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Discovering mineral behavior in the hidden Earth: Preface 发现隐藏地球中的矿物行为:前言
IF 8.5 1区 地球科学
Geoscience frontiers Pub Date : 2025-01-01 DOI: 10.1016/j.gsf.2024.101964
Youjun Zhang (Guest editor), Xi Liu (Guest editor), Baohua Zhang (Guest editor), Mingqiang Hou (Guest editor), Jung-Fu Lin (Guest editor)
{"title":"Discovering mineral behavior in the hidden Earth: Preface","authors":"Youjun Zhang (Guest editor), Xi Liu (Guest editor), Baohua Zhang (Guest editor), Mingqiang Hou (Guest editor), 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}
引用次数: 0
Stability and physical properties of brucite at high pressures and temperatures: Implication for Earth’s deep water cycle 水镁石在高压和高温下的稳定性和物理性质:对地球深水循环的启示
IF 8.5 1区 地球科学
Geoscience frontiers Pub Date : 2025-01-01 DOI: 10.1016/j.gsf.2024.101940
Ningyu Sun , Xinyang Li , Luo Li , Qingchun Zhang , Yingxin Yu , Zhu Mao , Cijin Zhou , Dongzhou Zhang
{"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><sub>P</sub> and <em>V</em><sub>S</sub> 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}
引用次数: 0
The Hugoniot curve and sound velocity of forsterite to 1200 GPa 1200 GPa 条件下绿泥石的休格诺曲线和声速
IF 8.5 1区 地球科学
Geoscience frontiers Pub Date : 2025-01-01 DOI: 10.1016/j.gsf.2024.101917
Jian Song , Liang Sun , Huan Zhang , Xiaoxi Duan , Zanyang Guan , Lu Zhang , Xiaokang Feng , Weiming Yang , Hao Liu , Mengsheng Yang , Yulong Li , Dong Yang , Zhebin Wang , Jiamin Yang , Wenge Yang , Toshimori Sekine , Youjun Zhang , Zongqing Zhao , Zhongqing Wu
{"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 (Mg<sub>2</sub>SiO<sub>4</sub>), 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}
引用次数: 0
Constraints on the spin-state transition of siderite from laboratory-based Raman spectroscopy and electrical conductivity under high temperature and high pressure 从实验室拉曼光谱和高温高压下的导电性看菱铁矿自旋态转变的制约因素
IF 8.5 1区 地球科学
Geoscience frontiers Pub Date : 2025-01-01 DOI: 10.1016/j.gsf.2024.101918
Xinyu Zhang , Lidong Dai , Haiying Hu , Meiling Hong , Chuang Li
{"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><sub>4</sub>′ and <em>v</em><sub>1</sub>′), the disappearance of Raman peaks (<em>T</em>, <em>L</em> and <em>v</em><sub>4</sub>) and the discontinuity in the pressure-dependent electrical conductivity can provide robust evidence of electronic spin transitions of Fe<sup>2+</sup> 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><sub>1</sub> (GPa) = 39.318 + 0.015 <em>T</em> (K) and <em>P</em><sub>2</sub> (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}
引用次数: 0
Elasticity of epidote at high pressure and its implications for the velocity anomaly in subduction zone 绿帘石高压弹性及其对俯冲带速度异常的指示意义
IF 8.5 1区 地球科学
Geoscience frontiers Pub Date : 2025-01-01 DOI: 10.1016/j.gsf.2024.101933
Junsheng Ma, Nao Cai, Duojun Wang
{"title":"Elasticity of epidote at high pressure and its implications for the velocity anomaly in subduction zone","authors":"Junsheng Ma,&nbsp;Nao Cai,&nbsp;Duojun Wang","doi":"10.1016/j.gsf.2024.101933","DOIUrl":"10.1016/j.gsf.2024.101933","url":null,"abstract":"<div><div>Hydrous minerals play a critical role in modifying the physical and chemical properties of the Earth’s interior. Among those, epidote is an important hydrous mineral in greenschist and blueschist phases of the metamorphosed subducting crust at shallow depth (30-60 km). Here, we measured the compressional (<em>P</em>) and shear (<em>S</em>) wave velocities of a polycrystalline epidote sample at pressures up to 7 GPa and room temperature by means of ultrasonic interferometry. The obtained sound velocities and elastic moduli of epidote increase monotonically with pressure. Finite strain analysis on those data set yielded the elastic moduli and their pressure derivatives of epidote at ambient condition as follows: <span><math><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>S</mi><mn>0</mn></mrow></msub><mo>=</mo><mn>115.2</mn><mspace></mspace><mi>GPa</mi></mrow></math></span>, <span><math><mrow><msub><mrow><mi>G</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>=</mo><mn>66.7</mn><mspace></mspace><mi>GPa</mi></mrow></math></span>, <span><math><mrow><msubsup><mi>K</mi><mrow><mi>s</mi></mrow><mo>′</mo></msubsup><mo>=</mo><mn>4.6</mn></mrow></math></span>, <span><math><mrow><msup><mrow><mi>G</mi></mrow><mo>′</mo></msup><mo>=</mo><mn>1.1</mn></mrow></math></span>. Using the elastic properties of epidote, we set up a model to better understand the velocity jumps in the subducted oceanic crusts concerning the blueschist-eclogite transition at 60-90 km depths. Our results indicate that the calculated <em>P</em> and <em>S</em> wave velocity jumps are in good agreement with those seismic observations in the typical subduction zones such as northeastern Japan and southwestern Japan. The eclogitization from epidote bearing blueschist may provide an explanation for the wave velocity anomalies occurred in those regions.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101933"},"PeriodicalIF":8.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143172717","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}
引用次数: 0
The effect of antigorite dehydration on velocity structure and water migration in subduction zones 反橄榄岩脱水对俯冲带速度结构和水迁移的影响
IF 8.5 1区 地球科学
Geoscience frontiers Pub Date : 2025-01-01 DOI: 10.1016/j.gsf.2024.101923
Huan Zeng, Maining Ma, Yongbing Li, Jialei Zhang, Hao Guan, Xiao Li
{"title":"The effect of antigorite dehydration on velocity structure and water migration in subduction zones","authors":"Huan Zeng,&nbsp;Maining Ma,&nbsp;Yongbing Li,&nbsp;Jialei Zhang,&nbsp;Hao Guan,&nbsp;Xiao Li","doi":"10.1016/j.gsf.2024.101923","DOIUrl":"10.1016/j.gsf.2024.101923","url":null,"abstract":"<div><div>The water migration in subduction zones, primarily driven by the phase transition in hydrous minerals, can give rise to hydrated regions with reduced velocity. A fundamental element in comprehending and deciphering these low-velocity zones revolves around acquiring insights into the stability and elasticity of relevant hydrous minerals. As one of the main water carriers in shallow areas, antigorite can dehydrate to form talc, forsterite, and fluid (talc–bearing peridotites) in deep areas of subduction zones, and then the talc thus serves as one of the minerals that can bring water to the deep Earth. Here, the elasticity of talc up to 24 GPa and forsterite up to 12 GPa are calculated by using the first principles method. The result supposes that the talc structure transforming from talc I to talc II is at a pressure between 6 GPa and 8 GPa, impacting the trend of elastic wave velocity in response to pressure. Furthermore, the elastic wave velocity of forsterite can be significantly affected by iron concentration. Meanwhile, a variation velocity model with antigorite consumption and talc content is set up for talc-bearing serpentinized peridotite based on the elastic properties of talc and forsterite in this study, and antigorite in Wang et al. (2022). The results of our model demonstrate a decrease in the low-velocity anomaly in subduction zones, particularly in deep regions or areas with higher initial serpentinization degrees. The results also suggest that the mode of antigorite dehydration can diminish the estimation of water content transported to depths of subduction zones, such as the Mariana Trench and Northern Japan subduction zones. The mode of antigorite dehydration thus provides a useful tool for constraining the composition, seismic velocity structure, and water migration in subduction zones.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101923"},"PeriodicalIF":8.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256634","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}
引用次数: 0
Oxygen fugacity-mediated carbonate reactions with siliceous fluids in shallow subduction zones 浅俯冲带硅质流体介导的富氧碳酸盐反应
IF 8.5 1区 地球科学
Geoscience frontiers Pub Date : 2025-01-01 DOI: 10.1016/j.gsf.2024.101891
Fengxia Sun , Jun Hu , Weibin Gui , Ao Deng , Penghui Sun , Fahui Xiong , Jin Liu
{"title":"Oxygen fugacity-mediated carbonate reactions with siliceous fluids in shallow subduction zones","authors":"Fengxia Sun ,&nbsp;Jun Hu ,&nbsp;Weibin Gui ,&nbsp;Ao Deng ,&nbsp;Penghui Sun ,&nbsp;Fahui Xiong ,&nbsp;Jin Liu","doi":"10.1016/j.gsf.2024.101891","DOIUrl":"10.1016/j.gsf.2024.101891","url":null,"abstract":"<div><div>Sediments are one of the main carbon sinks in subduction zones, with CaCO<sub>3</sub> and SiO<sub>2</sub> being the main components in sediments. Their chemical stability plays a significant role in the form of carbon in the Earth’s mantle. Here we report the reactions of CaCO<sub>3</sub> with SiO<sub>2</sub> in hydrated sediments at 0.8–2.0 GPa, 400–500 ℃ and redox-buffered conditions relevant to shallow subduction zones. Our results show that the reaction CaCO<sub>3</sub> + SiO<sub>2</sub> = CaSiO<sub>3</sub> + C + O<sub>2</sub>(fluid) occurs under CoCoO and IW buffered conditions to generate wollastonite (CaSiO<sub>3</sub>) and carbonaceous material (CM). Moreover, wollastonite is formed by the dissolution-crystallization process, which may be significantly affected by oxygen fugacity, leading to distinct crystallization habits (<span><span>Yui, 1966</span></span>, <span><span>Schott et al., 2012</span></span>). Anhydrous experiments indicate that the reaction proceeds only in the presence of H<sub>2</sub>O within the pressure and temperature (P-T) range of this study. The reaction occurs more rapidly with aragonite-structured than calcite-structured CaCO<sub>3</sub>. Further, the experiment buffered with natural olivine at 1.0 GPa and 400 ℃ proves that the above reaction can occur during serpentinization processes in shallow subduction zones. More importantly, nanoscale CM may be generated under relatively reducing conditions, exhibiting Raman characteristics of kerogen. These results provide new insights into how deep carbon is distributed in the Earth’s interior.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101891"},"PeriodicalIF":8.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141692311","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}
引用次数: 0
Stabilizing inverse ringwoodite with defects, and a possible origin for the 560-km seismic discontinuity 有缺陷的稳定逆环纹石,以及 560 千米地震不连续性的可能起源
IF 8.5 1区 地球科学
Geoscience frontiers Pub Date : 2025-01-01 DOI: 10.1016/j.gsf.2024.101896
Xuwei Zhao , Joshua M.R. Muir , Mingda Lv , Zhigang Zhang , Xinjian Bao , Xi Liu
{"title":"Stabilizing inverse ringwoodite with defects, and a possible origin for the 560-km seismic discontinuity","authors":"Xuwei Zhao ,&nbsp;Joshua M.R. Muir ,&nbsp;Mingda Lv ,&nbsp;Zhigang Zhang ,&nbsp;Xinjian Bao ,&nbsp;Xi Liu","doi":"10.1016/j.gsf.2024.101896","DOIUrl":"10.1016/j.gsf.2024.101896","url":null,"abstract":"<div><div>Ringwoodite is an important mineral in the mantle transition zone, and its cationic disorder can profoundly affect its physicochemical properties, but there is currently much controversy about this disorder. In this study, we investigate the cation disorder states of pure Mg<sub>2</sub>SiO<sub>4</sub>-ringwoodite and defective ringwoodite under mantle transition zone conditions through DFT calculations and thermodynamic models. Two stable endmembers are seen, one with normal ringwoodite structure and the other with inverted structure (its Si atoms and half of its Mg atoms have swapped sites). Our results indicate that pure ringwoodite does not invert (swap Mg and Si cations) under normal mantle temperatures but the introduction of a Si-excess, Mg-deficient defect induces a swap at normal mantle temperatures and this swap is likely induced by a wide range of defects including water. Thus, in the presence of such a defect or similar defects the olivine phase transition sequence may then go from olivine to wadsleyite to inverse ringwoodite, and then normal ringwoodite. We calculate the seismic properties of normal and inverse ringwoodite and find significantly slower wave speeds in inverted ringwoodite. Due to this difference the presence of inverse ringwoodite may provide a potential explanation for the discontinuous interface of seismic waves at the depth of ∼560 km.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101896"},"PeriodicalIF":8.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141848931","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}
引用次数: 0
Compressional and shear wave velocities of Fe-bearing silicate post-perovskite in Earth’s lowermost mantle 地球最底层地幔中含铁硅酸盐后透辉石的压缩波和剪切波速度
IF 8.5 1区 地球科学
Geoscience frontiers Pub Date : 2025-01-01 DOI: 10.1016/j.gsf.2024.101915
Jing Yang , Suyu Fu , Jin Liu , Jung-Fu Lin
{"title":"Compressional and shear wave velocities of Fe-bearing silicate post-perovskite in Earth’s lowermost mantle","authors":"Jing Yang ,&nbsp;Suyu Fu ,&nbsp;Jin Liu ,&nbsp;Jung-Fu Lin","doi":"10.1016/j.gsf.2024.101915","DOIUrl":"10.1016/j.gsf.2024.101915","url":null,"abstract":"<div><div>The bridgmanite (Bgm) to silicate post-perovskite (PPv) phase transition is believed to be the main cause for the distinct seismic features observed in the D'' layer, the lowermost region of the Earth’s mantle. However, the transition depth and elasticity of the PPv phase have been highly debated, as the chemical complexity within the D'' layer can largely affect the Bgm-PPv transition pressure and the associated velocity contrast. Experimental measurements of sound velocities for PPv with different chemical compositions under relevant lowermost-mantle conditions are essential but remain limited. In this study, we have reliably measured both compressional wave velocity (<em>V<sub>P</sub></em>), shear wave velocity (<em>V<sub>S</sub></em>), and density, for two Fe-bearing PPv compositions [(Mg<sub>0.85</sub>Fe<sub>0.15</sub>)SiO<sub>3</sub> and (Mg<sub>0.75</sub>Fe<sub>0.25</sub>)SiO<sub>3</sub>] at lowermost mantle pressures using Impulsive Stimulated Light Scattering (ISS), Brillouin Light Scattering (BLS), and X-ray Diffraction (XRD) in diamond anvil cells. Our results indicate that the velocities of Fe-bearing PPv at 120 GPa can be described by the following relationships: <em>V<sub>S</sub></em> (km/s) = 7.65–2.8<em>X<sub>Fe</sub></em> and <em>V<sub>P</sub></em> (km/s) = 14.11–3.8<em>X<sub>Fe</sub></em>, where <em>X<sub>Fe</sub></em> represents mole fraction of the Fe content. The variations in the Fe content of PPv may provide one of the explanations for the seismic lateral variations observed at the Earth’s core mantle boundary. By comparing our results with the high-pressure velocities of Bgm, our velocity model suggests significant discontinuities across the Bgm-PPv transition, characterized by a reduction in both <em>V<sub>P</sub></em> and <em>V<sub>Φ</sub></em>, and an increase in <em>V<sub>S</sub></em>. These findings highlight the importance of considering the influence of chemical composition, particularly Fe content which could vary significantly at the D'' region, on the seismic properties of the PPv phase. The observed velocity contrasts across the Bgm-PPv transition may contribute to the complex seismic signatures observed in the D'' layer, underscoring the potential role of this phase transition in interpreting the seismic features of the lowermost mantle region.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101915"},"PeriodicalIF":8.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185248","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}
引用次数: 0
A first-principles molecular dynamics study of molecular hydrogen diffusion in Fe-free olivine 无铁橄榄石中分子氢扩散的第一原理分子动力学研究
IF 8.5 1区 地球科学
Geoscience frontiers Pub Date : 2025-01-01 DOI: 10.1016/j.gsf.2024.101926
Haibo Liu , Baohua Zhang , Hongzhan Fei , Lei Liu
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