Chemical Diffusion in Multicomponent Anhydrous Silicate Melts

多组分无水硅酸盐熔体中的化学扩散

• 批准号: 8720631
• 负责人: Mark Ghiorso
• 金额: $ 12.93万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-06-01 至 1991-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8720631&HistoricalAwards=false
• 关键词: Chemical; Diffusion; Multicomponent; Anhydrous; Silicate

In this project chemical diffusion will be investigated experimentally in silicate melts of basaltic composition. The flattened and polished ends of capsules containing dissimilar materials will be joined by a Pt sleeve and welded shut during initial heating by a thread of gold wire wrapped around the join at the top and bottom of the sleeve. Diffusion profiles will be determined after quenching the couple by longitudinal sectioning and microprobe "linescan" for all eleven major elements. The data on numerous "linescans" corresponding to various diffusion times and initial concentration profiles will be fitted to an appropriate multicomponent solution of the diffusion equation. The aim of this exercise is to extract the off-diagonal (coupling) terms of the diffusion matrix for basaltic magmas. The calibrated diffusion matrices will be used to resolve certain intriguing aspects of crystal growth in magmatic systems ( such as whether oscillatory zoning is a natural consequence of the coupling of diffusion to the crystal liquid interface and the kinetics of interface growth) and to suggest possible melt "species" predominant in basaltic systems.

在该项目中，将对玄武岩成分的硅酸盐熔体中的化学扩散进行实验研究。含有不同材料的胶囊的扁平和抛光末端将通过铂套管连接，并在初始加热过程中通过缠绕在套管顶部和底部连接处的金丝线焊接关闭。 在对所有十一种主要元素进行纵向切片和微探针“线扫描”淬火后，将确定扩散分布。 对应于各种扩散时间和初始浓度分布的大量“线扫描”的数据将被拟合到扩散方程的适当的多分量解。 本练习的目的是提取玄武岩浆扩散矩阵的非对角（耦合）项。 校准的扩散矩阵将用于解决岩浆系统中晶体生长的某些有趣方面（例如振荡分区是否是扩散与晶液界面和界面生长动力学耦合的自然结果），并建议可能的熔融在玄武岩系统中占主导地位的“物种”。