Ore Geology Reviews最新文献

{"title":"Provenance of Permian Li-rich Karst bauxite in western Guangxi, China: Evidence from geochemistry, zircon U-Pb and Hf isotopic compositions of contemporaneous-heterophase tuffaceous rocks","authors":"Jianqi Xu ,&nbsp;Baocheng Pang ,&nbsp;Guanghui Lu ,&nbsp;Chongjin Pang ,&nbsp;Jianwen Yang ,&nbsp;Dongsheng Yang ,&nbsp;Shuangqiu Yao ,&nbsp;Haipeng Xu","doi":"10.1016/j.oregeorev.2026.107134","DOIUrl":"10.1016/j.oregeorev.2026.107134","url":null,"abstract":"<div><div>Karst bauxite deposits are an important potential lithium resource, distinct from grantie-pegmatite, brine, and volcanic-sedimentary lithium. Pingguo Li-rich karst bauxite deposits in Youjiang Basin, South China represent major deposits hosted in the Heshan Formation deposited on the Late Permian carbonate platform. Contemporaneous-heterophase tuffaceous rocks of the Upper Permian Linghao Formation distribute widely surrounding the Pingguo Carbonate Platform. The tuffaceous rocks provide a definitive tracer for the provenance of Li-rich karst bauxite deposits. Integrated geochemical, zircon U-Pb chronology, and in situ Hf isotopic analyses reveal that both tuffaceous rocks and Pingguo Li-rich karst bauxite deposits formed synchronously at ∼ 259 Ma from the same source. The correlations of Zr-Hf, Nb-Ta, and Th/Sc-Zr/Sc confirm the genetic relation between tuffaceous rocks and Li-rich karst bauxite. Zircon trace elements fingerprint arc-related signature of the parent source. Critically, the Hf isotope compositions of the tuff (ε_Hf(t)≈-4.0, T_DM2≈1.5 Ga) indicate unequivocally with the Paleo-Tethyan magmatic arc, demonstrating that volcanic ash derived from Paleo Tethys. The provenance of Li-rich karst bauxite deposits in Pingguo Carbonate Platform was volcanic ash from Paleo-Tethyan arc. The volcanic ash covered the carbonate platform during the latest Middle Permian and early Late Permian and resulted in the formation of Li-rich karst bauxite, revealing the Paleo-Tethyan arc as the main source for the significant deposits.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"189 ","pages":"Article 107134"},"PeriodicalIF":3.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Petrophysical properties of the Lakkeh-Siah iron oxide-apatite mineralization and host rocks","authors":"Mohsen Shirkhani ,&nbsp;Majid Ghaderi ,&nbsp;Nematollah Rashidnejad-Omran","doi":"10.1016/j.oregeorev.2026.107146","DOIUrl":"10.1016/j.oregeorev.2026.107146","url":null,"abstract":"<div><div>This study investigates the relationship between physical properties, metasomatism, and iron oxide-apatite (IOA) mineralization in the Lakkeh-Siah deposit, located in the Central Iran structural zone. The research integrates petrophysical, geochemical, and geophysical analyses to characterize rock units, assess mineralization controls, and develop an exploration model. The mineralized and metasomatized rocks exhibit higher density (avg. 3458 kg/m³) and magnetic susceptibility (up to 12,000 × 10⁻⁶ SI) than barren sedimentary and volcanic rocks. Calcic metasomatism (actinolite, tremolite, magnetite) enhances magnetic susceptibility, while argillic/sericitic alteration reduces it. Bivariate plots (density vs. susceptibility, Q-ratio) effectively discriminate lithologies and mineralization zones. Borehole logging confirms that high-grade iron zones correlate with elevated magnetic susceptibility and conductivity, influenced by sulfide presence. The study establishes a petrophysical database for exploration, demonstrating that integrated physical property analysis improves targeting accuracy in IOA deposits.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"189 ","pages":"Article 107146"},"PeriodicalIF":3.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Iron oxide copper–gold (IOCG) deposits – A review (part 2): fluid, metal and sulfur sources and ore genesis","authors":"Roger G. Skirrow","doi":"10.1016/j.oregeorev.2026.107120","DOIUrl":"10.1016/j.oregeorev.2026.107120","url":null,"abstract":"<div><div>Genetic models for the formation of iron oxide copper–gold (IOCG) deposits have been debated since recognition of the class, with proposed ore fluid origins ranging from non-magmatic basinal to magmatic-hydrothermal, with or without fluid mixing. This review reassesses previous models by synthesising and re-interpreting fluid geochemical and stable and radiogenic isotope data for IOCG deposits worldwide. These data are integrated with previously compiled information for 10 IOCG provinces to build a new and holistic model of IOCG deposit genesis.</div><div>Although many gaps in data remain, previous disparate models can be reconciled and key features of most major IOCG deposits explained by mixing of fluids sourced from both (meta)sedimentary ± (meta)volcanic basins and from magmas. The roles of these fluids as carriers of Cu-Au differ, however, between IOCG deposits in Precambrian orogenic to post-orogenic versus Mesozoic magmatic arc settings. Relatively limited fluid geochemical and isotope data for Mesozoic arc-hosted IOCG deposits are consistent with formation of most ores from Cu-Au-bearing magmatic-hydrothermal fluids that mixed with Na-Ca-rich oxidised basin-derived brines.</div><div>In contrast, and based on variably comprehensive datasets, the Cu-Au ore fluids forming most IOCG deposits in Precambrian orogenic and post-orogenic settings are interpreted to have been Ca-Fe-Ba-rich evolved basin-derived brines ± metamorphic fluids that leached metals from Na-Ca-altered and mafic rock sequences. These generally low-sulfur fluids mixed with a second fluid, commonly of magmatic-hydrothermal origin, that carried sulfur and other volatiles (CO₂ ± P ± B ± F) as well as Fe and K ± Mo, to form most major IOCG deposits.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"189 ","pages":"Article 107120"},"PeriodicalIF":3.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanism of hydrothermal illite clay mineralization in the southern Ordos Basin, central China","authors":"Qingyang Bao ,&nbsp;Hongfei Cheng ,&nbsp;Yang Wang ,&nbsp;Shaoxian Liang","doi":"10.1016/j.oregeorev.2026.107129","DOIUrl":"10.1016/j.oregeorev.2026.107129","url":null,"abstract":"<div><div>Significant illite clay deposits, which are of considerable economic interest and genetic importance, are found in Chunhua area along the southern margin of the Ordos Basin. This study takes the Yanjiagou deposit as a representative case and integrates geological survey, mineralogy, X-ray diffraction (XRD) , scanning electron microscopy, geochemistry, K-Ar isotopic dating, and illite crystallinity analysis to systematically investigate its geological characteristics, age of mineralization, and genesis. The results indicate that the mineralized clay layers are predominantly hosted in the lower segment of the Upper Carboniferous Taiyuan Formation. The protolith is identified as a kaolinite claystone that formed through chemical precipitation, which was subsequently altered to illite through hydrothermal processes. K-Ar dating of illite yields an age of 146.8 ± 2.5 Ma, and crystallinity-based geothermometry indicates a formation temperature of approximately 210 °C, constraining the mineralization to a medium–low temperature hydrothermal event during the Late Jurassic to Early Cretaceous. A genetic model of “hydrothermal diagenetic mineralization” is proposed, wherein potassium-rich fluids migrated along structural pathways and triggered selective illitization of kaolinite precursor, resulting in zoned illite horizons. These findings not only provide key insights into Late Mesozoic hydrothermal mineralization on the southwestern margin of the North China Craton, but also offer practical guidelines for the exploration of clay mineral deposits in similar geological settings.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"189 ","pages":"Article 107129"},"PeriodicalIF":3.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fingerprinting W-Sn mineralization processes in the East Greenland Caledonides using scheelite and cassiterite U-Pb dating and trace element composition","authors":"Nynke Keulen,&nbsp;Benjamin Heredia,&nbsp;Diogo R.N. Rosa,&nbsp;Sebastian N. Malkki,&nbsp;Tonny B. Thomsen,&nbsp;David Whitehead","doi":"10.1016/j.oregeorev.2025.107049","DOIUrl":"10.1016/j.oregeorev.2025.107049","url":null,"abstract":"<div><div>Efficient mineral exploration requires early tailoring to target deposit types. Mineral assemblages of 12 different W-Sn occurrences in the East-Greenland Caledonides with scheelite and cassiterite were investigated with automated quantitative mineralogy on SEM and for their trace elements with LA-ICPMS and integrated observations were correlated through statistical analyses on literature data. Results indicate that scheelite and cassiterite trace element geochemistry can differentiate between skarn, greisen, and quartz-scheelite vein deposit types. The mineralization processes are influenced enough by specific geological settings and fluid compositions to allow for the differentiation of deposit types from mineral trace element geochemistry. These data assist in understanding complex geological histories and varied mineralization processes in the East-Greenland Caledonides. U-Pb dating of scheelite, apatite and cassiterite of samples from multiple locations reveal three distinct mineralization pulses around 425 Ma, 400 Ma, and 370 Ma, the first two linked to magmatic fluids and finally a third metamorphic fluid phase. Analyses also suggest that the scheelite closure temperature lies in the same range as the one for apatite. This approach supports more efficient and effective exploration strategies by improving the understanding of the timing and nature of mineralization events in the East-Greenland Caledonides.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"189 ","pages":"Article 107049"},"PeriodicalIF":3.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145950228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Zircon geochronology, geochemistry, and Hf isotopes of granites in the Yazigou skarn Cu–Pb–Zn deposit: Insights into Triassic skarn mineralization potential in the Qimantagh area, Qinghai Province, NW China","authors":"Jiale Wang ,&nbsp;Xiang Sun ,&nbsp;Changhai Luo ,&nbsp;Yong Fu ,&nbsp;Weiming Ma ,&nbsp;Tong Pei ,&nbsp;Ke Xiao","doi":"10.1016/j.oregeorev.2026.107136","DOIUrl":"10.1016/j.oregeorev.2026.107136","url":null,"abstract":"<div><div>The Triassic period has been suggested to be the main metallogenic epoch in the Qimantagh area of Qinghai Province. However, the porphyry copper mineralization potential of this region remains poorly constrained. Here we present zircon U–Pb ages, trace-element data, and Hf isotopic compositions from granites in the Yazigou skarn Cu–Pb–Zn deposit. The zircon U–Pb age of the mineralization-related K-feldspar granitic porphyry at Yazigou is 230 ± 2 Ma, whereas the granodiorite yields an age of 416.7 ± 4.2 Ma. The K-feldspar granitic porphyry exhibits ε_Hf(t) values of -0.4 to +4.0 and two-stage Hf model ages (T_DM2) of 1.0–1.3 Ga, suggesting derivation from melting of Mesoproterozoic to crust, accompanied by minor contributions from mantle material. Zircon trace element signatures further indicate highly magmatic oxygen fugacity (ΔFMQ = +1.0 to +2.3), consistent with typical of oxidized skarn systems. The extremely low Eu anomalies (0.01–0.03) suggest that the magma system underwent intense plagioclase fractional crystallization, implying a low water content. Although the Yazigou deposit shares a similar magma source with other metallic deposits in the Qimantagh region, comparison with the Eu anomalies of Tibet porphyry Cu deposits suggests that the low water content resulted in its limited mineralization potential.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"189 ","pages":"Article 107136"},"PeriodicalIF":3.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of the trapping temperatures and pressures of high-internal pressure CO2-bearing boiling fluid inclusion assemblages in the carbonatite-related REE deposit at Weishan, Shandong Province, China","authors":"Shenghu Li ,&nbsp;Yuxin Xiong ,&nbsp;Dapeng Li ,&nbsp;Xuefeng Yu ,&nbsp;Taitao Liang ,&nbsp;Rongjun Li ,&nbsp;Zhiming Wang ,&nbsp;Xiangxian Ma ,&nbsp;Zengsheng Li ,&nbsp;Naijie Chi ,&nbsp;Yingyu Xue ,&nbsp;Guodong Chen ,&nbsp;Chuanyuan Zhuo ,&nbsp;Ge Hu","doi":"10.1016/j.oregeorev.2026.107151","DOIUrl":"10.1016/j.oregeorev.2026.107151","url":null,"abstract":"<div><div>Carbonatite-related rare earth element (REE) deposits are the world’s primary source of light REEs. The Weishan deposit in Shandong Province, China—ranked third in the country in rare earth oxide reserves—exemplifies such mineralization. Petrographic studies reveal abundant CO₂-bearing fluid inclusions in its high-grade ore bodies. Due to their high-internal pressure, these inclusions frequently decrepitate or leak when heated on conventional heating-freezing stages (e.g., the Linkam THMSG600) at atmospheric pressure, preventing the acquisition of total homogenization temperature (<em>T</em>_h,tot) data. This limitation has hindered understanding of the evolutionary process and thermodynamic properties of the ore-forming fluids. To address this, we employed a hydrothermal diamond anvil cell (HDAC) to perform high pressure microthermometry on CO₂-bearing boiling fluid inclusion assemblages (FIAs) from the Weishan deposit. By maintaining external pressure on the high-internal pressure fluid inclusions throughout heating, we successfully obtained the <em>T</em>_h,tots and introduced a newly established two fitted lines intersection method to correct the <em>T</em>_h,tots measured with the HDAC, minimizing the influence of external pressures on the measured <em>T</em>_h,tots. As a result, the trapping temperatures and pressures of the CO₂-bearing boiling FIAs in the Weishan deposit were determined to be 682–692 °C and 646–734 MPa, respectively. These results define the temperature and pressure conditions under which depressurization immiscibility and fluid exsolution occurred within the magmatic system, and confirmed the existence of CO₂-bearing supercritical fluids in the deposit. In the future, the experimental method established herein is well-suited for thermodynamic measurements of CO₂-bearing boiling FIAs in carbonatite-related REE deposits, which often contain high-internal pressure fluid inclusions with complex multicomponent system such as H₂O-Na₂SO₄-Na₂CO₃–CO₂.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"189 ","pages":"Article 107151"},"PeriodicalIF":3.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sm-Nd geochronology of the Hoxbulak Zn-Pb deposit in Xinjiang (NW China) and its link to Paleogene Mississippi Valley-type mineralization in the Tethyan domain","authors":"Ying Wang ,&nbsp;Zhaochong Zhang ,&nbsp;Shu Zhang ,&nbsp;Zhiguo Cheng ,&nbsp;He Huang","doi":"10.1016/j.oregeorev.2025.107092","DOIUrl":"10.1016/j.oregeorev.2025.107092","url":null,"abstract":"<div><div>Sediment-hosted Zn-Pb deposits are the most important global source of Pb and Zn, yet their genesis and timing remain central questions in economic geology. Direct geochronological constraints are often difficult to obtain due to the general absence of suitable datable minerals, hindering the understanding of ore-forming processes and regional metallogenic models. The Hoxbulak Zn-Pb deposit in Xinjiang, a typical sediment-hosted Zn-Pb deposit in the southwestern Tianshan Mountains of the Central Asian metallogenic domain, has long been controversial with respect to its genetic type and mineralization age, primarily focusing on whether it is related to adjacent Permian magmatism and whether it formed syngenetically or epigenetically. In this study, we conducted precise Sm-Nd isochron dating of sphalerite, galena, and associated calcite/dolomite from the main mineralization stage, yielding a mineralization age of 55 ± 2 Ma. This result indicates that the deposit formed during the Paleogene and shows no genetic relationship with the neighboring Permian Hoxbulak pluton (261.5 ± 2.7 Ma; 273.6 ± 2.0 Ma and 274.8 ± 1.5 Ma), supporting its classification as an epigenetic Mississippi Valley-type (MVT) deposit. Integrated regional structural analysis suggests that this mineralization event was likely controlled by transpression tectonics triggered during the initial India-Eurasia collision (∼60–50 Ma). Our findings demonstrate that the Hoxbulak deposit represents a critical northwestern extension of the Tethyan MVT metallogenic belt (spanning Yunnan-Tibet-Xinjiang) and serves as its easternmost component within the Central Asian metallogenic domain—linking the classic Tethyan MVT system with the interior of the Central Asian Orogenic Belt. This study provides important constraints for exploring Paleogene MVT-type Zn-Pb deposits in Late Paleozoic carbonate formations of the South Tianshan, offering significant insights into the metallogenic patterns of Zn-Pb deposits in the junction zone between the Tethyan and Central Asian orogenic belts.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"189 ","pages":"Article 107092"},"PeriodicalIF":3.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ore genesis of the Kuhsiah-e-Urmak base-metal epithermal deposit, Iran","authors":"Amirabbas Karbalaeiramezanali ,&nbsp;Faranak Feizi ,&nbsp;Alireza Jafari Rad ,&nbsp;Mohammad Lotfi ,&nbsp;David R. Lentz","doi":"10.1016/j.oregeorev.2026.107142","DOIUrl":"10.1016/j.oregeorev.2026.107142","url":null,"abstract":"<div><div>This study investigates the mineralization characteristics and ore genesis of the Kuhsiah-e-Urmak area in the central Urumieh-Dokhtar Magmatic Belt, Iran, through fluid inclusion and isotope analyses. The intrusive units in the region, which are hosted within a marginally older volcanic series, reflect a transitional geodynamic environment, with the Kuh-Ghadeh diorite (∼18 Ma) showing arc-related features and the Marfioun tonalite (∼18 Ma) displaying a mix of arc and slab break-off characteristics, indicating an evolution from arc-related to post-arc slab failure regimes. Mineralization at the Kuhsiah-e-Urmak deposit occurs in two stages: Stage 1 (hypogene), marked by chalcopyrite-pyrite-bornite-sphalerite-galena-tetrahedrite with quartz-calcite, and Stage 2 (hypogene to supergene), characterized by chalcocite-digenite-covellite-goethite-maghemite-malachite with hematite-limonite ± jarosite ± illite. Fluid inclusion studies reveal low- to intermediate-temperature (191–230°C) and low- to medium-salinity (4–8.5 wt%) Stage 1 fluids. Stable isotope results indicate that the strongly negative δ³⁴S values of sulfides and the significantly higher δ³⁴S values of barite reflect reduction of seawater- or evaporite-derived sulfate, rather than sulfur input from magmatic volatiles. The magnitude of sulfur isotope fractionation is inconsistent with thermochemical sulfate reduction and instead supports microbial sulfate reduction and/or multistage sulfur cycling as the dominant sulfur-generating processes<strong>.</strong> The δ¹⁸O and δ¹³C values further record extensive fluid–rock interaction with meteoric waters and limestones in the region. Fluid inclusion salinity–temperature trends exhibit a positive correlation, consistent with dilution of hydrothermal fluids by infiltrating meteoric water. Stage 1 mineralization was driven by high-temperature magmatic hydrothermal fluids, while Stage 2 resulted from progressive mixing with cooler meteoric waters at shallow crustal levels to supergene weathering. These findings classify the Kuhsiah-e-Urmak deposit as a low-sulfidation epithermal Cu (Ag–Pb–Zn) deposit, and highlight the dominant role of seawater- or evaporite-derived oxidized sulfur and meteoric water mixing in the evolution of its hydrothermal system.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"189 ","pages":"Article 107142"},"PeriodicalIF":3.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In situ U–Pb geochronology and geochemistry of garnets in the Hongniu Cu-polymetallic distal skarn deposit, SW China: Implication for ore-forming process","authors":"Xiao–yi Wang ,&nbsp;Jing Zhang ,&nbsp;Xiao-long Bian ,&nbsp;Zi-da Tong","doi":"10.1016/j.oregeorev.2026.107137","DOIUrl":"10.1016/j.oregeorev.2026.107137","url":null,"abstract":"<div><div>The Hongniu deposit is a typical distal skarn-type Cu-polymetallic deposit situated in the central Geza arc of the Sanjiang Tethyan region. This area records multiple magmatic events, represented by partially overlapping NNW-trending Late Indosinian and approximately NS-trending Late Yanshanian magmatic rock belts. Although both intrusive suites occur in the Hongniu district, the skarn shows no direct contact with them. Consequently, the genesis and geochronology of the deposit remain controversial, primarily due to the absence of spatiotemporally related intrusions. In this study, we performed in situ U–Pb dating and major and trace element analyses on garnets from Hongniu using LA-ICP-MS and EMPA. The garnets in the skarn were divided into two generations (Grt I and Grt II). Grt I is grossular-rich (Gro_59.71And_37.71 to Gro₈₂And₁₄) and exhibits LREE-enrichment with a pronounced positive Eu anomaly. In contrast, Grt II belongs to the grossular-andradite solid solution series (Gro_11.87-69.27 and And_29.49-86.93) and is characterized by HREE-enrichment with a negative Eu anomaly. The lower intercept U–Pb age of Grt I is 82.53 ± 1.10 Ma (MSWD = 1.3, n = 56), constraining the skarn formation to the Late Yanshanian period, consistent with the emplacement age of the local quartz monzonite porphyry. Geochemical data suggest that REE³⁺ incorporation into garnet is governed mainly by a Mg²⁺–REE³⁺ coupled substitution mechanism, with a minor contribution from an Al³⁺–REE³⁺ (YAG-type) substitution. From early to late stages, decreasing U concentrations reflect a continuous increase in oxygen fugacity of the ore-forming system, while declining ΣREE and δEu values indicate a gradual rise in the pH of the ore-forming fluids. Concurrently, the dominant fluid–rock interaction mechanism shifted from diffusion to infiltration metasomatism. This study establishes a clear temporal link between the Hongniu deposit and Yanshanian magmatism, confirming that mineralization is unrelated to Indosinian diorite porphyrite emplacement.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"189 ","pages":"Article 107137"},"PeriodicalIF":3.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}