Ore Geology Reviews最新文献

{"title":"Uncover implicit associations among geochemical elements using machine learning","authors":"Shuguang Zhou ,&nbsp;Zhizhong Cheng ,&nbsp;Jinlin Wang ,&nbsp;Nuo Li ,&nbsp;Guo Jiang","doi":"10.1016/j.oregeorev.2025.106506","DOIUrl":"10.1016/j.oregeorev.2025.106506","url":null,"abstract":"<div><div>The production of geochemical data serves diverse purposes, and a variety of analytical methods are utilized for analyzing geochemical element content. However, due to limitations in project funds, censored or missing values are common in geochemical data. This scarcity of data becomes more pronounced when dealing with large datasets. Regrettably, numerous data analysis techniques are unable to process datasets containing missing values, which presents a significant hurdle for researchers who depend on geochemical data. To address this issue, here we employed a random forest model to simulate the geochemical elements of rocks and stream sediments. By comparing and analyzing the effects of model parameters and feature variable selection on the simulation results of major and trace elements, the study found that with appropriate model parameters and variable selection, the simulation results for many elements are reliable, and the generalization performance of the random forest model is satisfactory. This research sheds light on the inherent correlations among various elements in nature, offers solutions to the challenges posed by missing values in geochemical data, and provides valuable technical support for disciplines such as geology, environmental science and soil science.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"179 ","pages":"Article 106506"},"PeriodicalIF":3.2,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454668","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 characteristics of magnetite from the Litun skarn iron deposits in eastern China and its Significance","authors":"Yinan Liu ,&nbsp;Yuzhen Zhu ,&nbsp;Huaihong Wang ,&nbsp;Lijun Shen ,&nbsp;Dongdong Wang ,&nbsp;Xue Liu ,&nbsp;Yunhe Lü","doi":"10.1016/j.oregeorev.2025.106505","DOIUrl":"10.1016/j.oregeorev.2025.106505","url":null,"abstract":"<div><div>The Litun deposit, a recently discovered skarn Fe deposit in eastern China, is hosted within Carboniferous mudstone-detrital rocks and exhibits distinctive mineralization characteristics. This study presents a systematic in-<em>situ</em> trace element analysis of magnetite from the Litun deposit. The Liutun deposit has undergone intense hydrothermal alteration, which can be divided into four stages: skarn (stage I), oxide (stage II), sulfide (stage III), and carbonate (stage IV). Magnetite primarily formed during stage II, co-existing with tremolite, chlorite, epidote, and phlogopite. The analysis reveals that most samples formed under medium to low temperature conditions (Ti + V＜1000 ppm). The concentrations of Mg, Al, and Si in magnetite are strongly influenced by coexisting minerals (tremolite, chlorite, epidote). Within the same drill hole, magnetite proximal to the wall rock commonly exhibits higher Ti and V contents, suggesting that the mineralizing fluid underwent replacement from both deep and shallow sides towards the central part. During the replacement process, the (Si + Al)/(Mg + Mn) ratio range increases, indicating that non-carbonate strata are unable to effectively buffer the fluctuations in fluid composition during mineralization. Most of the analysis points fall in the skarn region in the discriminant diagram. Combined with previous δ³⁴S of pyrite studies, it is inferred that the mineralizing fluid was likely mixed with deep Ordovician marine sedimentary strata. This study demonstrates the significant indicative value of magnetite trace elements for identifying deep-seated hidden carbonate formations. The interface between non-carbonate and carbonate lithologies, particularly when associated with diorite intrusions, represents a promising exploration target for “Litun-type” skarn Fe deposits.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"179 ","pages":"Article 106505"},"PeriodicalIF":3.2,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143463484","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 genesis of gold deposits in the daduhe belt: A Case study of the Lianhua gold deposit on the Western margin of the Yangtze Craton, China","authors":"Hongbin Li,&nbsp;Guochen Dong,&nbsp;Zhuolin Xie,&nbsp;Shuai Wang,&nbsp;Yuting Fan","doi":"10.1016/j.oregeorev.2025.106500","DOIUrl":"10.1016/j.oregeorev.2025.106500","url":null,"abstract":"<div><div>The Daduhe gold belt (DGB) is an essential gold mineralization belts discovered in southwestern China. However, there are still some controversies on the material source, fluid origin and properties. The Lianhua gold deposit, as one of the typical gold deposits in the DGB, is suitable to understand the mineralization. Based on field investigation, and analysis on mineralogy, fluid inclusions, and S-H-O isotope geochemistry, a possible metallogenic model is proposed. According to field observations, the Lianhua deposit has experienced at least two phases of hydrothermal activity, namely, the ore-forming and post-ore periods. Three types of fluid inclusions are identified: 1) V_CO2–L_H2O (C1 type), 2) V_CO2±CH4–L_H2O (C2 type), and 3) V_H2O–L_H2O (W type). The inclusions in ore-forming periods are mainly C1 and C2 type, while the post-ore period is W type predominately. Microthermometric analyses show that ore-forming quartz veins formed in a low to medium temperature (201.6℃–315.2℃), low to medium salinity (3.05–13.20 wt% NaCl eqv.) H₂O–NaCl–CO₂ ± CH₄ system. The H-O isotope of ore-forming quartz shows, the δ¹⁸O_V-SMOW ranged from 7.29 ‰–10.81 ‰, whereas the δD_V-SMOW ranged from − 63.5 ‰–−68.3 ‰, implying that the ore-forming fluids are formed by a mixture of metamorphic fluids and meteoric water. Fluid immiscibility caused by the separation of CO₂ ± CH₄–H₂O system and H₂O–NaCl system may be the main mechanism of gold precipitation. The δ³⁴S values of pyrite ranged from − 3.12 ‰–5.92 ‰, indicating that the Kangding complex provided ore-forming materials.</div><div>The post-ore tourmaline quartz veins formed in a medium to high temperature (286.6℃–460.1℃), medium to high salinity (9.98–20.26 wt% NaCl eqv.) H₂O–NaCl system. The δ¹⁸O_V-SMOW is 9.16 ‰, whereas the δD_V-SMOW is − 85.5 ‰, implying that the post-ore fluids are predominantly primary magmatic water or at least vast magmatic water injection. Tourmaline, as a characteristic mineral of post-ore hydrothermal event, is formed by crustal magmatic fluids reacted with the Kangding complex. However, the post-ore magmatic-hydrothermal fluids did not contribute to the enrichment of gold in the Lianhua deposit.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"178 ","pages":"Article 106500"},"PeriodicalIF":3.2,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445347","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":"Bonanza-type epithermal Ag-Au mineralisation in Nová Baňa (Western Carpathians, Slovakia)","authors":"Jozef Vlasáč ,&nbsp;Tomáš Mikuš ,&nbsp;Juraj Majzlan ,&nbsp;Martin Števko ,&nbsp;Peter Tuček","doi":"10.1016/j.oregeorev.2025.106493","DOIUrl":"10.1016/j.oregeorev.2025.106493","url":null,"abstract":"<div><div>The Miocene bonanza-type epithermal mineralisation Šibeničný vrch is located in the western part of the historic Nová Baňa deposit on the western slope of the Štiavnica stratovolcano. In the near-surface primary samples, bonanza accumulations contain up to 1700 ppm Ag and 283 ppm Au, while the Cu content does not exceed 59 ppm. This unusual geochemical signature, where Au exceeds Cu, Pb, or Zn, led to formation of unique mineral association in the studied samples. In this work, we focus on this mineral assemblage and its formation. The bonanza ores are banded, with rhythmically alternating chalcedony, quartz with enclosed adularia, and irregular accumulations of precious-metal minerals. The mineral assemblage hosted in the near-surface samples comprises pyrite, rozhdestvenskayaite-(Zn), zvěstovite-(Zn), zvěstovite-(Fe), argentopolybasite, argentopearceite, auropolybasite, auropearceite, Au-Ag alloys, stephanite, selenostephanite, pyrargyrite, proustite, naumannite, uytenbogaardtite, iodargyrite, and bromargyrite. These minerals document high concentration of Au, Ag, Sb, As, Se, and S in the fluid, simultaneously with lack of Cu, Pb, and Zn. Some of these sulfides incorporated Au in their structure, even though under usual geochemical conditions, they would not do so. The deeper parts of the same vein (163–166 m below the current surface) are characterised by lower Au and Ag contents (&lt;84 ppm Ag, &lt;6.95 ppm Au) and the mineral assemblage of chalcopyrite, galena, sphalerite, Au-Ag alloys, polybasite, and pearceite. Ore-bearing colloform bands of chalcedony consist of various textures, predominantly mosaic, acicular/pseudoacicular, flamboyant, or moss textures. We assume that the genesis of these chalcedony forms is related to the fluid boiling. Crustiform quartz in the deeper parts of the vein is most likely related to fluid mixing. Two possible metal transport mechanisms were cooperating in the ore-forming processes, either in bisulfide complexes or in the form of colloids (nanoparticles). Precious-metal enrichment and gangue in studied bonanza-type mineralisation links to the combination of vigorous boiling of the fluid and fluid mixing with meteoric water in the sub-surface environment. Hydrothermal breccias range from small enclaves within veinlets in the deeper parts of the studied mineralisation, but extend vertically to form pipelike body in the uppermost parts. The widespread hydrothermal breccias show that boiling was more intensive in the near-surface zone. In contrast, fluid mixing likely triggered metal precipitation in the deeper parts of the deposit.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"178 ","pages":"Article 106493"},"PeriodicalIF":3.2,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445350","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 and geochemical studies of the Xiamaidi mafic–ultramafic intrusion in the Baoshan block, with implications for Ni exploration","authors":"Jinyu Liu ,&nbsp;Shengchao Xue ,&nbsp;Yuguang Zhang ,&nbsp;Qingfei Wang ,&nbsp;Luyang Wang ,&nbsp;Chusi Li ,&nbsp;Jun Deng","doi":"10.1016/j.oregeorev.2025.106490","DOIUrl":"10.1016/j.oregeorev.2025.106490","url":null,"abstract":"<div><div>Many major magmatic Ni-Cu-Co sulfide deposits worldwide occur in the magma plumbing systems of continental flood basalt. The Xiamaidi mafic–ultramafic intrusion (∼291 Ma) is associated with the Baoshan Late Paleozoic continental flood basalts in southwestern China and hosts important information about the role of magma differentiation in sulfide mineralization in the magma plumbing systems. We address this question by comparing the petrological and geochemical features between the Xiamaidi intrusion and the Daxueshan magmatic Ni-Cu-Co sulfide deposit. The Daxueshan deposit is hosted by a mafic–ultramafic intrusion (∼301 Ma) that is also associated with the Baoshan basalts. The olivine Fo contents of in both intrusions overlap (72–83 mol%), but the Xiamaidi intrusion tends to have slightly lower olivine Fo contents. The olivine of the Xiamaidi intrusive rocks is relatively depleted in Ni (∼600–1300 ppm) and shows no correlation with Fo contents, indicating that multiple pulses of parental magma were involved in the formation of this intrusion. The contents of platinum group elements (PGE) in the Xiamaidi intrusive rocks are about one order of magnitude lower than in the reported Baoshan basalts. The Cu/Pd ratios of the Xiamaidi intrusive rocks and the Daxueshan deposit are similar and are all significantly higher than the ratios of the Baoshan basalts (0.77 × 10⁴ to 4.0 × 10⁴), indicating that the parental magmas for both intrusions had experienced early sulfide segregation at greater depths. Compared to the Baoshan basalts, the Xiamaidi and Daxueshan intrusive rocks have larger negative Nb-Ta anomalies, lower ε_Nd(t) values (–5.7 to –7.9) and higher (⁸⁷Sr/⁸⁶Sr)_i ratios (0.7111 to 0.7135) than the average compositions of the basalts [ε_Nd(t) = –1.9; (⁸⁷Sr/⁸⁶Sr)_i = 0.7073]. The differences can be explained by different mantle sources plus variable crustal contamination, with the parental magmas for the intrusive rocks derived predominantly from a subcontinental lithospheric mantle whereas the flood basalts derived mainly from the underlying mantle plume. The estimated amounts of crustal contamination in the parental magmas for the Xiamaidi and Daxueshan intrusions vary from 15 to 30 wt%. The whole-rock Sr-Nd isotopic and trace elemental data support the view that sulfide saturation in the parental magmas was mainly induced by crustal contamination. The most important implications for Ni exploration from this study are (1) at an intrusion scale, future exploration should focus on the feeders of the Xiamaidi and Daxueshan intrusive systems, and (2) at a regional scale, the ultramafic intrusions containing olivine with higher Fo contents than that in the Xiamaidi ultramafic rocks are the most favorable exploration targets in the Baoshan block.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"178 ","pages":"Article 106490"},"PeriodicalIF":3.2,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445346","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":"Metallogeny of the Jinming gold deposit in northeast Hunan, Jiangnan Orogen: Constraints from in situ sericite Rb-Sr dating, pyrite trace elements and S isotope geochemistry","authors":"Zhaohua Chen ,&nbsp;Yongjun Shao ,&nbsp;Qingquan Liu ,&nbsp;Xiong Zhang ,&nbsp;Yuce Zhang ,&nbsp;Hongtao Zhao ,&nbsp;Jie Chen ,&nbsp;Lijun Hu","doi":"10.1016/j.oregeorev.2025.106499","DOIUrl":"10.1016/j.oregeorev.2025.106499","url":null,"abstract":"<div><div>The newly discovered Jinming gold deposit in northeastern Hunan province (Eastern China) is tectonically located in the Jiangnan Orogen. The fault-controlled auriferous quartz ore veins are primarily developed in the low-grade metamorphosed Neoproterozoic Lengjiaxi Group. The alteration/mineralization comprises stage I quartz-pyrite mineralization, stage II quartz-native gold-polymetallic sulfide mineralization, and stage Ⅲ quartz-carbonate veining. Our in situ sericite Rb-Sr dating on stage II ore yielded an Early Devonian age of 412.4 ± 8.4 Ma (MSWD = 1.1). Five types of pyrite were identified, i.e., Py1 (Py1a and Py1b) in stage Ⅰ, and Py2 (Py2a, Py2b, and Py2c) in stage Ⅱ. Py1 has relatively low trace element contents and narrow δ³⁴S range (Py1a: −5.53 to −4.82 ‰, Py1b: −5.29 to −4.72 ‰), whereas Py2 is Au-As-Co-Ni rich with a broader δ³⁴S range (Py2a: −6.00 to −4.94 ‰, Py2b: −13.80 to −7.99 ‰, Py2c: –23.45 to −18.70 ‰). The distinct trace element and sulfur isotope features in Py1 and Py2 imply major physicochemical changes in the ore-forming fluids from stage I to II. At Jinming, gold occurs as native gold and refractory gold (Au⁺) in pyrite and arsenopyrite from stage II, and the invisible gold is primarily found as solid solution gold (Au⁺) within the lattice structure of pyrite. A marked positive correlation between the concentrations of Au and arsenic (As) in pyrite suggests a strong relationship between Au enrichment and As content. The pyrite’s element and sulfur isotope features imply a deep metamorphosed strata source for the ore material at Jinming. Geological and geochemical evidence suggests that the Jinming gold deposit is best classified as an orogenic type, associated with the Caledonian intracontinental orogeny.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"178 ","pages":"Article 106499"},"PeriodicalIF":3.2,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445349","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":"Mineral prospectivity mapping of orogenic gold mineralization in the Malartic-Val-d’Or Transect area, Metal Earth project, Canada","authors":"Ahmad Reza Mokhtari,&nbsp;Pouran Behnia,&nbsp;Bruno Lafrance,&nbsp;Mostafa Naghizadeh,&nbsp;Jack M. Simmons,&nbsp;Jeff R. Harris","doi":"10.1016/j.oregeorev.2025.106498","DOIUrl":"10.1016/j.oregeorev.2025.106498","url":null,"abstract":"<div><div>Mineral Prospectivity Mapping has been applied to define exploration targets for orogenic gold mineralization in the world-class Malartic-Val-d’Or area (Quebec) of the Abitibi greenstone belt, a region that contributes significantly to Canada’s annual gold production. This research utilizes lithological, geophysical, and structural data from the Malartic transect, collected as part of the Metal Earth project, to investigate factors controlling gold distribution in the region. Stepwise logistic regression and random forest algorithms were employed to map mineral prospectivity for gold potential. The overall accuracy indicates that the random forest method has outperformed logistic regression, although the latter produced an acceptable model. This conclusion is supported by the classification accuracy validated using an independent Au occurrence database and the performance metrics generated by the random forest and logistic regression models. Crustal density, shear zones, and faults are strong predictors for distinguishing mineralized and non-mineralized locations, as identified by both Random Forest and Logistic Regression models. In the Malartic-Val-d’Or region, subvertical conductive anomalies revealed by magnetotelluric data align closely with major shear zones and crustal-scale structures, such as the Cadillac-Larder Lake deformation zone, which hosts significant gold deposits. These anomalies suggest a paleo-hydrothermal footprint of mineralizing fluids and highlight their critical role in the formation of orogenic gold deposits, a pattern also observed in other mining camps across the Superior craton. These results and associated mineral prospectivity maps are integral for greenfields exploration in the Malartic region and may offer valuable insights for mineral exploration in other greenstone belts of the Superior craton.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"178 ","pages":"Article 106498"},"PeriodicalIF":3.2,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428122","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":"Assessment of pyrite and arsenopyrite compositions, in situ S isotopes, and bulk Pb isotopes from the Cape Spencer gold deposit, New Brunswick, Canada","authors":"Alan Cardenas-Vera ,&nbsp;David R. Lentz ,&nbsp;Christopher R.M. McFarlane ,&nbsp;Kathleen G. Thorne","doi":"10.1016/j.oregeorev.2025.106492","DOIUrl":"10.1016/j.oregeorev.2025.106492","url":null,"abstract":"<div><div>The Cape Spencer gold deposit is situated proximal to the boundary between two major lithotectonic zones of the Canadian Appalachians, the Caledonia and Meguma terranes, within a fold-thrust belt in southern New Brunswick along the Minas Fault Zone. Gold mineralization occurs in quartz-dominant veins with 2–5 % sulphides hosted by the highly deformed and sheared rocks of the Millican Lake Granite and the Cape Spencer Formation. In this research, <em>in situ</em> S isotope and trace-element concentrations of pyrite in combination with bulk pyrite Pb isotope analyses are presented to better understand the metal sources, fluid channels, and mechanisms of ore deposition. Based on textural characteristics and trace element concentrations, five generations of pyrite from the hydrothermal stage were identified in the ore bodies: Py1a, Py1b, Py2a, Py2b, and Py3. The first pyrite generations, Py1a and Py1b (substage I), contain higher concentrations of Co and Ni than pyrite from substages II and III and have positive δ³⁴S values ranging from +6.8 to +18.7 ‰. Economic concentrations of gold are associated with Py2a and Py2b (substage II), which occur as spongy and porous pyrite; Py2a pyrites contain visible gold along fractures and margins. Py1a to Py2b display an Au-Ag-Pb-Bi-Te association, also supported by the presence of hessite, petzite, sylvanite, and native bismuth in the gold ores. Pyrites from substage II display slightly less positive values of δ³⁴S of +1.0 to +12.3 ‰. The last identified pyrite generation, Py3 (substage III), contains no gold and is characterized by high concentrations of As and Cu compared with pyrites from the previous generations and negative δ³⁴S values of −9.8 to −3.8 ‰. This sequential shift towards more negative values from Py1 to Py2 may be induced by phase separation and wall-rock sulphidation processes, in addition to interaction with rocks of the Lancaster Formation for Py3. The generally low gold contents (&lt;0.3 ppm) in pyrite and visible gold within fractures and along pyrite grain margins suggest post-depositional dissolution of pyrite. The influx of ore fluids, consistent with cyclic decompression, induced the removal of iron from Fe-bearing minerals, mainly specular hematite that led to an increase of the Fe in the fluid, destabilizing the <span><math><msubsup><mrow><mi>A</mi><mi>u</mi><mo>(</mo><mi>H</mi><mi>S</mi><mo>)</mo></mrow><mrow><mn>2</mn></mrow><mo>-</mo></msubsup></math></span> complexes and promoted the depletion of S and subsequent gold precipitation. The ore-forming fluids were transported along major structures and derived from a mixed source that includes intrusive and metasedimentary rocks from the Avalonia and Meguma terranes, sharing similar characteristics to those values from the Meguma gold deposits, as indicated by both the S and Pb isotope signatures.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"178 ","pages":"Article 106492"},"PeriodicalIF":3.2,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422208","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":"Biogenic mineralization controls exceptional REY enrichment in Early Cambrian phosphorites from South China","authors":"Rou Peng ,&nbsp;Ruidong Yang ,&nbsp;Jiyan Chen ,&nbsp;Junbo Gao ,&nbsp;Lei Gao ,&nbsp;Chuanqian Gao","doi":"10.1016/j.oregeorev.2025.106497","DOIUrl":"10.1016/j.oregeorev.2025.106497","url":null,"abstract":"<div><div>The Early Cambrian represents a globally significant phosphorus-formation period, particularly noted for producing REY-rich phosphorites in South China. However, substantial differences exist in the REY enrichment levels among these phosphorites. Particularly, the REY contents of the Early Cambrian Meishucun Stage phosphorites from Guizhou and Yunnan exhibit pronounced disparities, with the controlling factors behind these variations remaining a subject of debate. To address this issue, this study conducted comparative analyses of representative REY-bearing phosphorites from Cambrian Meishucun Stage in Bailongtan, Yunnan province, and Zhijin, Guizhou province, China. Advanced analytic techniques, including XRF, ICP-MS, and ICP-OES, were employed to determine major, trace elements and REY concentrations in different phosphorite types. And complementary methodologies including OM, SM, SEM-EDS, and EPMA were utilized to examine the mineralogical and textural features. The results indicated that biofossils preserved in the phosphorites of both regions are small shelly fossils (SSFs), with carbonate fluorapatite as the principal component. Zhijin phosphorites exhibit significantly higher REY enrichment compared with Bailongtan phosphorites, and REY contents positively correlate with the abundance of SSFs. In-situ analyses revealed that REYs are primarily concentrated within SSFs, which were better preserved in oxic and open environments with relatively slow sedimentation rates. The multilayered nested structures of SSFs facilitate the absorption of REYs from seawater and porewater, which corresponding to the biogenic structures of bioapatite observed in modern deep-sea REY-rich sediments. These findings suggested that SSFs play a crucial role in REY enrichment, with <em>Zhijinites</em> potentially serving as the optimal host phase for REY enrichment. Conclusively, biota play an important part in the REY-rich mineralization of phosphorites, offering new insights into the genesis of global sedimentary REY-bearing phosphorites. This understanding also opens new considerations for optimizing REY extraction processes from such phosphorites.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"178 ","pages":"Article 106497"},"PeriodicalIF":3.2,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422210","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":"The role of fluid exsolution in the Li enrichment in granitic pegmatites: A case study from the Dahongliutan Li ore field in West Kunlun","authors":"Zhong-Cheng Zeng ,&nbsp;Jing-Jing Fan ,&nbsp;Zi-Long Wang ,&nbsp;Biao Du ,&nbsp;Peng Wang ,&nbsp;Zeng-Lin Hong","doi":"10.1016/j.oregeorev.2025.106491","DOIUrl":"10.1016/j.oregeorev.2025.106491","url":null,"abstract":"<div><div>Pegmatite-host Li deposits provide substantial Li resource in the globe. However, the mechanism of Li enrichment in granitic pegmatites remain enigmatic. Here, we report age and whole-rock geochemical data for the garnet-tourmaline-bearing granites (GTGs) and tourmaline-bearing granites (TGs) from the Dahongliutan rare-metal pegmatite ore field located in the Western Kunlun orogen, NW China. The formation of Li-rich pegmatites in this ore field was proposed to have an intimate temporal-spatial association to the two-mica granites (TMGs). Zircon U–Pb dating for the GTGs and TGs yielded ages of 203.2 ± 2.3 and 203.4 ± 2.7 Ma, respectively. These ages are slightly younger than those of the TMGs (ca. 220–208 Ma), but overlapping with or older than those of the Li-rich pegmatites (ca. 214–190 Ma) reported in this area. The GTGs and TGs have middle to upper crust-like Sr–Nd isotope compositions ((⁸⁷Sr/⁸⁶Sr)_i = 0.7159–0.7227; ε_Nd(<em>t</em>) =  <strong>−</strong> 10.7 to <strong>−</strong> 9.67), similar to those of the TMGs and Li-rich pegmatites. The decreasing CaO, MgO, TFe₂O₃, Sr, Ba and rare earth element contents, and increasing Na₂O, K₂O contents and Na₂O/K₂O ratios from the TMGs to GTGs, and to TGs, suggests fractionation of biotite, plagioclase and K-feldspar, monazite, muscovite, and garnet from the TMG magma. These evidence together with the field observations indicate that these granites and pegmatites in the Dahongliutan ore field represent a cogenetic evolutionary sequence. However, the contents of the incompatible element of Li decrease sharply from the TMGs to GTGs and TGs, which is likely resulted from magmatic fluid exsolution. Geochemical modeling for Li show that fluid saturation occurred at the early stage of magma evolution. In the following, the exsoluted fluids accumulation accompany by extraction of large amounts of fluid-soluble elements such as Li and Cs from the residual melts, and their removal and migration away from the granite system, may be pivotal in the generation of the Li-rich pegmatites.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"178 ","pages":"Article 106491"},"PeriodicalIF":3.2,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422416","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}