Acta Geologica Sinica ‐ English Edition最新文献

Allanite Alteration-Driven Fractionation and Enrichment of Rare-Earth Elements (REEs) in Regolith-Hosted Deposits: Example From the Tengchong Block, SW China 风化岩矿床中褐榴石蚀变驱动的稀土元素分馏与富集——以腾冲地块为例

IF 2.1 3区地球科学

Acta Geologica Sinica ‐ English Edition Pub Date : 2026-08-28 Epub Date: 2026-07-07 DOI: 10.1111/1755-6724.70082

Long Tang, Qiang Weng, Haijun Yu, Wubin Yang, Wenchang Li, Hecai Niu, Yuancan Ying, Yufeng Huang

{"title":"Allanite Alteration-Driven Fractionation and Enrichment of Rare-Earth Elements (REEs) in Regolith-Hosted Deposits: Example From the Tengchong Block, SW China","authors":"Long Tang, Qiang Weng, Haijun Yu, Wubin Yang, Wenchang Li, Hecai Niu, Yuancan Ying, Yufeng Huang","doi":"10.1111/1755-6724.70082","DOIUrl":"https://doi.org/10.1111/1755-6724.70082","url":null,"abstract":"<div>\u0000 \u0000 <p>Magmatic–hydrothermal alteration of rare-earth element (REE)-rich accessory minerals in granitoids is critical for understanding light REE (LREE) and heavy REE (HREE) fractionation in regolith-hosted ion-adsorption REE (iREE) deposits. However, whether Cl<sup>−</sup>-rich and F<sup>−</sup>–<span></span><math></math>-rich fluids exert a key control on this fractionation during the magmatic–hydrothermal stage remains poorly constrained in the Tengchong Block of western Yunnan, China. This study integrates petrography, Raman spectroscopy and in situ elemental/isotopic (U‒Pb, Nd) analyses to compare allanite from altered bedrocks of the newly discovered Jueyeba (LREE-dominated) and Tuguanzhai (HREE-dominated) iREE deposits in Tengchong. The results show that magmatic (Aln-1) and altered (Aln-2/3) allanites share the same U‒Pb age (42.8 ± 0.9 Ma) and have similar <i>ε</i><sub>Nd</sub>(<i>t</i>) values but different ranges (Jueyeba −10.7 to −7.5; Tuguanzhai −6.9 to −5.4), implying different alteration fluids between the two localities within a relatively closed magmatic–hydrothermal autometasomatic system. At Jueyeba, altered allanite shows F and Th depletion but U enrichment, indicating relatively Cl<sup>−</sup>-rich, acidic, and higher-temperature fluids that mobilise LREEs. At Tuguanzhai, higher F and Th contents with biotite chloritisation and calcite indicate relatively F<sup>−</sup>–<span></span><math></math>-rich, alkaline, and lower-temperature fluids that efficiently mobilise HREEs. Thus, allanite fingerprint fluid properties affect LREE/HREE fractionation and iREE deposit type.</p>\u0000 </div>","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"100 4","pages":"1187-1203"},"PeriodicalIF":2.1,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148823196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Provenance of the Red Sea Beach Sediments: Constraints From Zircon U-Pb Geochronology and Sediment Geochemistry 红海海滩沉积物的物源：来自锆石U-Pb年代学和沉积物地球化学的约束

IF 2.1 3区地球科学

Acta Geologica Sinica ‐ English Edition Pub Date : 2026-08-28 Epub Date: 2026-06-09 DOI: 10.1111/1755-6724.70076

Mustafa Salieh, Xinong Xie, John S. Armstrong-Altrin, Dafalla Wadi

{"title":"Provenance of the Red Sea Beach Sediments: Constraints From Zircon U-Pb Geochronology and Sediment Geochemistry","authors":"Mustafa Salieh, Xinong Xie, John S. Armstrong-Altrin, Dafalla Wadi","doi":"10.1111/1755-6724.70076","DOIUrl":"https://doi.org/10.1111/1755-6724.70076","url":null,"abstract":"<div>\u0000 \u0000 <p>Young continental rift settings are premier sites for studying the dynamic interplay between sediment provenance and depositional setting. We integrated geochemical and detrital zircon U–Pb geochronology data of the Red Sea beach sediments to infer the weathering history and identify source terranes. Chemical composition with low Al<sub>2</sub>O<sub>3</sub>/TiO<sub>2</sub> ratios suggests an apparent mafic-to-intermediate provenance. Although internal variability exists, the chemical index of weathering (CIW) and Th, Sr, U and Ba contents reveal moderate weathering intensity in the source region. This interpretation is contradicted by our zircon U–Pb data, which uniformly fingerprint the felsic-to-intermediate Neoproterozoic (550–990 Ma) Arabian–Nubian Shield (ANS) as the single primary source. We resolve this paradox by demonstrating that robust coastal processes fundamentally overprint the primary source signature. Intense hydrodynamic sorting in heavy mineral placers removes light, felsic minerals, creating a residual deposit with an artificial ‘mafic’ signature and an artificially high CIW signal. Elsewhere, the detrital signal is masked by biogenic carbonate dilution. Furthermore, a subordinate suite of recycled Archean to Cretaceous zircons reveals cryptic contributions from the regional Nubian Sandstone Formation, tracking long-term crustal inheritance. This work provides a case study of how depositional processes can mimic and mask source signatures in an active rift margin.</p>\u0000 </div>","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"100 4","pages":"1169-1186"},"PeriodicalIF":2.1,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148823302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Crust–Mantle Architecture Remodelled by Mantle Plumes: Evidence From Late Permian (ca. 260 Ma) Gabbro–Monzonite Association in the Inner Zone of the Emeishan Large Igneous Province 地幔柱重塑的壳幔结构：峨眉山大火成岩省内带晚二叠世（约260 Ma）辉长岩-二长岩组合证据

IF 2.1 3区地球科学

Acta Geologica Sinica ‐ English Edition Pub Date : 2026-08-28 Epub Date: 2026-06-09 DOI: 10.1111/1755-6724.70079

Yihang Ma, Jiangfeng Qin, Shaocong Lai, Xiaoping Long, Yunpeng Yang, Renzhi Zhu

{"title":"Crust–Mantle Architecture Remodelled by Mantle Plumes: Evidence From Late Permian (ca. 260 Ma) Gabbro–Monzonite Association in the Inner Zone of the Emeishan Large Igneous Province","authors":"Yihang Ma, Jiangfeng Qin, Shaocong Lai, Xiaoping Long, Yunpeng Yang, Renzhi Zhu","doi":"10.1111/1755-6724.70079","DOIUrl":"https://doi.org/10.1111/1755-6724.70079","url":null,"abstract":"<div>\u0000 \u0000 <p>Crust–mantle architecture in large igneous provinces (LIPs) controls magma generation and crustal growth. The coeval gabbro and monzonite in the inner zone of the Emeishan Large Igneous Province (ELIP) provide a key opportunity. They display different whole-rock and mineral compositions, indicating different sources and melting conditions. The gabbro displays moderate TiO<sub>2</sub> and MgO contents, with Ti/Y ratios of 408–413. Its elevated Nb/Ta and Zr/Hf ratios, evolved zircon Hf isotope, and apatite chemistry suggest a volatile-poor primitive melt, which was derived from the melting of sub-continental lithospheric mantle. The monzonite displays high Zr and Nb contents, TFeO/MgO and 10,000 × Ga/Al ratios, indicating high-temperature melting of mafic lower crust, the high Sr contents suggest plagioclase incorporation into the melts. Its relatively depleted isotopic compositions (<i>ε</i><sub>Nd</sub>(<i>t</i>) = +3.2 to +3.7; <i>ε</i><sub>Hf</sub>(<i>t</i>) = +0.87 to +0.88) reveal a juvenile crust source region. Apatite in the monzonite indicates a volatile-rich melt, supporting a high-temperature crustal melting origin. This geochemical dichotomy illuminates a two-stage crustal evolution model: (1) melting of plume-modified lithospheric mantle to generate the gabbro, followed by (2) thermal remelting of the juvenile mafic crust to form the monzonite. Such plume-induced crust–mantle interaction offers a window into understanding crust–mantle architecture in global LIPs.</p>\u0000 </div>","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"100 4","pages":"1045-1062"},"PeriodicalIF":2.1,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148823299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Geochemical, Fluid Inclusions and Stable Isotopes Constraint on the Genesis of the Hendouabad Cu–Au Mineralization, Central Urumieh–Dokhtar Magmatic Arc, Iran 伊朗乌鲁木齐-多克塔尔岩浆弧中部Hendouabad铜金矿化成因的地球化学、流体包裹体和稳定同位素约束

IF 2.1 3区地球科学

Acta Geologica Sinica ‐ English Edition Pub Date : 2026-08-28 Epub Date: 2026-07-17 DOI: 10.1111/1755-6724.70075

Maryam Tarmas Hafshejani, Soroush Modabberi, Davood Raeisi, Dunya Maronsi

{"title":"Geochemical, Fluid Inclusions and Stable Isotopes Constraint on the Genesis of the Hendouabad Cu–Au Mineralization, Central Urumieh–Dokhtar Magmatic Arc, Iran","authors":"Maryam Tarmas Hafshejani, Soroush Modabberi, Davood Raeisi, Dunya Maronsi","doi":"10.1111/1755-6724.70075","DOIUrl":"https://doi.org/10.1111/1755-6724.70075","url":null,"abstract":"<div>\u0000 \u0000 <p>The Hendouabad Cu–Au deposit, located in the central Urumieh–Dokhtar Magmatic Arc, represents a newly explored example of an epithermal deposit hosted by Late Eocene volcanic rocks of basaltic andesite to andesite composition. Mineralization occurs in two zones: A Cu–Au zone in the east and a Cu-only zone in the west hosted by andesite, basalt and associated dikes. Ore minerals include pyrite, chalcopyrite, chalcocite, galena and bornite, and enargite with supergene assemblages of malachite, haematite and chrysocolla. Hydrothermal alteration is dominated by propylitic and silicic assemblages. Fluid inclusions yielded homogenization temperatures of 109–280°C and low-to-moderate salinities (1.6–9.0 wt% NaCl equiv.), with petrographic evidence of boiling. Stable isotope analyses indicate mixed magmatic–meteoric signatures, with quartz- and epidote-derived <i>δ</i><sup>18</sup>O<sub>fluid</sub> values ranging from +2.2‰ to +14.2‰ and sulphide <i>δ</i><sup>34</sup>S values from (−12.0‰ to −5.3‰, CDT). These results suggest that ore-forming fluids were derived from a magmatic source but were strongly modified by meteoric water infiltration and evolving redox conditions. The combined geological, petrographic, geochemical, fluid inclusion and isotopic evidence supports classification of the Hendouabad deposit as a structurally controlled low-to-intermediate sulphidation epithermal Cu–Au system formed through boiling, mixing and cooling of magmatic–meteoric hydrothermal fluids.</p>\u0000 </div>","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"100 4","pages":"1145-1168"},"PeriodicalIF":2.1,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148823181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Petrogenetic Controls on Ion-Adsorption Type REE Mineralisation in Western Yunnan, China: Insights From Contrasting Palaeogene Granites in the Banggunjianshan and Polunshan Plutons 滇西离子吸附型稀土矿化的成因控制——来自邦冈尖山和坡伦山岩体古近系花岗岩对比的启示

IF 2.1 3区地球科学

Acta Geologica Sinica ‐ English Edition Pub Date : 2026-08-28 Epub Date: 2026-08-05 DOI: 10.1111/1755-6724.70090

Yuancan Ying, Pengpeng Zhao, Haijun Yu, Wenchang Li, Qiang Weng, Yufeng Huang, Shaoyong Jiang

{"title":"Petrogenetic Controls on Ion-Adsorption Type REE Mineralisation in Western Yunnan, China: Insights From Contrasting Palaeogene Granites in the Banggunjianshan and Polunshan Plutons","authors":"Yuancan Ying, Pengpeng Zhao, Haijun Yu, Wenchang Li, Qiang Weng, Yufeng Huang, Shaoyong Jiang","doi":"10.1111/1755-6724.70090","DOIUrl":"https://doi.org/10.1111/1755-6724.70090","url":null,"abstract":"<div>\u0000 \u0000 <p>Ion-adsorption type rare earth element (iREE) deposits form by intense lateritic weathering of granitoids and constitute a critical global REE resource. Recently, Cenozoic granite-related iREE prospects have been identified within the Tengchong Block, Southwest China. However, the specific granitic compositions responsible for generating these deposits in the Tengchong Block remain poorly constrained, hindering effective exploration. We present petrographic, geochronological and whole-rock geochemical data for the Banggunjianshan (BGJS) and Polunshan (PLS) plutons and their associated regolith. Zircon U‒Pb dating indicates ∼50 Ma emplacement of the BGJS monzogranite, consistent with residual zircon ages from the overlying regolith-hosted deposits. They host abundant readily weatherable REE-bearing minerals (allanite and titanite) and exhibit elevated whole-rock ΣREE contents (381–906 ppm). Geochemically, this intrusion is metaluminous to slightly peraluminous and enriched in Th, U, Zr and Hf. These characteristics indicate a strongly differentiated nature with a transitional I-A affinity, conducive to REE enrichment. In contrast, the PLS granite (∼62 Ma) is characterised by lower ΣREE abundances (218–290 ppm) and sparse allanite and titanite. It is high-K calc-alkaline and depleted in HFSEs, consistent with weakly fractionated I-type granite. These results demonstrate that Eocene monzogranites constitute the primary exploration target for iREE deposits within the Tengchong Block.</p>\u0000 </div>","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"100 4","pages":"1220-1237"},"PeriodicalIF":2.1,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148823222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Hydrochemical Evolution of Produced Water in Coalbed Methane Wells: Implications for Multi-Seam Co-Production in the Hancheng Block, Ordos Basin 鄂尔多斯盆地韩城区块煤层气井采出水水化学演化及其对多煤层联产的启示

IF 2.1 3区地球科学

Acta Geologica Sinica ‐ English Edition Pub Date : 2026-08-28 Epub Date: 2026-07-29 DOI: 10.1111/1755-6724.70084

Lingling Lu, Chen Guo, Chao Deng, Ruiteng Li, Taherdangkoog Reza

{"title":"Hydrochemical Evolution of Produced Water in Coalbed Methane Wells: Implications for Multi-Seam Co-Production in the Hancheng Block, Ordos Basin","authors":"Lingling Lu, Chen Guo, Chao Deng, Ruiteng Li, Taherdangkoog Reza","doi":"10.1111/1755-6724.70084","DOIUrl":"https://doi.org/10.1111/1755-6724.70084","url":null,"abstract":"<div>\u0000 \u0000 <p>Multi-seam co-production is a key strategy for enhancing coalbed methane (CBM) recovery in multi-layered coal formations. The Hancheng block of the Ordos Basin was among the first regions to achieve commercial CBM production. However, there are technical difficulties in identifying the sources of produced fluids. Produced water holds valuable geological and drainage insights. Therefore, to evaluate the role of hydrochemistry in CBM productivity and co-production compatibility, produced water samples and surface water samples were collected from the Hancheng block. The deuterium-excess phenomenon in isotopic compositions can indicate the level of groundwater retention. Desulphurization and evaporative concentration are the primary mechanisms driving the evolution of produced water chemistry. The evolutionary trend with increasing depth shows an increase in total dissolved solids (TDS), a decrease in pH and a change in water type from Na-HCO<sub>3</sub> to Na-Cl. The positive correlation between produced water retention and gas productivity arises from the fact that the discharge of the retained water facilitates reservoir depressurization. The Taiyuan Formation coal seams exhibit excellent co-production compatibility. Stronger marine sedimentary signatures in produced water correlate with higher gas production. This study provides a basis for identifying fluid interference and optimizing production layer combinations in commingled CBM production under multi-seam conditions.</p>\u0000 </div>","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"100 4","pages":"1274-1291"},"PeriodicalIF":2.1,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148823153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mechanism and Tectonic Background of Exhumation History of Volcanic-Type Uranium Deposits in the Hongshanzi Area of the Great Xing'an Range, Inner Mongolia: Constraints From Apatite Fission Track 内蒙古大兴安岭红山子地区火山型铀矿发掘史的机制与构造背景——来自磷灰石裂变径迹的约束

IF 2.1 3区地球科学

Acta Geologica Sinica ‐ English Edition Pub Date : 2026-08-28 Epub Date: 2026-06-29 DOI: 10.1111/1755-6724.70063

Fengjun Nie, Jin Zhang, Fei Xia, Zhaobin Yan, Yannan Wang, Dongguang Yang, Jianfeng He, Shan Jiang, Changdong Wang, Zhibing Feng, Xin Zhang, Jimu Li

{"title":"Mechanism and Tectonic Background of Exhumation History of Volcanic-Type Uranium Deposits in the Hongshanzi Area of the Great Xing'an Range, Inner Mongolia: Constraints From Apatite Fission Track","authors":"Fengjun Nie, Jin Zhang, Fei Xia, Zhaobin Yan, Yannan Wang, Dongguang Yang, Jianfeng He, Shan Jiang, Changdong Wang, Zhibing Feng, Xin Zhang, Jimu Li","doi":"10.1111/1755-6724.70063","DOIUrl":"https://doi.org/10.1111/1755-6724.70063","url":null,"abstract":"<div>\u0000 \u0000 <p>The Guyuan–Hongshanzi uranium metallogenic belt (GHUMB) in North China, particularly the Hongshanzi area within the southern Great Xing'an Range (GXR), hosts uranium mineralization significantly impacted by post-mineralization uplift and exhumation. Field investigations, drill core analysis, electron probe microanalysis (EPMA) and apatite fission track (AFT) dating reveal that uranium orebodies occur within basement uplift zones hosted by the Upper Jurassic Manketou'ebo and Xinmin formations, Lower Permian Dashizhai Formation and Hercynian granodiorite. These orebodies are predominantly shallow and are structurally controlled, associated with hydrothermal alteration including carbonatization, silicification, hematitization, chloritization, fluoritization and sulfidization. Critically, deep-seated potash feldspathization and albitization features are now exposed at shallow depths or the surface. AFT analysis and thermal history modelling indicate rapid cooling during 70–50 Ma, signifying rapid uplift through the partial annealing zone to near-surface levels. This evidence, combined with the surface exposure of deep alteration, demonstrates that primary uranium mineralization initially formed at depths of ∼2–4 km during the Cretaceous. Subsequent rapid uplift triggered intense erosion, preserving some orebodies shallowly while eroding others and transporting uranium into adjacent basins, potentially contributing to secondary sandstone-type mineralization.</p>\u0000 </div>","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"100 4","pages":"1238-1262"},"PeriodicalIF":2.1,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148823154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mineral Spectral Mapping of Chlorite–Muscovite: Locating Concealed Mineralization in the Dahongshan Cu-Fe Deposit in Central Yunnan, Southwest China 绿泥石-白云母矿物光谱填图——滇中大红山铜铁矿隐伏矿化定位

IF 2.1 3区地球科学

Acta Geologica Sinica ‐ English Edition Pub Date : 2026-08-28 Epub Date: 2026-05-30 DOI: 10.1111/1755-6724.70078

Jiakun Cai, Shenjin Guan, Tao Ren, Tianci Yang, Liuqing Meng, Long Sun, Xin Jin

{"title":"Mineral Spectral Mapping of Chlorite–Muscovite: Locating Concealed Mineralization in the Dahongshan Cu-Fe Deposit in Central Yunnan, Southwest China","authors":"Jiakun Cai, Shenjin Guan, Tao Ren, Tianci Yang, Liuqing Meng, Long Sun, Xin Jin","doi":"10.1111/1755-6724.70078","DOIUrl":"https://doi.org/10.1111/1755-6724.70078","url":null,"abstract":"<div>\u0000 \u0000 <p>The Dahongshan Cu-Fe deposit is located within the central Yunnan uplift, bordered by the Honghe and Lüzhijiang faults. It exemplifies a typical stratabound-hydrothermal reworked deposit within the Kangdian Cu-Fe metallogenic belt, situated on the western margin of the Yangtze Block. This study focused on the 60 m elevation above sea level. Using short-wave infrared (SWIR) spectroscopy, we analysed the spectral parameters of alteration minerals, primarily the chlorite group and muscovite. Spatial distribution models were developed through mineral spectral mapping to quantify the relationship between alteration minerals and copper grades. Key findings include: (1) Copper grades exceed the industrial cut-off grade of 0.2 wt% in zones corresponding to moderate to high relative spectral index values of chlorite-group minerals. (2) High chlorite spectral peak intensity zones are spatially coincident with high-grade Cu mineralization, reflecting the paragenetic association of chlorite and sulphides in hydrothermal fluid pathways. (3) Muscovite crystallinity is on average lower in ore-proximal zones than in surrounding wall rock. This distinct difference reflects Cu mineralization–related hydrothermal alteration, which induces muscovite lattice distortion and consequent crystallinity reduction in ore-bearing hydrothermal fluid zones. In conclusion, the spatial distribution of chlorite content, its spectral characteristics, and the pattern of muscovite crystallinity attenuation provide essential geological-spectral criteria for predicting concealed ore bodies within the Dahongshan Cu-Fe deposit.</p>\u0000 </div>","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"100 4","pages":"1263-1273"},"PeriodicalIF":2.1,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148823216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Periodical Thickening of Continental Crust in Northern Xizang (Tibet), SW China: Insights From Late Mesozoic Magmatism in the Middle Bangong–Nujiang Suture Zone 西藏北部大陆地壳的周期性增厚——来自班公-怒江缝合带中部晚中生代岩浆活动的启示

IF 2.1 3区地球科学

Acta Geologica Sinica ‐ English Edition Pub Date : 2026-08-28 Epub Date: 2026-08-04 DOI: 10.1111/1755-6724.70093

Ming Zheng, Yang Song, Juxing Tang, Zhibo Liu, Qin Wang, Bo Liu, Faqiao Li, Yiling Hu

{"title":"Periodical Thickening of Continental Crust in Northern Xizang (Tibet), SW China: Insights From Late Mesozoic Magmatism in the Middle Bangong–Nujiang Suture Zone","authors":"Ming Zheng, Yang Song, Juxing Tang, Zhibo Liu, Qin Wang, Bo Liu, Faqiao Li, Yiling Hu","doi":"10.1111/1755-6724.70093","DOIUrl":"https://doi.org/10.1111/1755-6724.70093","url":null,"abstract":"<div>\u0000 \u0000 <p>The middle Bangong–Nujiang suture zone (MBN) has emerged as the most intensely debated area in recent studies on the tectonic dynamics and geological evolution of the Bangong–Nujiang Ocean. This study presents an integrated analysis of geochemical, geochronological and isotopic data for the Leibao intrusions in the MBN and aims to clarify its petrogenesis and tectonic settings. The Leibao intrusions (77–79 Ma) are monzodiorite to granite in composition with a wide range of SiO<sub>2</sub> (52.5–81.5 wt%) and high K<sub>2</sub>O content, affiliated with high-K calc-alkaline I-type granites. Leibao intrusions were formed by partial melting of the juvenile lower crust. They were subjected to varying degrees of middle–upper crustal contamination and fractional crystallisation during ascent and emplacement in a post-collisional extensional setting. We propose that the MBN experienced three distinct magmatic episodes during the Mesozoic: Late Jurassic (> 150 Ma), Early Cretaceous (125–105 Ma) and Late Cretaceous (< 95 Ma), with two apparent magmatic gaps of 150–125 and 105–95 Ma. Periodic fluctuations in the Sr/Y ratio, <i>ε</i><sub>Hf</sub>(<i>t</i>), and <i>T</i><sub>Zr</sub> (°C) values of the Late Mesozoic rocks indicate possible periodic thickening of the continental crust, similar to the Cordilleran orogenic systems.</p>\u0000 </div>","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"100 4","pages":"1010-1025"},"PeriodicalIF":2.1,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148823217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Rotation of the Eastern Lhasa Terrane Since the Late Cretaceous: Implications for Neo-Tethys Oblique Convergence and Distributed Deformation in Southern Tibet 晚白垩世以来拉萨地体东部的旋转：对藏南新特提斯斜辐合和分布变形的启示

IF 2.1 3区地球科学

Acta Geologica Sinica ‐ English Edition Pub Date : 2026-08-28 Epub Date: 2026-08-05 DOI: 10.1111/1755-6724.70080

Xingduo Ma, Yalin Li, Shuai Li, Zijian Li, Xiaodong Tan

{"title":"Rotation of the Eastern Lhasa Terrane Since the Late Cretaceous: Implications for Neo-Tethys Oblique Convergence and Distributed Deformation in Southern Tibet","authors":"Xingduo Ma, Yalin Li, Shuai Li, Zijian Li, Xiaodong Tan","doi":"10.1111/1755-6724.70080","DOIUrl":"https://doi.org/10.1111/1755-6724.70080","url":null,"abstract":"<div>\u0000 \u0000 <p>Dyke swarms preserve both emplacement geometry and subsequent tectonic overprints, providing valuable constraints on crustal kinematics. Here, we re-evaluate Late Cretaceous tectonic rotation in the Eastern Gangdese belt of the Lhasa terrane, southern Tibet, by applying the net tectonic rotation (NTR) method to published palaeomagnetic and structural data. The preferred solution indicates a 26.2° counterclockwise vertical-axis rotation about a pole at <i>D</i> = 133.7° and <i>I</i> = 38.1°, while restoring the dykes to near-vertical initial orientations. This estimate is slightly larger than previous tilt-corrected results, reflecting the tighter geometric constraints imposed by the NTR framework through the joint restoration of magnetization vectors and dyke orientations. We interpret the observed rotation as the cumulative result of multiple tectonic processes associated with India–Asia convergence, most plausibly including Late Cretaceous Neo-Tethyan oblique convergence and later distributed intracontinental strike-slip deformation. Our results provide a new quantitative constraint on the kinematic evolution of southern Tibet and further demonstrate the value of dyke-based NTR analysis for reconstructing tectonic deformation in structurally complex orogenic systems.</p>\u0000 </div>","PeriodicalId":7095,"journal":{"name":"Acta Geologica Sinica ‐ English Edition","volume":"100 4","pages":"965-974"},"PeriodicalIF":2.1,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148823223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0