Chemical and physical properties of magmatic sulfides and sulfide liquids at conditions of Earth’s deep upper mantle

地球上地幔深处岩浆硫化物和硫化物液体的化学和物理性质

• 批准号: 451014777
• 负责人: Dr. Christopher Beyer
• 金额: --
• 依托单位: Institut für Geologie, Mineralogie und Geophysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/451014777?language=en
• 关键词: Chemical; physical; properties; magmatic; sulfides

Base metal sulfides (Fe-Ni-Cu-S +/- Co, and Zn) and sulfide melts are ubiquitous accessory phases in basalts, peridotites, and mantle xenoliths, and are the most frequent inclusions in diamonds. Due to their nature, they are a sink for highly siderophile elements (HSE) and economically important chalcophile elements like platin-group elements, Cu, Zn, Ag, and Pb. The abundances of HSE in planetary materials are commonly used to track the evolution of planetary reservoirs and core formation, which in conjunction with information of the Re-Os radioactive decay systems, provides us with insights into the chronology of planetary-scale processes. Fe-Ni-Cu-S inclusions are overabundant in diamonds and suggests that a genetic link between sulfides and diamonds exists. We plan to investigate compositions that resemble natural inclusions recovered from lithospheric and sublithospheric diamonds more closely, i.e. compositions with a distinct eclogitic and peridotitic metal to S and Fe to Ni ratio. To complement existing experimental data, carried out at shallow mantle conditions, we will conduct high-pressure/high-temperature experiments at deep mantle conditions (i.e. below 200 km depths to the base of the upper mantle) in equilibrium with different silicates/oxides (olivine, wadsleyite, ringwoodite, majorite, and stishovite) to unravel the conditions of sulfide saturation and their effect on element partitioning between sulfides, sulfide melts, and silicates.Sulfide melts have distinctly different physical properties (e.g. density, viscosity, electrical conductivity) compared to silicates and silicate melts. If sulfide melts develop an interconnected network, which depends on the solid-solid and solid-melt interfacial energies between sulfide melts and coexisting silicates, as well as oxygen and sulfur fugacity, they will significantly contribute to the transport of siderophile and chalcophile elements, as well as the likelihood of efficient metal segregation during planetary core formation. Moreover, sulfide melts can dissolve significant amounts of C and play a key role in the genesis of large diamonds. We will determine the dihedral angle of sulfide melts coexisting with high-pressure mantle phases to identify the conditions under which sulfide melts are mobile in the deep mantle. Moreover, we will address the solubility of C and the precipitation of diamonds from sulfide melts at pressures that represent Earth’s transition zone.

碱金属硫化物（Fe-Ni-Cu-S +/- Co和Zn）和硫化物融化是玄武岩，橄榄岩和地幔异种石的无处不在附属阶段，并且是钻石中最常见的夹杂物。由于它们的性质，它们是高度铁质元素（HSE）和经济上重要的豆科植物（如柏拉丁组元素，Cu，Zn，Ag和Pb）的水槽。行星材料中HSE的丰度通常用于跟踪行星储层和核心形成的演变，这些储层和核心形成结合了重新放射性衰减系统的信息，为我们提供了对行星规模过程年表的见解。 Fe-Ni-Cu-S夹杂物在钻石中过多，表明存在硫化物和钻石之间的遗传联系。我们计划调查类似于从岩石圈和s磷酸钻石中回收的天然夹杂物的组合物，即具有独特的依云母和橄榄岩金属与s和fe ni比的组合物。为了完成在浅层地幔条件下进行的现有实验数据，我们将在深层地幔条件（即低于200公里的深度至上地幔的深度低于200公里的深度）中进行高压/高温实验，并与不同的硅/氧化物/氧化物/氧化物（olivine，olivine，olivine，wadsley，wadsley，wadsley，ringwood，ringwood，ringwood，ringwood，ridever and study sutyers unterfe and unterfe and unterfe and unterfe and unterfe and unterfe and unterfe and unterfe and unterfient and）的影响硫化物，硫化物熔体和硅酮。与有机硅和硅酮相比，硫化物融化具有明显不同的物理特性（例如密度，粘度，电导率）。如果硫化物融化发展一个相互连接的网络，该网络取决于硫化物熔体和共存的硅树脂以及氧气和硫磺的固体熔融和固体融化的界面能量，它们将在促进元素和构造元素方面的多样化元素的运输，并有助于促进辅助元素的运输，以及较高的构造。此外，硫化物融化可以溶解大量的C，并在大钻石的起源中起关键作用。我们将确定与高压地幔相共存的硫化物熔体的二面角，以确定硫化物熔体在深幔中流动的条件。此外，我们将解决C的溶解度以及硫化物融化的钻石的精度，这是代表地球过渡区的压力。