Acta Geochimica最新文献

{"title":"Isotopic characterization (δ18O, δD and d-excess) and modelling of stream flow partitioning along an altitudinal gradient in the Satluj River basin (SRB) Himalayan-alluvial plain using end member mixing analysis (EMMA) and associated uncertainty","authors":"Akhtar Jahan, Nachiketa Rai, M. U. Khan, Tanveer Dar, Sudhir Kumar","doi":"10.1007/s11631-025-00782-x","DOIUrl":"10.1007/s11631-025-00782-x","url":null,"abstract":"<div><p>Stable isotopic (<i>δ</i><sup>18</sup>O, <i>δ</i>D and <i>d</i>-excess) signatures were employed to gain valuable insights regarding key hydrological processes and modelling of stream flow runoff partitioning of Satluj River Basin (SRB) in the western Himalayan region and plains of Punjab, where surface water is extensively used for hydropower, agricultural and domestic supply. The SRB has not yet been unexplored. Spatially extensive and comprehensive stable isotope data are meagre, which constricts the thoughtful comprehension of hydrological processes, sources of moisture, the isotope-elevation relationship and provenance quantification in this transboundary river across the mountain-plain basin. The results showed a significant difference in <i>δ</i><sup>18</sup>O, <i>δ</i>D and <i>d</i>-excess among the main stream, tributaries and groundwater during the observed period, mainly regulated by snow-glacier melt input, evaporation and recycled moisture contribution. The deviation of the water line in each hydrological compartment from the Global Meteoric Water Line, as well as its similarity to the local, regional and local water lines, suggests that these compartments have undergone significant evaporation during the recharge process. This similarity in moisture dynamics implies a potential link between the local and regional hydrological systems. The isotopic signature integrated with back trajectories reflects the combined role of moisture sources via both westerlies and southwest monsoons followed by extensive local recycling. The isotopic altitude lapse rate (IALR) of the various hydrological compartments mimics the IALR results from the Himalayas and their surrounding catchments. Moreover, the isotopic composition (<i>δ</i><sup>18</sup>O) of the main stream showed a closer fit to a second-order polynomial relationship between <i>δ</i><sup>18</sup>O and elevation compared to other models. Furthermore, we employ end member mixing analysis (EMMA) principles to identify the possible end members and calculate contributing fractions for respective end members. Modelling of stream flow partitioning using a dual isotopic tracer (<i>δ</i><sup>18</sup>O-<i>EC and δ</i><sup>18</sup>O-<i>d</i> mixing model) based EMMA revealed the three possible end members, namely glacier melt, snow melt and groundwater, contributing 29.5%, 31.7% and 38.7%, respectively, via a <i>δ</i><sup>18</sup>O-EC mixing model, while 29.6%, 31.3% and 39.0%, respectively, via a <i>δ</i><sup>18</sup>O-<i>d</i> mixing model. The mathematically propagated uncertainty in the respective computed mixing fractions of EMMA is approximately 28%, 41% and 25% with the <i>δ</i><sup>18</sup>O-EC mixing model and 19%, 54% and 35% with the <i>δ</i><sup>18</sup>O-<i>d</i> mixing model, respectively, reflecting realistic uncertainties. An attempt is made to acknowledge, explore and hypothesize the realistic reason for the larger documented uncertainty. The study highlights the significant ","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"45 4","pages":"1055 - 1084"},"PeriodicalIF":1.4,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148782279","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":"Titanium partitioning between pyroxenes and lunar basaltic melts: An experimental perspective","authors":"Huan Gong,&nbsp;Jing Yang,&nbsp;Wei Du","doi":"10.1007/s11631-025-00802-w","DOIUrl":"10.1007/s11631-025-00802-w","url":null,"abstract":"<div><p>The size of basalt fragments in Chang’E-5 (CE-5) regolith are small (&lt; 6 mm²), resulting in large variation on the estimated bulk composition of CE-5 basalt. For example, the estimated TiO₂ content of CE-5 basalt ranges from 3.7 wt% to 12.7 wt% and the Mg# (molar percentage of Mg/[Mg + Fe]) also shows a wide range (26.2 − 42.4). Preliminary experimental studies have shown that these geochemical characteristics of CE-5 basalt are critical for investigating the crystallization sequence and formation mechanism of its parent magma. This study presents new experimental data on the distribution coefficient of titanium between pyroxene and lunar basaltic magma <span>(left( {{text{D}}_{{{text{Ti}}}}^{{text{Px/melt}}} } right))</span>. Combining with available literature data, we confirm that <span>({text{D}}_{{{text{Ti}}}}^{{text{Px/melt}}})</span> is affected by crystallization conditions such as pressure and temperature, but it is mainly controlled by the CaO content of pyroxene. Comparing with previous experimental results under similar conditions, we parameterized the effect as <span>({text{D}}_{{{text{Ti}}}}^{{text{Px/Melt}}} {text{ = D}}_{{{text{Ti}}}}^{{text{Px/Melt}}} { ;= - 0}{text{.0005X}}_{{{text{Cao}}}}^{{2}} { ;+; 0}{text{.0218X}}_{{{text{CaO}}}} { ;+; 0}{text{.0425} ({text{R}}^{2} = 0}{.82)})</span><span>(text{,})</span>where X_CaO is the CaO content in pyroxene in weight percentage. The new experimental results suggest that pyroxene with high TiO₂ content (&gt; 2.5 wt%) in CE-5 basalt is not a product of equilibrium crystallization, and the CaO content in pyroxene is also affected by cooling rate of its parent magma. The TiO₂ content in the CE-5 parent magma is estimated to be about 5 wt% based on the Mg# of pyroxene and its calculated CaO content, which is consistent with those estimated from olivine grains.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 on","pages":"931 - 944"},"PeriodicalIF":1.3,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145284291","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 evolution, natural background level quantification, quality assessment of groundwater using integrated entropy and CRITIC weighing methods based water quality index (IWQI), and health risk assessment in the middle Gangetic Plain, India","authors":"Akhtar Jahan,&nbsp;Nachiketa Rai,&nbsp;M. U. Khan,&nbsp;Tanveer Ali Dar","doi":"10.1007/s11631-025-00784-9","DOIUrl":"10.1007/s11631-025-00784-9","url":null,"abstract":"<div><p>The Kanpur Nagar is an economically and industrially vibrant area situated on the Middle Gangetic alluvial plain which lacks robust hydrogeochemical data. Therefore, in the present research, hydrogeochemical techniques integrated with multi-statistical analysis were used to assess the geochemistry, sources of ions, geochemical evolution, natural background levels (NBLs), threshold values (TVs), and suitability for drinking purposes using the integrated-weight water quality index (IWQI) of 68 groundwater samples from both pre-monsoon (PRM) and post-monsoon (POM) seasons. Additionally, an assessment was made of the sources and occurrence of fluoride and nitrate contaminants in the groundwater, followed by an evaluation of their associated non-carcinogenic human health risks (NCHHR) due to the oral consumption of F⁻, and NO⁻₃. Silicate weathering was found to be the most influential geochemical process in the study area, followed by active cation exchange, with a significant contribution from anthropogenic sources. The study assessed the identification of geochemical factors that control high levels of chemical components in groundwater using NBLs and TVs. Values of IWQI indicate the occurrence of excellent and good quality potable water in 78% and 91% of the total groundwater samples from PRM and POM, respectively. As per the geochemical signature, the probable source of excess fluoride might be related to the interaction of groundwater with alluvial sediments deposited in the geological past, while agronomic sources could be the sole reasons for elevated nitrate concentration. It was found that children are more prone to NCHHR than the adult population, as per the calculated total hazard index.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"45 2","pages":"256 - 297"},"PeriodicalIF":1.3,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147734893","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":"A review of integrated groundwater and surface water management for environmental sustainability","authors":"Nishi Kant,&nbsp;Gyan Wrat","doi":"10.1007/s11631-025-00803-9","DOIUrl":"10.1007/s11631-025-00803-9","url":null,"abstract":"<div><p>This review critically examines strategies for sustainable groundwater and surface water management, emphasizing their integration to achieve environmental sustainability. The study synthesizes findings from a wide range of research articles, identifying key trends, gaps, and controversies within the field. It highlights the importance of cohesive management approaches that take into account climate change, policy impacts, and methodological advancements. The review aims to provide a structured, analytical discussion that aligns with the thematic focus of integrated water management. By offering original insights and practical recommendations, this review seeks to contribute to the development of more effective and sustainable water management practices. The analysis underscores the necessity of interdisciplinary approaches that integrate hydrological, ecological, and socio-economic factors. Furthermore, the review discusses the role of adaptive management and technological innovations in enhancing the resilience and efficiency of water management systems. The findings suggest that a comprehensive understanding of the interactions between groundwater and surface water is crucial for developing strategies that ensure long-term environmental sustainability. This review concludes with recommendations for future research and policy development, emphasizing the need for adaptive, resilient, and integrated water management strategies that can address the challenges posed by climate change and other environmental pressures.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 on","pages":"1120 - 1141"},"PeriodicalIF":1.3,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145284220","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":"Deep geological processes of the early Middle Jurassic granitic complexes in the Songjianghe area, Jiapigou-Haigou collage zone, Northeast China: Evidence from zircon U–Pb dating, elemental geochemistry and Sr–Nd–Hf isotopes","authors":"Xinwen Zhang,&nbsp;Jinggui Sun,&nbsp;Zuochao Lin,&nbsp;Shu Wang,&nbsp;Yunpeng He","doi":"10.1007/s11631-025-00793-8","DOIUrl":"10.1007/s11631-025-00793-8","url":null,"abstract":"<div><p>The deep geologic processes between the Xing’an-Mongolian Orogenic Belt and the North China Craton in the Mesozoic are crucial to reveal the magmatic and tectonic evolution and their constraints on mineralization in the Jiapigou-Haigou collage zone. In this paper, We have presented the geochronology, geochemistry and Sr–Nd–Hf isotopic compositions of the Middle Jurassic granitic complexes in the Songjianghe area, Jilin Province. The granitic complexes can be categorized into four groups based on their geologic characteristics, with corresponding zircon U–Pb isotope ages of 177 Ma, 172 Ma, 169 Ma and 168–167 Ma, respectively. These granitoids exhibit calc-alkaline to high-K calc-alkaline, metaluminous to weakly peraluminous I-type characteristics, which show relative enrichment in LILEs (Rb, Sr, Ba) and depletion in HFSEs (Nb, Zr). Geochemical analyses reveal high initial ⁸⁷Sr/⁸⁶Sr ratios of 0.70633–0.70740, coupled with low εNd(t) values ranging from −10.65 to −13.23. The zircon analyses show similarly negative εHf(t) values ranging from −16.9 to −3.2. The integrated elemental and Hf–Sr–Nd isotopic signatures demonstrate that the primitive magmas of the four group rocks were primarily derived from partial melting of thickened Archean lower crust, with the exception of the Group IV rocks, which exhibit significant evidence of crustal contamination. The residual mineral assemblages during the magma-forming process varied from amphibole to eclogite facies. These findings indicate that magmatism in the Songjianghe region likely resulted from the accretion and delamination of the Archean crust in the collage zone during the subduction of the Paleo-Pacific Plate beneath the Eurasian continent.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 6","pages":"1308 - 1327"},"PeriodicalIF":1.3,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145646287","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":"U–Pb zircon geochronology constraints on the contractional and extensional tectonics along the South Tibetan detachment system (STDS), Dhauliganga Valley, NW Himalaya","authors":"G. Deshmukh,&nbsp;A. K. Jain,&nbsp;P. K. Mukherjee,&nbsp;A. K. Singh,&nbsp;R. Dixit,&nbsp;Pankaj Kumar","doi":"10.1007/s11631-025-00798-3","DOIUrl":"10.1007/s11631-025-00798-3","url":null,"abstract":"<div><p>The South Tibetan detachment system (STDS), a dominant extensional fault system in the Himalayan orogen, separates the Greater Himalayan Sequence from the overlying Tethyan Himalayan Sequence in the north. Along the Dhauliganga Valley, NW Himalaya, folded psammitic gneisses in the immediate footwall of the STDS yield a Neoproterozoic ~ 1075 Ma U–Pb detrital zircon population and are intruded by Cambro-Ordovician granitoids. This is followed by protracted magmatism during the Late Eocene–Middle Miocene. In addition to structural analysis and deformation fabric studies, the timing of activity along the South Tibetan Detachment System can be constrained by U–Pb zircon geochronology ages of pre-, syn- and post-tectonically deformed and undeformed leucogranite bodies. The concordant leucogranites inherit the Neoproterozoic zircons from the footwall high-grade gneisses during their partial melting. Late Eocene migmatization and melt intrusion (~38–34 Ma) were coeval with Barrovian metamorphic, followed by Late Oligocene extension-induced exhumation. The U–Pb zircon geochronology of leucogranites within the uppermost Greater Himalayan Sequence show Late Eocene–Early Oligocene (35–23 Ma) magmatism. Evidence of Late Eocene (35.3 ± 1.8 Ma) SW-directed contraction, crustal thickening and associated metamorphism is observed in gneisses exhibiting tight isoclinal folds with NE-dipping axial surfaces. The transition from contractional to extensional tectonics might have likely occurred in the Late Oligocene–Early Miocene (24–21 Ma), followed by extension-induced exhumation. Leucogranite emplacement ceased along the South Tibetan Detachment System during the Middle Miocene (17.77 ± 0.61 Ma) and tectonic activity subsequently migrated southwards.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"45 4","pages":"985 - 1004"},"PeriodicalIF":1.4,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148781944","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":"Mineralogy, geochemistry, and stable isotopes in the reconstruction of the paleodepositional environment, provenance, and paleoclimate of Cretaceous mudstones, Koum Basin, Cameroon","authors":"Nowel Yinkfu Njamnsi,&nbsp;George Lemewihbwen Ngiamte,&nbsp;Cheo Emmanuel Suh,&nbsp;Olivier Anoh Njoh,&nbsp;Daniel Layton-Matthews,&nbsp;Peir K. Pufahl,&nbsp;Agatha Dobosz","doi":"10.1007/s11631-025-00800-y","DOIUrl":"10.1007/s11631-025-00800-y","url":null,"abstract":"<div><p>The Cretaceous Koum Basin is a rift-related half-graben in northern Cameroon, which constitutes a portion of the Yola Arm of the Upper Benue Trough. This study presents the first comprehensive dataset combining mineralogical, bulk-rock geochemical, and stable C–H–O isotopic data for dark-gray, fine-grained mudstones from the basin, providing new insights into its sediment source, paleoenvironment, and geodynamic setting. The mudstones primarily consist of phyllosilicates (~ 8.6%), feldspars (~ 30.5%), carbonates (~ 13.7%), and minor iron oxides (~ 2.7%), with vermiculite, illite, and kaolinite as the main clay minerals. The presence of analcime, ankerite, and dolomite suggests low-grade metamorphism and/or hydrothermal alteration. Fe₂O₃/K₂O (1.52–6.40) and SiO₂/Al₂O₃ (2.97–4.68) ratios classify the mudstones as compositionally immature shales (ICV ~ 1.64) with low-moderate chemical weathering (CIA ~ 56.35; PIA ~ 59.74; R³⁺/R³⁺ + R²⁺ + M⁺  ~ 0.51). Trace element ratios (Th/Sc ~ 1.70, Zr/Sc ~ 1.33, La/Sc ~ 6.30, La/Th ~ 4.14) indicate an intermediate igneous provenance from a continental crustal source. Paleoenvironmental proxies suggest deposition in a dynamic basin environment marked by fluctuating redox (C_org/P: 0.21–178.34) and salinity (Sr/Ba: 0.34–3.25; N-values: 48–35.92) conditions, ranging from oxic to anoxic and brackish to saline. Major element data (SiO₂ vs. Al₂O₃ + K₂O + Na₂O) indicate a semi-arid regime, while Paleoclimatic indicators such as Sr/Cu (1.88–37.47) and C-values (0.12–0.93) suggests alternating humid and arid conditions. Notably, stable isotope data, reported here for the first time in the Koum Basin, reveal a predominantly terrestrial, fluvial-deltaic C₃ plant source for organic carbon (<i>δ</i>¹³C − 25.2‰ to − 35.2‰) and complex fluid-rock interactions involving meteoric and magmatic-metamorphic fluids under a warm, equatorial climate (<i>δ</i>¹⁸O + 3.6‰ to + 24.9‰, <i>δ</i>²H − 104‰ to − 50‰). The combined mineralogical, geochemical, and isotopic data point to deposition in a tectonically active continental arc setting, with contributions from ocean island arc and passive margin sources.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 on","pages":"1014 - 1039"},"PeriodicalIF":1.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145284268","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":"Petrography, geochemistry, and zircon U–Pb chronology of the Late Ordovician metavolcanic suites in the eastern North Qilian orogenic belt, NW China: constraints on their petrogenesis and tectonic implications","authors":"Irshad Hussain,&nbsp;Zuochen Li,&nbsp;Xianzhi Pei,&nbsp;Lei Pei,&nbsp;Feng Gao,&nbsp;Mao Wang,&nbsp;Xiao Wang,&nbsp;Hao Lin,&nbsp;Li Qin,&nbsp;Shang Ji","doi":"10.1007/s11631-025-00796-5","DOIUrl":"10.1007/s11631-025-00796-5","url":null,"abstract":"<div><p>The study area is situated in the Tianshan region, specifically within the eastern segment of the North Qilian Orogenic Belt (NQLOB). The NQLOB is a critical region for understanding oceanic closure and continental collision processes driven by the Shangdan Ocean subduction-exhumation, which was a segment of the Proto-Tethys Ocean during the Early Paleozoic. Despite significant research, the Early Paleozoic tectonic background and subduction-related orogenic processes, particularly in the eastern NQLOB, remain subjects of debate. This study presents significant petrographic, geochemical, and geochronologic insights into the metavolcanic rocks of the Chenjiahe Group in the eastern NQLOB. Petrographic analysis reveals that these metavolcanic rocks originated in a low-grade metamorphic setting. Zircon laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U–Pb dating yielded ages ranging between 449.7–443.4 Ma, indicating Late Ordovician formation. Geochemical signatures of felsic and intermediate rocks exhibit calc-alkaline to high-K calc-alkaline similarities, characterized by high light rare earth elements (LREEs), low heavy rare earth elements (HREEs), and moderate Eu anomalies, consistent with a continental arc setting. In contrast, basaltic rocks display tholeiitic features with elevated large-ion lithophile elements (LILEs), reduced high-field-strength elements (HFSEs), and weak Eu anomalies, suggesting an extensional environment. These findings imply that the metavolcanic rocks evolved in a continental arc-back-arc extension setting connected with the northward subduction and exhumation of the Huluhe back-arc oceanic basin. This process was likely triggered by the northward subduction and closure of the Shangdan Ocean, culminating in the Late Ordovician amalgamation of the Qilian Block and the southwestern North China Block. This study provides critical insight into the tectonic development of the NQLOB and the broader Proto-Tethys Ocean dynamics at the northern periphery of the Eastern Gondwana.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 4","pages":"759 - 783"},"PeriodicalIF":1.3,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145170067","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":"Trace element geochemistry of dispersed organic matter in Western Mecsek uranium ore deposit, Southern Hungary","authors":"Medet Junussov,&nbsp;Maxat Kembayev,&nbsp;Nessipzhan Mukhamediyarova,&nbsp;Murat Maratuly Rustembekov,&nbsp;Rustem Abirov","doi":"10.1007/s11631-025-00801-x","DOIUrl":"10.1007/s11631-025-00801-x","url":null,"abstract":"<div><p>This paper provides analytical insights into the geochemical composition, particularly focusing on gold, of dispersed organic matter (DOM) mainly present within vitrinite and solid bitumen. This DOM is closely associated with uranium ores located within the Late Permian Kővágószőlős Sandstone Formation in Western Mecsek, South-West Hungary. The presence of DOM is notable in the uranium-rich formation of the deposit. However, crucial aspects such as its morphological characteristics, trace element composition, and its relationship with ore minerals are still largely unexplored. The study utilizes a range of techniques, including optical microscopic analysis, maceral and vitrinite reflectance analyses; and trace element measurement using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The analytical data show that DOM has six different morphologies: primary vitrinite, secondary (reworked) vitrinite, inertinite, solid bitumen, pyrobitumen, and graphite. Vitrinite reflectance of DOM ranges from 1.7% to 2.9%. The DOM has average content of Au 0.67 ppm, Ag 7.7 ppm, U 58.8 ppm and Th 22 ppm, As 256 ppm, Cu 91 ppm, Ni 61 ppm, and P 259 ppm. We conclude that DOM exhibits elevated levels of gold and uranium, likely attributed to its deposition under reducing conditions. These findings support the potential use of DOM's trace element composition as an indicator of the formation conditions of ore mineralization. Specifically, our data suggest that using LA-ICP-MS to analyze trace elements, within DOM could serve as a valuable exploration tool within the Kővágószőlős Sandstone Formation in the Western Mecsek deposit.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"45 5","pages":"1475 - 1492"},"PeriodicalIF":1.4,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149098727","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":"Prolonged mantle metasomatism in the Neoproterozoic continental arc: Insights from mafic magmatism in the western Yangtze Block, South China","authors":"Zhe-hao Zhong,&nbsp;Shao-cong Lai,&nbsp;Yu Zhu,&nbsp;Jiang-feng Qin,&nbsp;Ren-zhi Zhu,&nbsp;Min Liu,&nbsp;Yu-hong Xia","doi":"10.1007/s11631-025-00791-w","DOIUrl":"10.1007/s11631-025-00791-w","url":null,"abstract":"<div><p>Mafic rocks generated from subduction settings have recorded valuable source information about the mantle source. In this study, we present a comprehensive analysis of zircon U–Pb dating, whole-rock major and trace elements, and Sr–Nd isotopic data for the mafic gabbro located in the Yumen area, on the western part of the Yangtze Block, South China, aiming to constrain the processes of mantle metasomatism within subduction settings. U–Pb dating results for zircon yield crystallization ages of 800 Ma for type 1 mafic gabbro and 753–734 Ma for type 2 mafic gabbro. Type 1 mafic gabbro exhibits higher SiO₂ (44.13%–48.93%) and Al₂O₃ content but lower total Fe₂O₃ and MgO content than type 2 gabbro (SiO₂: 41.02%–43.28%). These gabbros display a high-Mg^# signature (52.50–62.81 for type 1, 50.89–57.04 for type 2), while they are enriched in significant large-ion lithophile elements (LILEs: Rb, Ba, Sr, K) and depleted in high-field-strength elements (HFSEs: Zr, Hf, Nd, Ta, Ti), which indicates an arc-like element signature. The positive whole-rock εNd(t) values (type 1: 3.5–4.4, type 2: 5.6–6.3) combined with a narrow range of (⁸⁷Sr/⁸⁶Sr)_i (type 1: 0.7035–0.7043, type 2: 0.7035–0.7036) of both gabbro types suggest a depleted lithospheric mantle origin. Therefore, these mafic rocks may derive from a metasomatized spinel lherzolite mantle source (with amphibole) due to the interactions of the deep mantle source and subduction fluid materials. We propose that the long-term metasomatism recorded by mafic gabbro in this study supports the fact that the subduction during the Neoproterozoic contributed to the formation of a metasomatized mantle source in the Yumen area, western Yangtze Block, South China.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 4","pages":"844 - 857"},"PeriodicalIF":1.3,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145167985","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}