在这里,我们提供了一个潜在的LLSVP组合物的基础上改进的矿物模型,包括,例如,氧化铝的影响重新评估。我们还系统地研究了六个参数的影响:FeO和Al $_{2}$ O $_{3}$含量,比例的CaSiO $_{3}$和bridgmanite(使铁方镁石的比例隐含调查),Fe $^{3+}$ / $\sum$ Fe和温度之间的差异远场地幔和LLSVP。在研究的8100万个案例中,只有79000个案例解释了地震观测。然而,这些成功的情况涉及大范围的参数,例如,FeO含量在12- 25重量%之间,Al $_{2}$ O $_{3}$含量在3- 17重量%之间。然后,我们应用主成分分析(PCA),这些情况下,并找到两个强大的结果:(i)铁方镁石的比例应该是低的($<$ 6体积\%);(ii)形成的Fe $^{3+}$轴承bridgmanite比其他含铁相更有利。根据这些结果,我们确定了两个端员组合物,丰富的Bm和CaPv丰富,并讨论了它们的特点。最后,我们讨论了LLSVP形成的不同方案,并建议调查每个方案产生的矿物比例是评估其相关性的最佳方法。例如,原始岩浆海洋的凝固可能产生FeO和Al $_{2}$ O $_{3}$含量与我们的分析所建议的相似。然而,这种水库的矿物比例并没有很好的约束,可能包含更大比例的铁方镁石比我们的研究结果所允许的。
英文摘要:
Here, we provide a reappraisal of potential LLSVPs compositions based on an improved mineralogical model including, for instance, the effects of alumina. We also systematically investigate the effects of six parameters: FeO and Al$_{2}$O$_{3}$ content, proportion of CaSiO$_{3}$ and bridgmanite (so that the proportion of ferropericlase is implicitly investigated), Fe$^{3+}$/$\sum$Fe and temperature contrast between far-field mantle and LLSVPs. From the 81 millions cases studied, only 79000 cases explain the seismic observations. Nevertheless, these successful cases involve a large range of parameters with, for instance, FeO content between 12--25~wt\% and Al$_{2}$O$_{3}$ content between 3--17~wt\%. We then apply a principal component analysis (PCA) to these cases and find two robust results: (i) the proportion of ferropericlase should be low ($<$6vol\%); (ii) the formation of Fe$^{3+}$-bearing bridgmanite is much more favored than other iron-bearing phases. Following these results, we identify two end-member compositions, Bm-rich and CaPv-rich, and discuss their characteristics. Finally, we discuss different scenarios for the formation of LLSVPs and propose that investigating the mineral proportion produced by each scenario is the best way to evaluate their relevance. For instance, the solidification of a primitive magma ocean may produce FeO and Al$_{2}$O$_{3}$ content similar to those suggested by our analysis. However, the mineral proportion of such reservoirs is not well-constrained and may contain a larger proportion of ferropericlase than what is allowed by our results.
Elasticity of polycrystalline davemaoite constrains its grain size in the lower mantle
State Key Laboratory of Geological Processes and Mineral Resources, School of Earth and Planetary Sciences, China University of Geosciences(中国地质大学地球与行星科学学院);Bayerisches Geoinstitut, Universität Bayreuth(拜罗伊特大学);Earth and Environmental Sciences, University of Michigan(密歇根大学)
Comment on "Mineral-water reactions in Earth's mantle: Predictions from Born theory and ab initio molecular dynamics" by Fowler et al. 2024 (Geochim. Cosmochim. Acta 372, 111-123)
The tetragonal-cubic transition of davemaoite: Implications for lower mantle seismic anomalies
Hawai'i Institute of Geophysics and Planetology, University of Hawai'i at Manoa(夏威夷大学马诺阿分校地球物理与行星学研究所);Department of Earth and Planetary Sciences, Institute of Science Tokyo(东京科学大学地球与行星科学系);SPring-8, Japan Synchrotron Radiation Research Institute(日本同步辐射研究机构 SPring-8);National Synchrotron Light Source II, Brookhaven National Laboratory(布鲁克海文国家实验室国家同步光源二号);Center for Advanced Radiation Sources, The University of Chicago(芝加哥大学先进辐射源中心)
LitCurate: A Configuration-Driven AI-Assisted Framework for Scientific Database Construction with an Application to Lower-Mantle Equation-of-State Data
Iron spin crossover in ferropericlase and its effect on lower-mantle thermal conductivity
Carnegie Institution for Science(卡内基科学机构);Florida International University(佛罗里达国际大学);University of Münster(明斯特大学);The University of Texas at Austin(德克萨斯大学奥斯汀分校);The University of Edinburgh(爱丁堡大学);Deutsches Elektronen-Synchrotron (DESY)(德国电子同步辐射研究所);Albert-Ludwigs Universität Freiburg(弗赖堡大学);European XFEL(欧洲X射线自由电子激光设施);Univ. Lille, CNRS, INRAE, Centrale Lille(里尔大学);Sorbonne Université, Muséum National d’Histoire Naturelle(索邦大学,法国国家自然历史博物馆);Helmholtz-Zentrum Dresden-Rossendorf(德累斯顿-罗斯多夫亥姆霍兹中心);Université Grenoble Alpes(格勒诺布尔阿尔卑斯大学)
Constraints on the production of phosphine by Venusian volcanoes
关于金星云层中存在磷化氢的最初报道,使人们认为火山活动是磷化氢的来源,通过火山喷发的磷化物喷射到云层中。在这里,我们研究的想法,地幔柱火山活动,从地幔深处的物质到表面,可以产生观察到的数量的磷化氢通过相互作用的爆炸爆发的磷化物与硫酸云。地幔深部磷化物的直接喷发是非物理的,但较浅的物质可能含有磷化物的痕迹,并可能喷发到地表。有效地将物质输送到云层的爆炸性喷发需要海洋:岩浆相互作用或水合海洋地壳的俯冲,这两种情况都没有发生在现代金星上。因此,将喷发物质运送到与磷化氢观测值相一致的高度是非常低效的。使用Truong和Lunine提出的模型作为基础案例,我们估计至少需要21,600 km 3/年的喷发量才能解释云中存在1 ppb磷化氢。这比任何历史上的陆地喷发率都要高,并将有几个可检测的后果,需要远程和现场观测来证实。更现实的岩石圈矿物学、火山力学或大气光化学需要更多的火山作用。