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Multicomponent Diffusion and Speciation Reactions of Major Melt Components, High Field Strength Elements, and Ligands in Haplogranite Melt

长花岗岩熔体中主要熔体成分、高场强元素和配体的多组分扩散和形态反应

基本信息

批准号：
0124179
负责人：
David London
金额：
$ 33万
依托单位：
University of Oklahoma Norman Campus
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2002
资助国家：
美国
起止时间：
2002-01-01 至 2005-12-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=0124179&HistoricalAwards=false
关键词：
Multicomponent Diffusion Speciation Reactions Major

项目摘要

London & DewersEAR-0124179Three projects will assess or utilize mass transport by diffusion in silicate melts to better understand the properties of granitic liquids. In Project I, we will complete a self-consistent thermodynamic, kinetic, and transport model for the crystallization of water-bearing granite melts under near- and far-from-equilibrium conditions. The mathematical algorithms are now mostly developed, and we have recently completed a large number of experiments that provide constraints on the kinetics of crystallization in the granite system. Project II addresses a simple but intriguing question, namely how do granitic melts become homogeneous by diffusion through the melt (i.e., once eutectic grain-boundary contacts are lost)? Preliminary experiments indicate that rapid diffusion of alkalis promotes the attainment of an equilibrium proportion of alkali feldspar components throughout the melt, and that mixing then occurs between this alkali feldspar component and silica derived from the melting of quartz. Project III will address longstanding presumptions about the relationships among ore-forming metals (e.g., Nb, Ta, Sn, W, Zr, Hf, and REE) and potential ligands (halogens F, and Cl, and oxyanions of H, B, P). Not only will the case for speciation be tested, but the stoichiometry of the probable melt species, along with their diffusion coefficients, will be derived. The results of Project III will elucidate the extent to which anions other than oxygen enhance or decrease the solubility of ore-forming metals in melt.

三个项目将评估或利用硅酸盐熔体中扩散的质量传输，以更好地了解花岗岩液体的性质。在项目一中，我们将完成近平衡和远平衡条件下含水花岗岩熔体结晶的自一致热力学、动力学和输运模型。数学算法现在大部分已经发展起来，我们最近完成了大量的实验，为花岗岩系统的结晶动力学提供了约束。项目II解决了一个简单但有趣的问题，即花岗岩熔体如何通过熔体的扩散变得均匀（即，一旦共晶晶界接触丢失）？初步实验表明，碱的快速扩散促进碱长石组分在整个熔体中达到平衡比例，然后在碱长石组分与石英熔融产生的二氧化硅之间发生混合。项目III将解决长期存在的关于成矿金属（如Nb、Ta、Sn、W、Zr、Hf和REE）与潜在配体（卤素F、Cl和H、B、P的氧离子）之间关系的假设。不仅物种形成的情况将被检验，而且可能的熔体物种的化学计量，连同它们的扩散系数，将被推导出来。第三项目的结果将阐明除氧以外的阴离子在多大程度上增强或降低成矿金属在熔体中的溶解度。