Geoscience frontiers最新文献

{"title":"Artificial intelligence and global carbon inequality: Addressing the challenges and opportunities for SDG 10, SDG 12, and SDG 13","authors":"Qiang Wang ,&nbsp;Yufang Li ,&nbsp;Ugur Korkut Pata ,&nbsp;Rongrong Li","doi":"10.1016/j.gsf.2025.102072","DOIUrl":"10.1016/j.gsf.2025.102072","url":null,"abstract":"<div><div>This study examines the impact of artificial intelligence (AI) on carbon inequality (CI) in 67 countries from 1995 to 2019. The results suggest that (i) AI significantly amplifies CI both between and within countries due to its energy requirements and uneven deployment; (ii) trade openness and global value chain (GVC) positioning mitigate AI’s effect on inter-country CI, while robust governance—marked by larger government size and institutional transparency—curtails intra-country disparities; (iii) specific thresholds (trade openness &gt; 4.74, GVC position &gt;  −1.07, government size &gt; 2.90, transparency &gt;  −0.22) shift the impact of AI from exacerbating to reducing CI. The adverse effects of AI can be reversed through enhanced trade, GVC integration, and strong governance. Key policy implications: Policymakers must prioritize exceeding these thresholds to leverage AI for sustainable and equitable outcomes. This requires (a) promoting trade liberalization to spread the benefits of AI globally, reducing inter-country CI; (b) strengthening GVC participation to offset the carbon-intensive use of AI; (c) building government capacity and transparency to ensure fair adoption of AI domestically; and (d) embedding these strategies in climate policies to align AI with the long-term goals of environmental justice and the SDGs, particularly climate action (SDG 13) and reducing inequalities (SDG 10).</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 4","pages":"Article 102072"},"PeriodicalIF":8.5,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144069487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 and tectonic implications of peridotites of the Shangla Complex Ophiolite along Main Mantle Thrust, Northern Pakistan","authors":"Zaheen Ullah ,&nbsp;Asad Khan ,&nbsp;Huan Li ,&nbsp;Tehseen Zafar ,&nbsp;Asghar Ali ,&nbsp;Muhammad Farhan ,&nbsp;Zahid Hussain ,&nbsp;Adnan Khan ,&nbsp;Muhammad Idrees ,&nbsp;Muhammad Ibrar","doi":"10.1016/j.gsf.2025.102070","DOIUrl":"10.1016/j.gsf.2025.102070","url":null,"abstract":"<div><div>The Shangla Complex ophiolite represents a relic of the Neo-Tethyan oceanic lithosphere along the Indus Suture Zone (also known as the Main Mantle Thrust) in northern Pakistan. This section, thrust onto the continental margin between the Indian and Karakoram (Asian) plates, is predominantly composed of depleted harzburgites, dunites and chromitites. In this study, we conducted a thorough analysis of mineralogy, whole-rock geochemistry (major oxides, trace elements, PGE), and integrated Re-Os isotopic data from mantle-derived peridotites to understand their petrogenesis and melt evolution. These peridotites exhibit a depleted nature, characterized by a low modal composition of clinopyroxene, a wide forsterite content range in olivine (86.5 to 95.2), and a large variation in Cr# values (25.1–91.4). Their diverse whole-rock geochemistry further suggests varying degrees of partial melting. The Cpx-harzburgites show high average Al₂O₃ (1.83 wt.%), CaO (2.27 wt.%), ΣREE (12.9 ppb), and ¹⁸⁷Os/¹⁸⁸Os values between 0.13095 and 0.12571. On the other hand, the depleted harzburgites and dunites exhibit lower average Al₂O₃ (0.57 wt.% and 0.14 wt.%, respectively), CaO concentration (0.59 wt.% and 0.21 wt.%, respectively), and ∑REE concentrations, measured at 12.7 ppb and 8.9 ppb, respectively. The ¹⁸⁷Os/¹⁸⁸Os ratios in the depleted harzburgites and dunites range from 0.12643 to 0.11777, indicating they are less radiogenic compared to the Cpx-harzburgites. The spoon-shaped rare earth elements (REE) patterns suggest that the Cpx-harzburgites underwent low degrees of partial melting (∼10%–15%), whereas the depleted harzburgites and dunites indicate somewhat higher degrees of partial melting (additional melting of the Cpx-harzburgites). The PGE abundances in these depleted harzburgites and dunites are linked to the partial melting of Cpx-harzburgites, resulting in a boninitic-like melt. Their low degree of melting and melt extraction suggests that Cpx-harzburgites initially formed at a mid-ocean ridge (MOR) spreading center or a distal fore-arc basin. In contrast, the depleted harzburgites and dunites were formed during a second phase of melting, followed by refertilization, closely associated with a supra-subduction zone (SSZ) setting. The Re-Os isotopic systematics of the Shangla Complex peridotites reveal model age clusters of ca. 250 Ma and ca. 450 Ma, potentially corresponding to significant tectonic events in the geodynamic evolution of the Neo-Tethyan, Rheic, and Proto- Tethyan oceans.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 4","pages":"Article 102070"},"PeriodicalIF":8.5,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143924381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heavy Si isotope compositions of subduction zone fluids controlled by fluid-rock interaction and fluid evolution","authors":"Kun Chen ,&nbsp;Yi-Xiang Chen ,&nbsp;Hui-Min Yu ,&nbsp;Hans-Peter Schertl ,&nbsp;Tatsuki Tsujimori ,&nbsp;Sergei Skuzovatov","doi":"10.1016/j.gsf.2025.102071","DOIUrl":"10.1016/j.gsf.2025.102071","url":null,"abstract":"<div><div>Jadeitites are formed either through direct precipitation from Na-Al-Si rich fluids (P-type), or by replacement of magmatic protoliths (R-type) in subduction zones. They are valuable targets for investigating the mobility behavior and chemical composition of subduction zone fluids. The Rio San Juan Complex (RSJC) in the northern Dominican Republic hosts both P- and R-type jadeitites and jadeite-rich rocks, which provide ideal samples for addressing such issues. Here, we present trace element and Sr-Nd-O-Si isotope compositions of RSJC jadeitites and related rocks. Most samples show similar REE patterns, trace element distributions and <em>δ</em>¹⁸O values to those of plagiogranite protoliths, indicating the predominance of R-type origin in RSJC. The P-type samples exhibit slightly higher <em>δ</em>³⁰Si values (−0.15‰ to 0.25‰) than that of R-type samples (−0.20‰ to 0.08‰), which place above the igneous array. The low (⁸⁷Sr/⁸⁶Sr)_i (0.70346 to 0.70505) and high <em>ε</em>_Nd(<em>t</em>) values (4.6 to 6.8) of the P-type jadeitites and quartzites, along with relatively low <em>δ</em>¹⁸O values (4.7‰ to 6.4‰) of their forming fluids, indicate that the fluids are likely derived from the altered basaltic crust rather than from oceanic sediment. However, the estimated jadeitite- and quartzite-forming fluids exhibit distinct <em>δ</em>³⁰Si values (0.76‰ to 0.99‰ and –0.48‰ to –0.08‰, respectively), implying an evolution of the fluids that modified the Si isotopic compositions. Since fluid metasomatism and related desilication process could have lowered the whole-rock <em>δ</em>³⁰Si values, the heavy Si isotope compositions of the R-type samples are produced from the external fluids. Combing Rayleigh distillation and binary mixing simulations, we propose that fluids derived from altered oceanic crust obtained high <em>δ</em>³⁰Si values after crystallization of minerals enriched in light Si isotopes. The P-type jadeitites are formed through direct precipitation from this fluid. As the plagiogranite protoliths were continuously replaced by this fluid, the formed R-type samples (jadeitites and quartzites) also exhibit high <em>δ</em>³⁰Si values. Such rocks could significantly alter the Si isotope compositions of local mantle when they are deeply subducted at convergent plate margins.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 4","pages":"Article 102071"},"PeriodicalIF":8.5,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phosphorite deposits: A promising unconventional resource for rare earth elements","authors":"Shamim A. Dar ,&nbsp;V. Balaram ,&nbsp;Parijat Roy ,&nbsp;Akhtar R. Mir ,&nbsp;Mohammad Javed ,&nbsp;M. Siva Teja","doi":"10.1016/j.gsf.2025.102044","DOIUrl":"10.1016/j.gsf.2025.102044","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The green energy transition relies heavily on critical metals, such as rare earth elements (REEs). However, their reserves are primarily focused in a few countries, such as China, which accounts for approximately 70% of global production. Hence, several countries are currently looking for alternative resources for REEs. Alternative REE resources in the supply chain include recycling of e-waste, industrial waste like red mud and phosphogypsum, coal ash, mine tailings, ocean floor sediments, and even certain types of sedimentary deposits like phosphorites where REEs are present in lower concentrations but at larger volumes compared to primary ore deposits which are becoming targets by REEs industry. Currently, several studies are going on the development of eco-friendly REEs extraction technologies from phosphorite deposits. Consequently, advanced data analysis tools, such as Machine Learning (ML), are becoming increasingly important in mineral prospectivity and are rapidly gaining traction in the earth sciences. Phosphorite deposits are mainly used to manufacture fertilizers as these rocks are known for their significant phosphorus content. Moreover, these formations are considered a prospective resource of REEs. The different types of phosphorite deposits such as continental, seamount, and ore deposits worldwide reported concentrations of ∑REE upto 18,000 µg/g. Due to the augmented claim of REEs for various ultra-modern, and green technology applications that are required to switch over to a carbon–neutral environment, these phosphorite deposits have become an important target mostly because of their relatively higher content of REEs especially heavy rare earth elements (HREE). For example, Mississippian phosphorites reported ∑HREE 7,000 µg/g. To have a comprehensive understanding of the REEs potential of these phosphorite deposits which also include several Chinese phosphorite deposits, this study is undertaken to review the phosphorite deposits in the world and their REEs potential, in addition to some of the associated aspects such as applications and formation mechanisms for different types of phosphorite deposits such as igneous phosphate deposits, sedimentary phosphorite deposits, marine phosphorite deposits, cave phosphate deposits, and insular guano deposits. Other important aspects include their occurrences, types, geochemical characteristics, the REEs enrichment mechanisms, and various recovery methods adopted to recover REEs from different phosphorite deposits. The present review paper concludes that the recent studies highlight the global potential of phosphorite deposits to satisfy the increasing demand for REEs. Extracting REEs from phosphorite presents no significant technological or environmental difficulties, as long as radioactive elements are eliminated. In India, more comprehensive geological surveys, along with the advancement of new methods and evaluations, are required to locate phosphorite deposits with high conc","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 3","pages":"Article 102044"},"PeriodicalIF":8.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143895134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Early Cretaceous columnar basalts from the Mesoarchean Coorg Block, Southern India: A potential plume-influenced rifting event or a localized magmatic phenomenon?","authors":"S.G. Dhanil Dev ,&nbsp;Pooja Pradeep ,&nbsp;Chengxue Yang ,&nbsp;Anoop Sooraj ,&nbsp;P.K. Krishnaprasad ,&nbsp;K.V. Sarath","doi":"10.1016/j.gsf.2025.102058","DOIUrl":"10.1016/j.gsf.2025.102058","url":null,"abstract":"<div><div>The role of mantle plume in the final stages of rifting of the East Gondwana crustal fragments remains equivocal with only limited evidence so far reported from the southern part of Peninsular India. Here, we report for the first time a suite of columnar basalts from the Mesoarchean Coorg Block in the Southern Granulite Terrain (SGT) of India and characterize these rocks through field, petrological, geochemical, and isotope geochronological studies. The basalts show porphyritic texture with phenocrysts of pyroxene and plagioclase embedded in fine groundmass. Geochemical data reveal tholeiitic flood basalt affinity with affinities of plume-related magmatism. The zircon U-Pb data of the rocks yield a weighted mean age of 137 Ma, thus corresponding to the Valanginian Age of the Early Cretaceous Period. We suggest the possible geochemical affinity of the studied rocks Kerguelen plume basalts which provide new insights into magmatism associated with the final stages of East Gondwana rifting.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 4","pages":"Article 102058"},"PeriodicalIF":8.5,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143928616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Zinc and cadmium isotope signatures: Insights into ore genesis and exploration strategies at the Xiaohongshilazi Pb-Zn-(Ag) deposit, Northeast China","authors":"Huchao Ma ,&nbsp;Da Wang ,&nbsp;Ryan Mathur ,&nbsp;Gaotian Wang ,&nbsp;Feng Bai","doi":"10.1016/j.gsf.2025.102054","DOIUrl":"10.1016/j.gsf.2025.102054","url":null,"abstract":"<div><div>The Jizhong–Yanbian Cu-Mo-Au-Pb-Zn polymetallic metallogenic belt is a major nonferrous and precious metal resource base in Northeastern China. The genesis of ore deposits in this district has remained controversial. To constrain ore genetic models and provide information for exploration, we conducted precise Zn-Cd isotopic measurements on sphalerite and galena. The <em>δ</em>⁶⁶Zn_AA–ETH values of galena and sphalerite range from −0.07‰ to 0.03‰ and −0.68‰ to −0.12‰, respectively; and their <em>δ</em>^114/110Cd_{NIST SRM 3108} values vary from −0.96‰ to 3.83‰ and −0.63‰ to 0.77‰, respectively. Our study suggests that the Xiaohongshilazi Pb-Zn-(Ag) deposit should be classified as a Mississippi Valley Type (MVT)-like deposit, because both its geological, sulfide trace elemental, and S-Pb-Fe-Zn-Cd isotopic characteristics are similar to those of the typical MVT deposit, except for the differences of the wall rocks. Rayleigh fractionation during sphalerite precipitation is identified as the primary mechanism for Zn-Cd isotopic variations, which is validated by the Zn-Cd fractionation models from 100 °C to 250 °C. Finally, we propose an ore prospecting model based on migration pathways of ore-forming fluid and the Zn isotopic fractionation model of sphalerite under 100 °C. This model indicates potential resources undiscovered at shallow/peripheral and deep zones of current mining level in both the Eastern and Western Ore Block, with parts of the potential resources having been corroborated by recent drilling. Despite the complexity of mineralization, processes, this study provides new insights into the application of Zn-Cd isotopes in understanding ore genesis and guiding mineral exploration in similar contexts.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 4","pages":"Article 102054"},"PeriodicalIF":8.5,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143882621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"How digitalization, renewable energy, and natural resources shape environmental excellence? Evidence from China using a Quantile-on-Quantile framework","authors":"Wei Chen ,&nbsp;Muhammad Usman ,&nbsp;Rakhshanda Kousar ,&nbsp;Paiman Ahmad","doi":"10.1016/j.gsf.2025.102055","DOIUrl":"10.1016/j.gsf.2025.102055","url":null,"abstract":"<div><div>Natural resources, green energy, and sustainable development are closely linked with concepts that carry mutual goals to endorse social equity, economic prosperity, and ecological stability while curtailing the harmful influence on the globe. However, the recognition of the Sustainable Development Goals (SDG-7, SDG-13) is closely entangled with digital economy. In this pursuit, this study scrutinizes the effect of digitalization, renewable energy, and natural resources on the ecological footprint in China from 1990Q1-2022Q4. The empirical analyses are carried out by employing the Quantile-on-Quantile regression, and cross-quantile and partial cross-quantile correlation approaches to inspect the tail dependence of model parameters. The empirical outcomes highlight how China’s environmental quality is influenced by exogenous variables, including digitalization index, renewable energy consumption, and natural resources. Digitalization has adverse impact on the ecological footprint in lower quantiles, while insignificant in higher quantiles. Moreover, a strong adverse association exists between ecological footprint and renewable energy, which syndicate all the quantiles of renewable energy with linking over lower to middle quantiles and weak in higher quantiles of ecological footprint. Besides, the estimated analysis discloses nuanced dependencies across various quantiles. Similarly, it can be found that the strong negative effect of natural resources on ecological footprint in initial quantiles, moderate in middle quantiles, and less positive effect in higher quantiles. By explaining these dynamics, the current study offers valuable intuitions designed at controlling China toward its dual-carbon target and encouraging the development of a sustainable digital and green economy and thereby, continuing towards achieving SDG-7, and SDG-13 objectives.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 4","pages":"Article 102055"},"PeriodicalIF":8.5,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The future of carbon capture: Basalt’s role in low-hydration CO2 sequestration","authors":"Guoyan Li ,&nbsp;Ranjith P. Gamage ,&nbsp;Yong Liu","doi":"10.1016/j.gsf.2025.102056","DOIUrl":"10.1016/j.gsf.2025.102056","url":null,"abstract":"<div><div>Mitigating climate change demands innovative solutions, and carbon sequestration technologies are at the forefront. Among these, basalt, a mafic volcanic rock packed with calcium, magnesium, and iron, emerges as a powerful candidate for carbon dioxide (CO₂) sequestration through mineral carbonation. This method transforms CO₂ into stable carbonate minerals, ensuring a permanent and environmentally safe storage solution. While extensive research has explored into basalt’s potential under high hydration conditions, the untapped promise of low water content scenarios remains largely unexplored. Our ground-breaking study investigates the mineral carbonation of basalt powder under low water conditions using supercritical CO₂ (sc-CO₂). Conducted at 50 °C and 15 MPa with a controlled moisture content of 30%, our experiment spans various time points (0, 7, 14, 21, and 28 days). Utilising advanced X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), we unveil the mineralogical and morphological transformations. The results are striking: even under low water conditions, basalt efficiently forms valuable carbonate minerals such as calcite, siderite, magnesite, and ankerite. The carbonation efficiency evolves over time, reflecting the dynamic transformation of the basalt matrix. These findings offer pivotal insights into optimising CO₂ sequestration in basalt under low hydration, marking a significant leap toward sustainable carbon capture and storage.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 4","pages":"Article 102056"},"PeriodicalIF":8.5,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143932035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Formation of the rare Xiaoqinling Au-Mo province: Timings and geodynamic triggers","authors":"Panfei Sun ,&nbsp;Zhao Liu ,&nbsp;Lin Yang ,&nbsp;Qingfei Wang ,&nbsp;David I. Groves ,&nbsp;Chao Li ,&nbsp;Huajian Li ,&nbsp;Chaoyi Dong ,&nbsp;Zhiqiang Xue ,&nbsp;Zhongming Li ,&nbsp;Jun Deng","doi":"10.1016/j.gsf.2025.102052","DOIUrl":"10.1016/j.gsf.2025.102052","url":null,"abstract":"<div><div>The timings and geodynamic controls of Mo, Au, and Au-Mo deposits in the Xiaoqinling Orogen (&gt; 630 t Au and 115, 000 t Mo), a rare Au-Mo province globally, are addressed by a combination of mineral parageneses, crystalline mineralogy, geochemistry, and Re-Os and U-Pb geochronology in the Dahu, Qinnan, and Yangzhaiyu deposits. The Xiaoqinling Orogen comprises an E-W-trending fold and thrust system with repeated structural reactivation and the Mo or Au orebodies in these deposits are dominantly controlled by E–W-trending and NW–SE-trending shear zones. Molybdenum mineralization related to K-feldspar alteration comprises early molybdenite, pyrite, rutile, and monazite within gray quartz veins plus late molybdenite and pyrite within white quartz veins in the Dahu and Qinnan Au-Mo deposits. Early and late Au mineralization events have similar mineral assemblages of pyrite, native gold ± Au-Ag-Te minerals, rutile, and monazite associated with quartz-sericite alteration at Yangzhaiyu. The early disseminated molybdenite is characterized by rhombohedral polytype and oscillatory Re zoning, in contrast to the late molybdenite with a coexistence of rhombohedral and hexagonal polytypes and irregularly distributed Re. The early molybdenite has a Re-Os isochron age of 222.5 ± 1.3 Ma, compatible with a monazite U-Pb age of 224 ± 6.1 Ma, whereas late molybdenite provides a Re-Os isochron age of 185.0 ± 12 Ma, with the implication that the 3R-polytype molybdenite with oscillatory Re zoning is more suitable for high-precision dating. The early and late Au mineralization have a pyrite Re-Os age of 202.0 ± 5.9 Ma and U-Pb age of 124.0 ± 1.3 Ma, respectively. In accordance with its complex geodynamic setting, geological and geochronological studies record a complicated 100-million-year mineralization history with multiple magmatic-hydrothermal Mo and orogenic Au mineralization events that formed within a structural framework of multiply reactivated shear zones.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 4","pages":"Article 102052"},"PeriodicalIF":8.5,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143876850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stable chromium isotope fractionation during melt percolation: Implications for chromium isotopic heterogeneity in the mantle","authors":"Haibo Ma ,&nbsp;Li-Juan Xu ,&nbsp;Yu-Wen Su ,&nbsp;Chunyang Liu ,&nbsp;Sheng-Ao Liu ,&nbsp;Jia Liu ,&nbsp;Zezhou Wang ,&nbsp;Guochun Zhao","doi":"10.1016/j.gsf.2025.102049","DOIUrl":"10.1016/j.gsf.2025.102049","url":null,"abstract":"<div><div>To investigate the stable chromium (Cr) isotope variations during melt percolation in the mantle, we analyzed the Cr isotopic compositions of fresh ultramafic rocks from the Balmuccia and Baldissero peridotite massifs located in the Italian Alps. These massifs represent fragments of the subcontinental lithospheric mantle. The samples collected included lherzolites, harzburgites, dunites, and pyroxenites. Lherzolites, formed through 5%–15% fractional melting of a primitive mantle source, exhibited <em>δ</em>⁵³Cr values ranging from −0.13‰ ± 0.03‰ to −0.03‰ ± 0.03‰. These values correlated negatively with Al₂O₃ content, suggesting that partial melting induces Cr isotopic fractionation between the melts and residual peridotites. Harzburgites and dunites, influenced by the silicate melt percolation, displayed distinct <em>δ</em>⁵³Cr values. Notably, dunites not spatially associated with the pyroxenite veins exhibited slightly elevated <em>δ</em>⁵³Cr values (−0.05‰ ± 0.03‰ to 0.10‰ ± 0.03‰) relative to lherzolites. This difference likely resulted from pyroxene dissolution and olivine precipitation during melt percolation processes. However, one dunite sample in direct contact with pyroxenite veins showed lower <em>δ</em>⁵³Cr values (−0.26‰ ± 0.03‰), possibly owing to the kinetic effects during silicate melt percolation. Pyroxenites are formed through the interaction of basaltic melts with the surrounding peridotite via a metasomatic reaction or crystallization in a vein. Most of their <em>δ</em>⁵³Cr values (−0.26‰ ± 0.03‰ to −0.13‰ ± 0.03‰) are positively correlated with MgO contents, suggesting that they were influenced by magmatic differentiation. However, two subsamples from a single clinopyroxenite vein exhibit anomalously low <em>δ</em>⁵³Cr values (−0.30‰ ± 0.03‰ and −0.43‰ ± 0.03‰), which are attributed to kinetic isotopic fractionation during melt-percolation processes. Our findings suggest that melt percolation processes in the mantle contribute to the Cr isotopic heterogeneity observed within the Earth’s mantle.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 4","pages":"Article 102049"},"PeriodicalIF":8.5,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143870241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}