Experimental investigation into the thermodynamic properties of halogens

卤素热力学性质的实验研究

基本信息

批准号：
1941721
负责人：
金额：
--
依托单位：
University of Oxford
依托单位国家：
英国
项目类别：
Studentship
财政年份：
2017
资助国家：
英国
起止时间：
2017 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=studentship-1941721
关键词：
Experimental investigation into thermodynamic properties

项目摘要

Recent research has shown that the Earth accreted and differentiated over 30-40 Myr,ecoming more oxidised through time. Stable continental crust was then established relatively quickly. These processes led to the segregation of siderophile (iron-loving) elements to the Earths core and incompatible lithophile (rock-loving) elements to the crust. One of the most intriguing questions facing planetary science is whether the processes experienced by the growing Earth represent those which took place on other terrestrial planets or even exoplanets. The answer lies with Earths nearest neighbour: Mars.The Mars Exploration Rovers (MER) and orbital missions continue to deliver largevolumes of high-quality chemical and mineralogical data from the Martian surface, including bountiful measurements of halogens, including chlorine and bromine. In addition,the Mars Odyssey Gamma Ray Spectrometer (GRS) has mapped the equatorial and midlatitude distribution of elemental Cl abundances at the near-surface of Mars (Zhao and McLennan, 2012). These datasets show the upper few tens of centimetres of Mars is significantly enriched in Cl relative to Martian meteorites and estimates for the bulk composition of the planet. However, it is not homogenously distributed.Much of the focus on the Cl-rich mineralogy of Mars derives from studies of the nakhlite and chassignite meteorites, each containing a broad array of magmatic volatile bearing minerals including Cl-enrichment (Filiberto and Treiman 2009; Filberto, et al., 2014). According to McCubbin et al., (2009), there is a clear link between chlorine-rich hydrothermal uids and magmatic activity in Chassigny and MIL 03346, but it is presently unclear whether the Cl-rich uid was exogenous or endogenous to the magmatic system. M'dard and Grove (2008), found that on a molar basis, Cl is twice as effective as H2O in depressing the liquidus of basalts. Although this does suggest that the addition of Cl to the Martian mantle may lower the magma genesis temperature and potentially aid in the petrogenesis of Martian magmas, current experiments have only explored a basalt composition with a xed Cl concentration; hence, applying their results to the range of Cl concentrations in terrestrial and Martian magmas becomes problematic. Other experiments evaluate the intrinsic effects of dissolved chlorine on Fe3+/PFe and magnetite solubility in hydrous chloride-rich rhyodacitic liquids, and show Cl addition to the melt has two prominent effects on iron: (1) dissolved Cl perturbs the magnetite-melt equilibrium, such that greater FeO total contents are required to support magnetite saturation in Cl-bearing melts than in Cl-free melts of equivalent bulk compositions; and (2) a systematic and progressive decrease of the measured Fe3+/PFe as fO2 is increased. Hence, the two intimately related effects each have important implications for redox processes occurring in Cl-enriched arc magmas. It is, however, well established that the Martian planet is vastly more Fe-rich than rhyodacitic melts. Therefore, bulk composition with lower Al2O3 and higher FeO contents should be tested to further constrain its effect on the influence of chlorine on near-liquidus crystallisation.The solubility of Cl has only been investigated for felsic magmas as above, with few experiments on Martian magmas compositions, which differ significantly from terrestrial. Therefore, the effect of Martian enriched FeO magmas on the solubility of halogens such as Cl is poorly understood. As it is unknown what in infuences Cl solubility, deciphering the partitioning behaviours of the martian mantle will be key to understanding the magmatic activity on Mars.I therefore propose to study Cl solubility within the Martian mantle through experimental methodology, creating chemically similar compositions to assess, if, and the extent at which Fe influences solubility, as this will shed light on the Martia magmatism and evolution.

最近的研究表明，地球会积聚和区分30-40的MYR，随着时间的流逝而氧化更多。然后，稳定的大陆地壳被相对迅速地建立。这些过程导致铁粒（爱心铁）元素隔离到地球核心，而不兼容的岩性（爱好岩石）元素与地壳的元素。行星科学面临的最有趣的问题之一是，不断发展的地球所经历的过程是否代表了在其他陆地行星甚至系外行星上发生的过程。答案在于地球最近的邻居：火星勘探流浪者（MER）和轨道任务继续从火星表面传递大量的高质量化学和矿物学数据，包括对卤素的大量测量，包括氯和溴氨基。此外，火星奥德赛伽玛射线光谱仪（GRS）绘制了火星近地面上元素Cl丰度的赤道和中纬度分布（Zhao and McLennan，2012）。这些数据集表明，相对于火星陨石而言，火星的上几十厘米显着富集，并且估计了行星的整体组成。然而，它不是同质分布的。对火星富含Cl的矿物质学的重点来自于Nakhlite和Chassignite陨石的研究，每个陨石的研究都包含一系列岩浆波动式挥发性轴承矿物质阵列，包括Cl-Enrichment（Filiman和Treiman 2009; Filberto，et e eT e e e e e an e e e e e e et e e e eferiman）。根据McCubbin等人（2009年）的研究，在底盘和MIL 03346中，富含氯的水热UID与岩浆活性之间存在明确的联系，但是目前尚不清楚富含CL的UID是外源性的还是岩浆系统的外源性的。 M'Dard and Grove（2008）发现，在摩尔的基础上，CL的效果是降低玄武岩液体的两倍。尽管这确实表明在火星地幔中添加CL可能会降低岩浆的起源温度并有助于有助于火星岩浆的石化，但当前的实验仅探索了具有XED CL浓度的玄武岩成分。因此，将其结果应用于陆地和火星岩浆中CL浓度范围的范围。 Other experiments evaluate the intrinsic effects of dissolved chlorine on Fe3+/PFe and magnetite solubility in hydrous chloride-rich rhyodacitic liquids, and show Cl addition to the melt has two prominent effects on iron: (1) dissolved Cl perturbs the magnetite-melt equilibrium, such that greater FeO total contents are required to support magnetite saturation in Cl-bearing melts than in Cl-free melts等效的散装组成；（2）随着FO2的增加，测得的Fe3+/PFE的系统和渐进减少。因此，这两个密切相关的效应对富含Cl含量的弧岩浆中发生的氧化还原过程具有重要意义。但是，人们已经确定的是，火星星球比Rhyodacitic融化更丰富。因此，应测试具有较低Al2O3和较高FEO含量的散装组成，以进一步限制其对氯对近液体结晶影响的影响。CL的溶解度仅在上面研究了Felsic Magmas的溶解度，而对Martian Magmas组成的实验很少，与陆生的实验很少，这与地层面有很大不同。因此，对火星富集岩浆的影响对卤素（例如Cl）的溶解度的影响很差。由于尚不清楚，在融合性Cl溶解度中，解释火星地幔的分配行为将是理解Mars.i上的岩浆活动的关键，因此建议通过实验方法研究中的CL溶解度，通过实验方法，通过化学上相似的组成，以及在这种情况下，以及在此范围内，以及在越野范围内，以及在越野范围内构成了何种程度，以及在此范围内的范围。