Geoscience frontiers最新文献

{"title":"Detrital zircons from Cambrian rocks of western Laurentia define two episodes of Rodinian rift-related magmatism","authors":"Lauren I. Madronich ,&nbsp;William A. Matthews ,&nbsp;Thomas Hadlari ,&nbsp;Chad Morgan ,&nbsp;Charles M. Henderson","doi":"10.1016/j.gsf.2025.102007","DOIUrl":"10.1016/j.gsf.2025.102007","url":null,"abstract":"<div><div>Many aspects of the disassembly of Neoproterozoic supercontinent Rodinia remain poorly constrained. Current models for the breakup along western Laurentia (present coordinates) do not fully reconcile stratigraphic observations regarding the timing and mechanisms of continental rifting. Latest Neoproterozoic to Cambrian stratigraphic units exposed along the North American Cordillera from southwestern Canada to the southwestern United States contain Neoproterozoic and Cambrian zircons interpreted to be sourced from rift-related igneous rocks generated during the fragmentation of Rodinia. Two discrete magmatic episodes distinguished by a ca. 50 Myr period of apparent magmatic quiescence are identified using the detrital record: (1) Tonian and Cryogenian to earliest Ediacaran magmatism (mantle plume events followed by rifting); and (2) latest Ediacaran to late Cambrian magmatism. The detrital zircon record of the first episode supports a 660–650 Ma rift-to-drift transition followed by passive margin sedimentation of the upper Windermere Supergroup. After a period of apparent magmatic quiescence from 630–580 Ma, detrital zircon dates of 580–520 Ma from central-western Laurentia provide evidence for renewed rift magmatism preceding the initiation of the lower Paleozoic passive margin. These new U-Pb dates are used to present a refined model of Rodinia disassembly with improved timing constraints suggesting that its final breakup and the Sauk I transgression occurred ca. 520 Ma, in accordance with recent revisions to the timing of the Sauk transgressions in southwestern Laurentia.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 2","pages":"Article 102007"},"PeriodicalIF":8.5,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantifying production rates of tropical granitic regolith in Hainan Island, south China: A multi-stage U-series disequilibrium study","authors":"Guodong Jia ,&nbsp;Xu Yvon Zhang ,&nbsp;François Chabaux ,&nbsp;Eric Pelt ,&nbsp;Zhiqi Zhao ,&nbsp;Sheng Xu ,&nbsp;Congqiang Liu","doi":"10.1016/j.gsf.2025.102002","DOIUrl":"10.1016/j.gsf.2025.102002","url":null,"abstract":"<div><div>Regolith, widely distributed on the Earth’s surface, constitutes a significant compartment of the Critical Zone, resulting from intricate interactions among the atmosphere, lithosphere, hydrosphere, and biosphere. Regolith formation critically influences nutrient release, soil production, and long-term climate regulation. Regolith development is governed by two primary processes: production and denudation. An urgent need exists to comprehensively understand these processes to refine our understanding of Critical Zone functions. This study investigates an in-situ regolith profile developed on granitic bedrock from a tropical region (Sanya, China). We conducted geochemical analyses, encompassing major, trace elements and mineralogical compositions as well as U-series isotopes, and applied the U-series disequilibrium method to investigate the formation history of this profile. Alternatively, dividing the regolith profile into sub-weathering zones provides a better explanation for the geochemical results, and a multi-stage model based on this subdivision effectively interprets the evolution of deep regolith. Utilizing this multi-stage model, regolith production rates is derived from the “gain and loss” model, ranging from 1.27 ± 0.03 to 42.42 ± 24.24 m/Ma. The production rates first increase from surface until a maximum rate is reached at the depth of ∼ 160 cm and then decrease at further deeper horizons along the depth profile, and the variation of production rates follows a so-called “humped function”. This pioneering investigation into regolith production rates in the Chinese tropical region indicates that (1) the studied profile deviates from a steady state compared to the denudation rate derived from cosmogenic nuclides (¹⁰Be_in-situ); (2) subdividing the deep profile based on geochemical data and U-series isotopic activity ratios is imperative for accurately determining regolith production rates; and (3) the combination of U-series disequilibrium and cosmogenic nuclides robustly evaluates the quantitative evolution state of regolith over long time scales.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 3","pages":"Article 102002"},"PeriodicalIF":8.5,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143637627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tectonic setting of the Youjiang giant tin belt, South China: New findings from the Pingna W-Sn deposit","authors":"Changhao Xiao ,&nbsp;Zhengle Chen ,&nbsp;Changshan Wei ,&nbsp;Pingping Yu ,&nbsp;Xiangchong Liu ,&nbsp;Yanwen Tang ,&nbsp;Yu Zhang","doi":"10.1016/j.gsf.2025.102006","DOIUrl":"10.1016/j.gsf.2025.102006","url":null,"abstract":"<div><div>Growing evidence suggests that extensional/transtensional settings are favorable for the formation of tin deposits, yet the underlying geodynamic mechanism remains equivocal. The Pingna W-Sn deposit, found in the underexplored interior of the giant tin belt within the Youjiang Basin, South China, offers a unique opportunity to explore and better constrain the current geodynamic model for tin mineralization. This deposit, composed of NW- to NWN-striking vein swarms with W-Sn mineralization, is hosted in the Middle Triassic clastic rocks without igneous rocks near its mineralization. Structural analysis indicates that the Youjiang fold-and-fault belt and the ore-related structures in the Pingna deposit experienced five deformation phases (D₁–D₅). The pre-ore NE-striking compression (D₁; σ_v = σ₃) initiated fault-fracture meshes, followed by NE-striking extension (D₂), while NW-striking compression (D₃; σ_v = σ₂) enhanced the vertical connectivity of the meshes. Syn-mineralization E-W extension (D₄; σ_v = σ₁) facilitated upward through-going flow and hydrothermal fluids infilled the meshes, forming a fault-vein system. The mineralized veins were cut across by post-ore WNW-striking oblique fault with sinistral and normal components (D₅). The meshes dictated Sn-W orebodies localization. Hydrothermal veins formed in three stages: (I) muscovitization-bordered tin-dominated quartz vein swarms along the Pingna fault; (II) W-dominated lit-par-lit vein system; and (III) barren calcite veins crosscutting the former veins. The Pingna W-Sn mineralization formed during the Late Cretaceous as constrained by the cassiterite (<em>Cst1</em>) U-Pb age of 95.6 ± 2.4 Ma (2σ, MSWD = 1.2), muscovite (<em>Ms1</em>) ⁴⁰Ar-³⁹Ar plateau age of 93.9 ± 0.1 Ma (2σ, MSWD = 1.7), and molybdenite Re-Os age of 92.9 ± 1.2 Ma (2σ, MSWD = 0.3). Outward lateral zoning of the Sn-W mineralization, as well as associated muscovitization and silicification implies the epicenter of hydrothermal fluid is near the No. II vein swarm. Contemporaneous felsic dykes coupling with the inferred intrusions demonstrate that the Pingna deposit is a distal hydrothermal W-Sn deposit. The releasing bend of the NW-striking Pingna fault controlled the distribution of tin-dominated mineralization, while the anticlines controlled the tungsten-dominated mineralization. Our findings suggest that the localization and formation of the Pingna W-Sn veins were controlled by Late-Cretaceous regional transtensional stress field and polyphase deformation, rather than previously proposed local extension of the Youjiang Basin. The discovery of the Pingna W-Sn deposit highlights the interior of the Youjiang Basin as a promising area for tungsten-tin exploration.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 2","pages":"Article 102006"},"PeriodicalIF":8.5,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143357059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Toxic impacts of polystyrene nanoplastics and PCB77 in blunt snout bream: Evidence from tissue morphology, oxidative stress and intestinal microbiome","authors":"Fang Chen ,&nbsp;Zhen Li ,&nbsp;Zeliang Su ,&nbsp;Hongping Liao ,&nbsp;Dandan Gao ,&nbsp;Linyong Zhi ,&nbsp;Chunmiao Kong ,&nbsp;Qingzhi Zheng ,&nbsp;Jun Wang","doi":"10.1016/j.gsf.2025.102005","DOIUrl":"10.1016/j.gsf.2025.102005","url":null,"abstract":"<div><div>Polystyrene nanoplastics (PS-NPs) and 3,3′,4,4′-tetrachlorobiphenyl (PCB77) are common pollutants in freshwater aquatic environments. To investigate the separate and combined toxicity of these two pollutants on the freshwater blunt snout bream (<em>Megalobrama amblycephala</em>), 270 juveniles were randomly assigned to six exposure treatments: the control group, CT (free of PS-NPs and PCB77)<em>,</em> three single exposure groups, PS-L (0.2 mg/L PS-NPs), PS-H (2 mg/L PS-NPs), PCB (0.01 mg/L PCB77), and two combined exposure groups, PP-L (0.2 mg/L PS-NPs + 0.01 mg/L PCB77) and PP-H (2 mg/L PS-NPs + 0.01 mg/L PCB77). After a seven-day exposure, the tissue histopathology, antioxidant capacity, inflammatory response, and gut microbiome composition of fish were analyzed. The results showed that tissue fluorescence intensity of PS-NPs increases as the exposure levels of PS-NPs increase, and the combined exposure groups exhibited higher fluorescence intensity compared to their single PS-NPs exposure groups. Histopathological analysis showed that the exposure groups exhibited varying degrees of damage to the intestinal tissue compared to the control group, with more severe damage observed in the combined exposure groups. Additionally, liver damage was evident in the PS-H, PP-L and PP-H groups. Furthermore, the highest catalase (CAT) activities and malondialdehyde (MDA) contents were found in the intestine and liver of fish in the PP-L and PP-H groups. The mRNA levels of inflammatory factors (<em>il</em>, <em>il-1β</em>, <em>il-8</em>, <em>il-6</em>, <em>il-10</em>, and <em>tnf-α</em>) were up-regulated in the PS-H, PP-L and PP-H groups compared to those of the CT group. In addition, remarkable alternations in the intestinal microbiome compositions were observed among the groups: the abundance of Verrucomicrobiome and Planctomycetota increased in all exposed groups compared to that of the control group, while the abundance of Actinobacteriota was significantly reduced in the exposure groups. Functional prediction of microbiota indicated that the amino acid and carbohydrate metabolism, as well as intestinal structure, were impaired in the PS-NPs and PCB77 exposure groups. The results suggested that the toxicity of PS-NPs on <em>M. amblycephala</em> including tissue injury, oxidative stress, and disturbance of intestinal microbiota, depends not only on concentration but also increases when co-exposed to PCB77. This finding raises concerns about the ecological safety in freshwater aquatic environments.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 2","pages":"Article 102005"},"PeriodicalIF":8.5,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Life cycle analysis of green technologies: Assessing the impact of environmental policies on carbon emissions and energy efficiency","authors":"Khan Baz ,&nbsp;Zhen Zhu","doi":"10.1016/j.gsf.2025.102004","DOIUrl":"10.1016/j.gsf.2025.102004","url":null,"abstract":"<div><div>A growing trend in environmental contamination has highlighted the need for greater access to green technologies and clean energy to alleviate environmental stress. This study seeks to quantify the impact of climate mitigation technologies, particularly those related to environmental technology, on environmental quality and economic development. The relationship between environment-related technologies, disaggregated energy use, carbon dioxide emissions, and the stringency of environmental policies was analyzed using Westerlund co-integration, FGLS, and Granger causality techniques across 19 member countries of the Organization for Economic Co-operation and Development (OECD). The findings show that an increase in fossil fuel use leads to a rise in carbon emissions. Similarly, the use of renewable energy also contributes to higher carbon emissions, while environment-related technologies have a positive impact on environmental quality. In contrast, stricter environmental policies have a negative effect on carbon dioxide emissions. A one-way causality was identified, with environment-related technologies, renewable energy adoption, and environmental policy stringency influencing carbon dioxide emissions, rather than being influenced by them. These findings underscore the significance of environment-related technology in enhancing both environmental quality and economic productivity. Policymakers are encouraged to focus on allocating resources for research, establishing robust regulatory frameworks, fostering collaboration, promoting education and awareness, and providing support for sectors transitioning toward climate change mitigation technologies.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 2","pages":"Article 102004"},"PeriodicalIF":8.5,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Decarbonization of siderite in the water-rich upper mantle","authors":"Mengqi Guo,&nbsp;Fangfei Li,&nbsp;Xinyang Li,&nbsp;Zhaodong Liu,&nbsp;Liang Li,&nbsp;Daoyuan Wu,&nbsp;Qiang Zhou","doi":"10.1016/j.gsf.2024.101930","DOIUrl":"10.1016/j.gsf.2024.101930","url":null,"abstract":"<div><div>The aqueous fluids within subducted slabs have the potential to influence the form of carbonate presence and the carbon cycling process. Experiments were performed on resistive heating diamond anvil cell using siderite crystals and grains with water under conditions of pressure as high as 11.4 GPa and temperatures reaching up to 530 °C. These experiments aimed to simulate geological reactions that may occur within a depth range of 340 km in subducted slabs. Raman spectroscopy was employed to monitor the reactions and microscale phenomena within the sample chamber as pressure and temperature increase. The recovered products were analyzed using scanning electron microscopy and transmission electron microscopy. The results indicate that at 0.8 GPa and 108 °C, a Fischer-Tropsch Type (FTT) reaction occurred on the sample surface, resulting in the formation of organic compound formaldehyde, followed by the observation of formic acid. At higher pressure and temperature (3.5 GPa, 420 °C), the formation of γ-Fe₂O₃ and γ-FeOOH was observed on the sample surface, accompanied by the release of CO₂ and H₂. Transmission electron microscope analysis of the quenched product powders indicated that the generated iron oxides were consistent with the phases observed at high pressure and temperature conditions. High pressure and temperature dissolution experiments of siderite in water reveal that carbon may be released into the mantle wedge entirely in the form of CO₂ in warm subducted slabs and cold subducted slabs that subduct to depths of 75 km. The released CO₂ participates in the carbon cycle of the island arc volcanic systems in the upper mantle at depths of 70–120 km and accelerates the transfer of subducted carbon to the Earth’s surface.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101930"},"PeriodicalIF":8.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143172715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discovering mineral behavior in the hidden Earth: Preface","authors":"Youjun Zhang (Guest editor),&nbsp;Xi Liu (Guest editor),&nbsp;Baohua Zhang (Guest editor),&nbsp;Mingqiang Hou (Guest editor),&nbsp;Jung-Fu Lin (Guest editor)","doi":"10.1016/j.gsf.2024.101964","DOIUrl":"10.1016/j.gsf.2024.101964","url":null,"abstract":"","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101964"},"PeriodicalIF":8.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143171408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stability and physical properties of brucite at high pressures and temperatures: Implication for Earth’s deep water cycle","authors":"Ningyu Sun ,&nbsp;Xinyang Li ,&nbsp;Luo Li ,&nbsp;Qingchun Zhang ,&nbsp;Yingxin Yu ,&nbsp;Zhu Mao ,&nbsp;Cijin Zhou ,&nbsp;Dongzhou Zhang","doi":"10.1016/j.gsf.2024.101940","DOIUrl":"10.1016/j.gsf.2024.101940","url":null,"abstract":"<div><div>Brucite is a common hydrous mineral on Earth and may contribute to the deep water cycle of the Earth, but its stability and structure under mantle conditions remain uncertain. In this study, we investigated the stability of brucite up to 60 GPa at 800 K and 45 GPa at 1850 K. Within the experiment <em>P-T</em> conditions, no theoretically predicted new phase was observed, and brucite remained in the <em>P</em><span><math><mrow><mover><mrow><mn>3</mn></mrow><mrow><mo>¯</mo></mrow></mover></mrow></math></span><em>m</em>1 structure. With the determined thermal EoS of brucite and the elastic parameters of mantle minerals, we modeled the velocity and density profile of subducted hydrous harzburgite in the top lower mantle, assuming that the water was stored in brucite and phase D. Based on the modelling, 1 wt.% water will reduce the velocity and density of harzburgite by ∼ 5% and ∼ 2%, respectively, yet whether the water is stored in brucite or phase D has weak influence on both density and velocity. With a water content up to 2.4 wt.%, the density of hydrous harzburgite could be reduced to 2.2(2)%–2.8(2)% lower than the surrounding mantle, while the <em>V</em>_P and <em>V</em>_S of hydrous harzburgite are still 0.3(1)%–0.7(1)% and 0.7(2)%–1.8(2)% higher than that of the normal mantle. Thus, the low-density hydrous harzburgite may slow down the subducting of slab, despite being a high-velocity body in seismic observations.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101940"},"PeriodicalIF":8.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143172714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Hugoniot curve and sound velocity of forsterite to 1200 GPa","authors":"Jian Song ,&nbsp;Liang Sun ,&nbsp;Huan Zhang ,&nbsp;Xiaoxi Duan ,&nbsp;Zanyang Guan ,&nbsp;Lu Zhang ,&nbsp;Xiaokang Feng ,&nbsp;Weiming Yang ,&nbsp;Hao Liu ,&nbsp;Mengsheng Yang ,&nbsp;Yulong Li ,&nbsp;Dong Yang ,&nbsp;Zhebin Wang ,&nbsp;Jiamin Yang ,&nbsp;Wenge Yang ,&nbsp;Toshimori Sekine ,&nbsp;Youjun Zhang ,&nbsp;Zongqing Zhao ,&nbsp;Zhongqing Wu","doi":"10.1016/j.gsf.2024.101917","DOIUrl":"10.1016/j.gsf.2024.101917","url":null,"abstract":"<div><div>The comprehension of the composition and physical state of the deep interiors of large planets, as well as the impact events pertinent to planetary formation and evolution, necessitates an understanding of the properties of planetary materials under extreme conditions. Forsterite (Mg₂SiO₄), a significant geological mineral, has not been fully characterized in terms of its behavior under shock compression due to a lack of consensus among previous experiments and simulations aimed at determining its Hugoniot, as well as the absence of knowledge of sound velocity at high pressures, a critical parameter indicative of phase transformation and melting.</div><div>In this study, we delineated the Hugoniot curve of the mineral forsterite up to immense pressures of 1200 GPa. For the first time, we successfully constrained its sound velocity along the Hugoniot curve up to 760 GPa by combining laser-driven shock experiments with first-principles molecular dynamics simulations. The measured Hugoniot data for forsterite corroborated previous findings and suggested the occurrence of incongruent melting during shock compression. Remarkably, along their respective Hugoniot curves, the sound velocity of forsterite was observed to fall between that of the minerals bridgmanite and periclase. The remarkable agreement between the experimental results and simulation data provides reliable sound velocity measurements on the forsterite Hugoniot, which is critical for comprehensively understanding the phase transition and melting behavior of forsterite under ultra-high pressures. This knowledge sheds invaluable light on the behavior of this significant geological mineral under extreme conditions akin to those found in the interiors of planets.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101917"},"PeriodicalIF":8.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Constraints on the spin-state transition of siderite from laboratory-based Raman spectroscopy and electrical conductivity under high temperature and high pressure","authors":"Xinyu Zhang ,&nbsp;Lidong Dai ,&nbsp;Haiying Hu ,&nbsp;Meiling Hong ,&nbsp;Chuang Li","doi":"10.1016/j.gsf.2024.101918","DOIUrl":"10.1016/j.gsf.2024.101918","url":null,"abstract":"<div><div>The vibrational and electrical transport properties of natural siderite are systematically investigated by means of <em>in-situ</em> Raman spectroscopy and alternating current impedance spectroscopy under conditions of 0.6–55.6 GPa, 298–873 K and different hydrostatic environments using a diamond anvil cell (DAC). Upon non-hydrostatic compression, all of these observable characteristic variations of siderite including the appearance of three absolutely new Raman peaks (<em>L</em>’, <em>v</em>₄′ and <em>v</em>₁′), the disappearance of Raman peaks (<em>T</em>, <em>L</em> and <em>v</em>₄) and the discontinuity in the pressure-dependent electrical conductivity can provide robust evidence of electronic spin transitions of Fe²⁺ from high-spin to mixed-spin to low-spin states at the respective pressures of 42.5 GPa and 48.5 GPa. As far as hydrostatic condition, the electronic spin states from high-spin to mixed-spin to low-spin states occurred at the higher pressures of 45.7 GPa and 50.4 GPa, respectively, which implied the highly sensitive hydrostaticity of electronic spin transition pressures. Upon decompression, the reverse electronic spin transitions from low-spin to mixed-spin to high-spin states were detected at the respective pressures of 47.2 GPa and 28.7 GPa under non-hydrostatic condition, and as well as at the pressures of 49.4 GPa and 25.1 GPa under hydrostatic condition, respectively. The huge pressure hysteresis of 13.8 GPa and 20.6 GPa for the electronic spin state transition was revealed under non-hydrostatic and hydrostatic environments, respectively. In order to explore the effect of temperature on the electronic spin transition, a series of electrical conductivity experiments on siderite were performed over the temperature range of 323–873 K under conditions of three typical pressures of 47.7, 49.8 and 51.6 GPa. Furthermore, the functional relationships between the temperature and pressure describing the high-spin to mixed-spin to low-spin transitions for siderite were successfully established: <em>P</em>₁ (GPa) = 39.318 + 0.015 <em>T</em> (K) and <em>P</em>₂ (GPa) = 41.277 + 0.018 <em>T</em> (K), respectively. In conclusion, our acquired phase diagram of the electronic spin transition on siderite is beneficial to deep insight into the electronic spin behavior for those of iron-bearing carbonate minerals under high-temperature and high-pressure conditions.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101918"},"PeriodicalIF":8.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}