected to the same fluid source based on the similar δ&lt;sup&gt;18&lt;/sup&gt;O&lt;sub&gt;fluid&lt;/sub&gt; signatures and salinities. The calcite C-O isotopic compositions of the Minleyichang deposit are &lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;V-PDB&lt;/sub&gt; = −23.03 to −17.74 ‰ and δ&lt;sup&gt;18&lt;/sup&gt;O&lt;sub&gt;V-SMOW&lt;/sub&gt; = 19.72 to 28.32 ‰, which exhibit the characteristics of biogenic carbon and indicate that the material originated from sedimentary layers in the Simao Basin. The sulfide δ&lt;sup&gt;34&lt;/sup&gt;S&lt;sub&gt;V-CDT&lt;/sub&gt; ranges from −17.2 to 3.2 ‰ in the three deposits, which is related to the addition of reduced S from the sedimentary strata in the Simao Basin. The fluid characteristics of medium to low temperature, moderate salinity, and the S-C isotope signatures indicate that the ore-forming fluids are the basin brine from the Simao Basin. The Cu mineralization in the Yunxian-Jinggu area is closely related to the thrust-fold structure system formed during the Late Cretaceous to the Cenozoic period. The ore-forming fluids may have come from the brine in the central part of the Simao Basin, which migrated through the thrust fault and assimilated the materials in the regional volcanic rocks and sedimentary rocks, forming Cu deposits in the Triassic volcanic rocks of Yunxian-Jingg","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"175 ","pages":"Article 106362"},"PeriodicalIF":3.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757167","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":"Deep learning-based mineral exploration named entity recognition: A case study of granitic pegmatite-type lithium deposits","authors":"Jintao Tao ,&nbsp;Nannan Zhang ,&nbsp;Jinyu Chang ,&nbsp;Li Chen ,&nbsp;Hao Zhang ,&nbsp;Shibin Liao ,&nbsp;Siyuan Li","doi":"10.1016/j.oregeorev.2024.106367","DOIUrl":"10.1016/j.oregeorev.2024.106367","url":null,"abstract":"<div><div>Geological text data play a crucial role as sources of geological information and knowledge for mineral exploration. Mineral exploration involves predicting and detecting mineral resources using geological, geochemical, geophysical, and remote sensing data. However, existing named entity recognition studies on mineral deposits have mainly focused on geological environments and mineral deposit models, which are insufficient for capturing the extensive knowledge essential for mineral exploration and supporting subsequent exploration efforts. This paper presents an efficient workflow for automatically extracting mineral exploration information from unstructured geological text data using a deep learning method. Initially, 21 entity types were identified based on a conceptual prospecting model of granitic pegmatite-type lithium deposits. A mineral exploration corpus was constructed from Chinese geological literature and reports, comprising 3,386 sentences and 13,167 entities. Subsequently, a Mineral Exploration Named Entity Recognition (MENER) model is proposed to extract mineral exploration information. This model integrates entity-type enhanced characters, words, and contextual features to enhance the performance. Bidirectional encoder representations from the transformer model were employed to obtain character embeddings of the input text. Mineral exploration entity types provide external knowledge, aiding the understanding of entity semantics within sentences through multi-head attention. Convolutional neural networks and bidirectional long short-term memory models have been employed to extract word and contextual features and capture additional structural information. Geological entity nomenclature and expressions follow certain default conventions and paradigms. A boundary prediction classifier was introduced to identify the head and tail characteristics of geological entities. A conditional random field was then utilized to classify the entities. The MENER model achieved an average F1-score of 79.69% on the constructed dataset. Finally, a geological document was selected as a case study to demonstrate the effectiveness of the proposed model. The workflow outlined in this study enables the rapid and robust extraction of specific information and knowledge mining from geological text data, with potential applications across various domains.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"175 ","pages":"Article 106367"},"PeriodicalIF":3.2,"publicationDate":"2024-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723914","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":"Olivine Ni isotopes of Ni-Cu deposits in northwest China: A potential sulfide segregation indicator in basaltic magmatic systems","authors":"Ya-Jing Mao ,&nbsp;Shui-Jiong Wang ,&nbsp;Min Li ,&nbsp;Ben-Xun Su ,&nbsp;Xin-Yi Li ,&nbsp;Xu-Yang Zheng ,&nbsp;Ke-Zhang Qin","doi":"10.1016/j.oregeorev.2024.106364","DOIUrl":"10.1016/j.oregeorev.2024.106364","url":null,"abstract":"<div><div>Sulfide segregation from silicate magmas is essential in forming magmatic sulfide deposits, but a robust Ni isotopic indicator has been lacking. This study investigates the Ni isotopic compositions of olivine and coexisting sulfide from three magmatic Ni-Cu deposits in East Tianshan, northwest China, to reveal the behavior of Ni isotopes during magmatic differentiation and sulfide segregation processes. The <em>δ</em>^60/58Ni values in olivine separates (+0.15 to +0.68 ‰, median 0.40 ‰) are notably higher than typical mantle and basalt values (+0.11 to +0.23 ‰). Decreased Ni at the rim of Fe-Mg unzoned olivine indicates certain degrees of post-crystallization Fe-Ni diffusion between sulfide and olivine. The intragrain diffusion modeling results show that the <em>δ</em>^60/58Ni values in olivine can change up to 0.5 ‰ to 1 ‰ when the diffusional modification of Ni extends to the core. However, the observed thin Ni gradient at the rim and relatively flat Ni profiles in the cores of the olivine samples suggest limited kinetic modifications. Moreover, the <em>δ</em>^60/58Ni values negatively correlate with the Ni content and Ni/Co ratio in olivine. The sulfide separates are isotopically lighter than the coexisting olivine grain, with <em>δ</em>^60/58Ni_olivine – <em>δ</em>^60/58Ni_sulfide values ranging from +0.10 to +0.40 ‰ (median +0.22 ‰). Given limited Ni isotope fractionation between olivine and silicate melt, the observed Ni isotopic differences between olivine and sulfides are attributed to Ni isotope fractionation between silicate melt and sulfide melt at magmatic temperatures, efficiently incorporating isotopically light Ni into the sulfide melt. The sulfide segregation-driven Ni isotope fractionation aligns with the distinct Ni isotopic compositions observed in olivine grains from two highly differentiated mafic units of the Huangshandong deposit with different sulfide evolution histories. Olivine grains from mineralized gabbronorite have higher <em>δ</em>^60/58Ni values (+0.68 ‰, Phase III) than those from sulfide-barren olivine gabbro (<em>δ</em>^60/58Ni = +0.23 ‰, Phase I). Systematic stratigraphic Ni isotope variations in the Huangshanxi olivine from intervals with varying degrees of sulfide segregation and magma replenishment further support this interpretation. These findings demonstrate that Ni isotopes in olivine are reliable for tracing sulfide segregation, provided that diffusional modification is carefully assessed. With limited diffusional modification, the widespread isotopically heavy Ni signature in olivine (<em>δ</em>^60/58Ni &gt; 0.3 ‰) serves as a valuable indicator for sulfide segregation and exploring magmatic<!--> <!-->Ni-Cu deposits.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"175 ","pages":"Article 106364"},"PeriodicalIF":3.2,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698614","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}