Acta Geochimica最新文献

{"title":"Sulfur and copper isotope fractionation during planetesimal collisions: Insights from shock metamorphism in ordinary chondrites","authors":"Ming-Yang Li,&nbsp;Dan Zhu,&nbsp;De-Liang Wang,&nbsp;Shi-Jie Li,&nbsp;Xiong-Yao Li,&nbsp;Jian-Zhong Liu,&nbsp;Ying-Kui Xu","doi":"10.1007/s11631-026-00879-x","DOIUrl":"10.1007/s11631-026-00879-x","url":null,"abstract":"<div><p>The accretion of terrestrial planets involved violent collisions among planetesimals, but the mechanisms of volatile element loss during these impacts remain debated. Chondrites, the building blocks of planets, preserve a direct record of these processes. To investigate the behavior of volatiles during impacts, we conducted a paired study of sulfur (S) and copper (Cu) elemental abundances and isotope compositions in shock-melted and unmelted portions of three ordinary chondrites (Chelyabinsk LL5, Viñales L4, Tassédet 004 H5). Our results reveal that sulfur is highly mobile during shock metamorphism. Its migration mechanism transitions from sulfide melt injection at lower shock levels to sulfide decomposition and S₂ vapor transport at higher intensities. The latter process leads to substantial S loss and pronounced heavy isotope enrichment in shock melt pockets (SMPs). In contrast, copper exhibits limited volatility, resulting in negligible Cu isotope fractionation under most shock conditions. Measurable Cu loss and heavy isotope enrichment were observed only in the most intensely shocked sample. Mass balance modeling indicates that these processes occurred under extreme shock conditions, and the observed isotope fractionation is best explained by vaporization in a diffusion-limited regime. Our findings demonstrate that impact-induced vapor loss is an effective mechanism for planetary sulfur depletion, whereas the Cu inventory of planetary bodies was likely governed by sulfide segregation during magmatic differentiation rather than evaporation during accretionary collisions.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"45 4","pages":"973 - 984"},"PeriodicalIF":1.4,"publicationDate":"2026-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148782660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemistry and petrogenesis of basement grey granitoid gneisses from the Chhotanagpur Gneissic Complex, eastern India: Implications for the Mesoproterozoic continental arc magmatism","authors":"Sukhendu Ray,&nbsp;Bapi Goswami,&nbsp;Yoann Gréau,&nbsp;Chittaranjan Bhattacharyya","doi":"10.1007/s11631-026-00873-3","DOIUrl":"10.1007/s11631-026-00873-3","url":null,"abstract":"<div><p>This study investigates the basement migmatitic Grey Granitoid Gneisses (GGG) along the southern margin of the Chhotanagpur Gneissic Complex (CGC) in the Eastern Indian Shield through detailed petrography, mineral chemistry, whole-rock geochemistry, LA–ICP–MS U–Pb zircon geochronology, Hf isotopic analysis, and petrogenetic–tectonic interpretation. The GGG consists of medium-grained, granoblastic mesosomes with compositions spanning tonalite, trondhjemite, granodiorite, and granite. These rocks exhibit calc-alkaline, I-type affinities are metaluminous to weakly peraluminous, and range from magnesian to ferroan. Zircon grains are stocky to moderately elongate, mostly subrounded to rounded, and display oscillatory zoning, consistent with magmatic crystallization. Both whole-rock and zircon REE patterns show moderate fractionation with negative Eu anomalies. Primitive mantle–normalized spider diagrams reveal enrichment in Rb, K, Ba, Th, and U, and pronounced depletion in Nb, Ta, Sr, P, and Ti—signatures characteristic of arc-related granitoids. Low Nb/U (4.07–7.3) and Ce/Pb (0.52–4.1) ratios, together with high Th/U ratios (9.48–11.14), further indicate a predominantly crustal source. U–Pb zircon dating constrains GGG magmatism to 1397 ± 18 Ma (MSWD = 1.9). Zircon Lu–Hf isotopic compositions [εHf(t) = + 2.52 to − 6.86; <i>T</i>_DM2 = 1.7–2.4 Ga] suggest derivation from juvenile amphibolitic lower crust variably hybridized with older crustal components. The presence of inherited 1616 Ma zircons, along with enclaves of amphibolite and migmatite, attests to direct remelting of older crust. Petrogenetic modeling indicates that the GGG mesosomes formed through ~ 20% partial melting of high-K metabasalts (amphibolites). Collectively, these results suggest that the 1616 Ma amphibolitic crust in the study area originated within a regional Paleoproterozoic continental arc–back-arc system along the Satpura Orogenic Belt, and subsequently served as a fertile source for Mesoproterozoic hybrid magmatism.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"45 3","pages":"652 - 680"},"PeriodicalIF":1.3,"publicationDate":"2026-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148196265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Whole-rock geochemical constraints on origin of ferruginous chert and associated rocks from the Neoproterozoic Buem Structural Unit, Eastern Ghana: Implications for hydrothermal activity and tectonic setting","authors":"Rauda Adam Addae,&nbsp;Huayong Chen,&nbsp;Bing Xiao","doi":"10.1007/s11631-026-00872-4","DOIUrl":"10.1007/s11631-026-00872-4","url":null,"abstract":"<div><p>Ferruginous cherts and associated siliciclastic rocks of the Neoproterozoic Buem Structural Unit (Eastern Ghana) provide a unique archive for reconstructing fluid sources, hydrothermal processes, and basin evolution along the margin of the West African Craton. This study presents new whole-rock major and trace element geochemical data from cherts, shales, and sandstones to constrain the origin of the ferruginous facies and evaluate the influence of hydrothermal activity and depositional redox conditions. The ferruginous cherts display enrichments in Fe₂O₃, Ba, Sr, and transition metals (Cu, Ni, Zn), together with elevated ΣREE and moderately fractionated chondrite-normalized patterns. Positive Eu anomalies (Eu/Eu^* = 1.05–1.30), variable Ce anomalies, and high Y/Ho ratios (20–28) indicate mixing between seawater-derived silica and high-temperature hydrothermal fluids, likely sourced from mafic volcanic substrates. PAAS-normalized patterns of both cherts and siliciclastics suggest limited terrigenous dilution in the ferruginous cherts but significant detrital inputs in the shales and sandstones, dominated by felsic to intermediate crustal material. Trace element ratios including Th/U, V/Cr, Ni/Co, and U concentrations collectively indicate predominantly oxic to sub-oxic depositional conditions with localized reducing microenvironments associated with Fe–Mn-rich fluids. Provenance-sensitive indicators (e.g., La/Sc, Th/Sc, Zr/Hf) in the shales and sandstones, although deposited on a passive margin, point to a continental margin affinity consistent with the erosion of the Birimian Supergroup and Pan-African granitoid sources. These geochemical signatures reveal that the Buem basin evolved under the combined influence of hydrothermal venting, silica-iron precipitation, and sustained detrital influx from adjacent continental sources. The ferruginous cherts represent the main hydrothermal imprint in the sequence, whereas the siliciclastics record broader basin-scale provenance and redox signatures. These results refine the understanding of Neoproterozoic basin dynamics in southeastern Ghana and highlight the role of hydrothermal activity in shaping chemical sedimentation within the Pan-African orogenic framework.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"45 4","pages":"878 - 912"},"PeriodicalIF":1.4,"publicationDate":"2026-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148783062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mid-Permian Luerma intraplate basalt in the southern Lhasa subterrane, Qinghai–Tibetan Plateau: Recording the initial breakup of the Lhasa terrane from northern Gondwana","authors":"Hong Liu,&nbsp;Huai Yu,&nbsp;Youguo Li,&nbsp;Hanxiao Huang,&nbsp;Hui Liu,&nbsp;Yong Huang,&nbsp;Peiqi Hu,&nbsp;Jin Zhou,&nbsp;Guoliang Xu","doi":"10.1007/s11631-026-00868-0","DOIUrl":"10.1007/s11631-026-00868-0","url":null,"abstract":"<div><p>Among the numerous scientific questions concerning the evolution of the Tethys on the Qinghai–Xizang Plateau, the initial breakup of the Lhasa terrane from northern Gondwana remains disputed. This controversy stems primarily from the scarcity of intraplate magmatic records associated with this event and insufficient systematic research into its genetic mechanisms. However, the discovery of a Mid-Permian Luerma within-plate basalt in the Western part of the Lhasa Terrane provides new evidence for the exploration of this issue. Building on U–Pb dating of zircon via laser ablation–inductively coupled plasma–mass spectrometry (LA‒ICP‒MS), the estimated age of the basalt is approximately CA. 261 ± 1 Ma. Geochemically, the rock belongs to the shoshonite–latite series and contains high levels of iron (Fe₂O₃, 4.67–5.57 wt%; FeO, 3.51–5.59 wt%), magnesium (MgO, 3.86–6.58 wt%), total alkalis (K₂O + Na₂O, 4.43–8.07 wt%), and titanium (TiO₂, 2.00–3.78 wt%). Additionally, the basalt is enriched in large-ion lithophile elements and light and heavy rare-earth elements (LREEs/HREEs) whose ratios of the samples range from 9.92 to 16.92), with no apparent Eu or Ce anomalies (<i>δ</i>Eu, 0.88–1.07 and <i>δ</i>Ce, 0.81–1.22). Isotopically, the rock exhibits high <i>ε</i>_Nd(<i>t</i>) (0.77–2.76) and <i>ε</i>_Hf(<i>t</i>) (6.60–9.00) and low (⁸⁷Sr/⁸⁶Sr)_i (0.703248–0.705597) values. These findings indicate that the basaltic magma originated from the partial melting of the upper mantle within a plate. This study revealed that the Lhasa terrane separated from northern Gondwana by at least the Mid-Permian.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"45 3","pages":"733 - 750"},"PeriodicalIF":1.3,"publicationDate":"2026-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148196233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Petrogenesis of Yanshanian granites in the Guidong complex, Northern Guangdong: Implications for uranium mineralization","authors":"Haiyang Wang,&nbsp;Changqian Ma,&nbsp;Jiayong Pan,&nbsp;Fujun Zhong,&nbsp;Fei Xia,&nbsp;Xiangping Gu,&nbsp;Guanghua Liu,&nbsp;Zhengle Chen,&nbsp;Jungang Liu,&nbsp;Jiaming Qi","doi":"10.1007/s11631-026-00870-6","DOIUrl":"10.1007/s11631-026-00870-6","url":null,"abstract":"<div><p>The Guidong complex in northern Guangdong constitutes a key segment of the Nanling Metallogenic Belt and hosts significant granite-related uranium deposits. However, the petrogenesis of the Yanshanian intrusions in its western part remains poorly constrained because of insufficient high-precision geochronological and mineralogical data. This limitation hinders a comprehensive understanding of regional metallogenesis. To address this, we conducted an integrated study of the Siqian two-mica granite and the Changping biotite granite, incorporating zircon U–Pb geochronology, whole-rock geochemistry, Hf–Nd isotope analysis, and mineral chemistry. Our objectives were to determine their emplacement ages and to investigate their petrogenesis and relationship with uranium mineralization. Zircon U–Pb dating indicates that the Siqian and Changping granites formed at 160 ± 1 Ma and 156 ± 1 Ma, respectively, suggesting both were emplaced during the Early Yanshanian magmatic event. These high-K calc-alkaline rocks are peraluminous (A/CNK = 1.04–1.44), enriched in large-ion lithophile elements (LILEs; e.g., Rb, Th, U), and depleted in high-field-strength elements (HFSEs; e.g., Ba, Nb, Ta). They exhibit negative zircon ε_Hf(t) values ranging from – 15.4 to – 8.4, with corresponding crustal model ages of 1668–2142 Ma. Whole-rock samples show ε_Nd(t) values from –11.2 to –9.1 and Nd model ages of 1693–1860 Ma. These isotopic features indicate that both plutons represent moderately differentiated S-type granites derived from partial melting of Paleo- to Mesoproterozoic metasedimentary sources (e.g., pelitic and psammitic rocks), accompanied by fractional crystallization of minerals such as ilmenite and apatite. Integrated geochemical and mineralogical data reveal that the Siqian and Changping granites are characterized by low Th/U ratios, high F contents, and low magmatic oxygen fugacity—signatures typical of U-rich granites. These attributes provided a favorable lithogeochemical environment for uranium enrichment and acted as primary sources for uranium-bearing, high-temperature hydrothermal fluids, thereby playing a critical role in regional uranium mineralization.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"45 3","pages":"554 - 575"},"PeriodicalIF":1.3,"publicationDate":"2026-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148196263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Late Carboniferous volcanic rocks in the North Tianshan Orogenic Belt, NW China: petrogenesis and tectonic implications","authors":"Jianye Zhang,&nbsp;Yongjun Li,&nbsp;Wei Li,&nbsp;Qian Wang,&nbsp;Panlong Wang,&nbsp;Hao Fu,&nbsp;Gaoxue Yang","doi":"10.1007/s11631-026-00869-z","DOIUrl":"10.1007/s11631-026-00869-z","url":null,"abstract":"<p>The North Tianshan Orogenic Belt (NTB) is a crucial region for understanding the accretionary evolution of the Central Asian Orogenic Belt. However, its Late Carboniferous tectonic setting has long been controversial. This study presents new geochronological and geochemical data on volcanic rocks to shed light on this issue. The volcanic rocks are composed of basalt, andesite, dacite, and rhyolite. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) zircon U–Pb dating yielded ages of 310.1 Ma (basalt), 304.8 Ma (andesite), 308.1 Ma and 307.0 Ma (two dacite samples), and 313.5 Ma (rhyolite). Geochemical data demonstrate that the calc-alkaline intermediate-mafic volcanic rocks (basalts and andesites) belong to co-genetic magmatic products, enriched in Ba, K, U, and Pb, and depleted in Nb, Ta, Ti, Zr, and Hf. They originated from fluid-metasomatized depleted mantle wedge. However, due to differences in subduction-related fluid input and the degree of partial melting, the intermediate-mafic volcanic rocks show slight differences in trace element composition. The I-type dacites, enriched in Ba, K, U, and Pb but depleted in Nb, Ta, and Ti, were derived from the partial melting of mafic lower continental crust. The A-type rhyolites are characterized by enrichment in Rb and Th and depletion in Ba, Sr, and P, consistent with derivation from partial melting of felsic upper continental crust. The spatiotemporal distribution patterns of regional magmatism and mineralization suggest that a ridge subduction setting was operating in the NTB during the Late Carboniferous.</p>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"45 3","pages":"506 - 529"},"PeriodicalIF":1.3,"publicationDate":"2026-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148196253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vertical distribution of redox-active sulfur and iron species in Karst Lake sediments and their implications for coupled iron–sulfur cycling","authors":"Hao Wang,&nbsp;Jian Zhu,&nbsp;Liao Peng,&nbsp;Ruyi Zheng","doi":"10.1007/s11631-026-00855-5","DOIUrl":"10.1007/s11631-026-00855-5","url":null,"abstract":"<div><p>Lake sediments are key reservoirs for sulfur (S), iron (Fe), and their associated compounds, playing a central role in the coupled Fe–S biogeochemical cycle. However, the dynamics of this cycle vary greatly among lakes with different pollution histories and redox conditions. To clarify how Fe–S cycling responds to varying geochemical environments, this study investigates the vertical distribution and speciation of multiple sulfur and iron forms, acid-volatile sulfide (AVS), elemental sulfur, Fe(III), and Fe(II), in sediments from three lakes in Guizhou, China—Maoshitou, Aha, and Hongfeng—which are characterized by distinct pollution and redox histories. We combined sequential extraction with sediment geochemical analysis to quantify the reactivity of Fe(III) and explore its role in the coupled Fe–S processes. The results show that the three lakes exhibit contrasting redox environments, leading to markedly different vertical profiles of S and Fe species. In particular, Maoshitou Lake displays unusually high concentrations of dissolved elemental sulfur, reflecting unique redox transitions in its sediments. Elevated AVS concentrations in deeper, more reducing sediments reflect active sulfate reduction and the subsequent formation of iron sulfide minerals. In these environments, solid-phase Fe(III), mainly as iron (oxyhydr)oxides, is reduced to Fe(II), which then reacts with sulfide to form FeS minerals. These results highlight that differences in lake pollution history and oxidative conditions strongly influence Fe–S coupling and the transformation pathways of reactive Fe(III) and reduced S species. The enhanced Fe(III) reactivity observed in Maoshitou Lake underscores its pivotal role in regulating Fe–S biogeochemical cycling under varying redox regimes.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"45 4","pages":"1134 - 1149"},"PeriodicalIF":1.4,"publicationDate":"2026-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148782230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatiotemporal variations in water quality and geochemical processes in an acid mine drainage-affected Karst river: Insights from multivariate water quality indices and statistical analyses","authors":"Changmei Yao,&nbsp;Yeye Ren,&nbsp;Pan Wu,&nbsp;Guangxi Long,&nbsp;Xingxing Cao","doi":"10.1007/s11631-026-00859-1","DOIUrl":"10.1007/s11631-026-00859-1","url":null,"abstract":"<div><p>Karst water serves as a crucial source of water supply in many regions worldwide, yet it remains environmentally sensitive and highly vulnerable to pollution, especially from mining activities. Understanding the spatial–temporal variations in water quality and identifying the key geochemical processes in mining-impacted karst rivers are essential for ensuring regional water security and effective environmental management. This study undertakes a karst river affected by acid mine drainage (AMD), where typical mining activities generated wastewater, using a combination of Integrated Pollution Index (P), irrigation suitability assessment, health risk assessment, and multivariate statistical analysis to elucidate the impact of mining on water quality dynamics. The results show that seasonal variation of P and irrigation suitability follows the trend: dry season &gt; flat season &gt; wet season, but health risk assessments did not show significant differences in time. Spatially, streams influenced by upstream AMD exhibited higher P and lower irrigation suitability, indicating poor water quality unsuitable for both drinking and agricultural use. In contrast, downstream water quality improved due to dilution processes. Health risk assessments identified Mn as the primary non-carcinogenic risk factor in the study area. Multivariate statistical analysis revealed that water quality variations were predominantly controlled by pH, TN, NH₃-N, SO₄²⁻, Ca²⁺, Mg²⁺, and heavy metals, all of which are closely associated with enhanced mineral weathering impacted by mining activities. These findings provide a scientific basis for targeted environmental policy-making and sustainable management strategies aimed at protecting the ecological integrity of karst river systems under mining pressure.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"45 4","pages":"1117 - 1133"},"PeriodicalIF":1.4,"publicationDate":"2026-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148782196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Emeishan basalt’s contribution to heavy metals in topsoil (notably cadmium) in Southwest China from soil geochemistry evidence","authors":"Fang Yang,&nbsp;Liang Tang,&nbsp;Yang Li,&nbsp;Bo Cheng,&nbsp;Tim T. Werner,&nbsp;Lingfei Qu,&nbsp;Ke Cheng,&nbsp;Aiming Zhang,&nbsp;Junbo Wang,&nbsp;Guikai Li","doi":"10.1007/s11631-026-00860-8","DOIUrl":"10.1007/s11631-026-00860-8","url":null,"abstract":"<div><p>While geogenic processes are believed to be an important contributor to heavy metals in topsoil, notably cadmium (Cd), an understanding of heavy metal constraints from geological formations is hindered due to a lack of large-scale soil geochemical data. Addressing this, our study analyzed 15,181 topsoil samples (0–20 cm) collected from the Sichuan Basin, southwestern China, covering ~25,500 km² of land. The results indicate that geogenic Cd is more concentrated in the topsoil of the Middle-Upper Permian (P_2-3, ~1.07 mg/kg) despite regional outcrops from Cambrian (Ꞓ_2-3, 0.52 mg/kg) to Quaternary (Q_p, 0.29 mg/kg) strata. We assume that the Emeishan basaltic lava that erupted in the Late Permian (P₃<i>e</i>) in southwest China is an understudied factor. This erupted lava probably provided essential elements and heat necessary for heavy metal accumulation in a preferred sea–continental and marine environment, eventually facilitating leaching and diffusion of the metals. Ultimately, geological exposure and pedogenesis led to elevated metals in the topsoil of P_2-3 strata.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"45 4","pages":"1102 - 1116"},"PeriodicalIF":1.4,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148781870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrogeochemical characteristics and circulation evolution of spring waters in the Nangqian Basin, Qinghai, China: Insights from multi-isotope (δ2H–δ18O–3H–δ11B) constraints","authors":"Pengcheng Zhang,&nbsp;Wenhua Han,&nbsp;Huaide Cheng,&nbsp;Yongshou Li,&nbsp;Haizhou Ma,&nbsp;Binkai Li,&nbsp;Xuehai Ma,&nbsp;Huandi Li","doi":"10.1007/s11631-025-00847-x","DOIUrl":"10.1007/s11631-025-00847-x","url":null,"abstract":"<div><p>Spring systems in tectonically active evaporite basins provide critical insights into groundwater circulation, solute sources, and geothermal potential. However, the processes controlling the hydrogeochemical evolution of springs in the Nangqian Basin, located in the southeastern Qinghai–Tibetan Plateau, remain insufficiently understood. In this study, we collected a comprehensive dataset of 20 spring and river water samples during both wet and dry seasons in 2022, encompassing saline, hot, and cold springs. Major and trace elements were analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS), while hydrogen, oxygen, tritium, and boron isotopes were determined through isotope ratio mass spectrometry and liquid scintillation counting. The results indicate that saline springs are characterized by high concentrations of Na⁺, Cl⁻, Ca²⁺, and SO₄²⁻, which suggest dominant evaporite dissolution. In contrast, hot springs exhibit significantly elevated silica contents and reservoir temperatures exceeding 130 °C. The stable isotopic compositions plot near the local meteoric water line, and tritium activity (3.6–26.4 TU) indicate modern meteoric recharge, which is generally considered to have residence times of less than 60 years. Most boron isotope ratios (−8.12‰ to intermediate values) suggest continental depositional characteristics, whereas isolated high ratios, such as +28‰, likely record marine evaporite influences; these variations also reflect isotopic fractionation during deep groundwater circulation. Estimated circulation depths range from approximately 1300 m in cold springs to over 4200 m in hot springs, reflecting contrasting flow paths and structural controls. Integrated geochemical and isotopic evidence supports a conceptual model wherein meteoric water infiltrates along faults and fractures, undergoes extensive water–rock interaction with evaporitic and silicate strata, and variably mixes with ascending geothermal fluids before discharge. These findings enhance the understanding of hydrogeochemical processes in high-altitude evaporite basins and provide a scientific basis for groundwater resource management and geothermal exploration in the Nangqian Basin.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"45 4","pages":"1085 - 1101"},"PeriodicalIF":1.4,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148782039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}