Collaborative Research: RUI: Fe-Mg Interdiffusion in Orthopyroxene and Olivine: A Study Using Rutherford Backscattering to Measure Fe-Mg Diffusion Coefficients at 600-900 Degrees C

合作研究：RUI：斜方辉石和橄榄石中的铁-镁相互扩散：利用卢瑟福背向散射测量 600-900 摄氏度下铁-镁扩散系数的研究

• 批准号: 0229552
• 负责人: John Brady
• 金额: $ 7.16万
• 依托单位: Smith College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-01-01 至 2006-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0229552&HistoricalAwards=false
• 关键词: Collaborative; Research; RUI; Fe; Mg

BradyEAR-0229552Chemical zoning of minerals in terms of their Fe/(Fe+Mg) value can be used to constrain the rates and nature of a variety of geological processes, if the rate of Fe-Mg interdiffusion is known for the minerals of interest. The goal of this project is to measure Fe-Mg interdiffusion rates for the common minerals orthopyroxene and olivine as a function of temperature and oxygen fugacity. Rutherford backscattering will be used to measure the Fe/(Fe+Mg) profiles produced in laboratory experiments. This will permit very short (200 nm) compositional profiles to be measured. Because of the comparatively slow rate of diffusion in orthopyroxene, previous attempts to measure Fe-Mg interdiffusion coefficients for orthopyroxene have been unsuccessful. Diffusion in olivine will also be studied because of disagreement among published diffusion data sets for olivine and to extend the range of measurements to lower temperatures (600-900 degrees C).

BradyEAR-0229552如果感兴趣矿物的 Fe-Mg 相互扩散速率已知，则根据 Fe/(Fe+Mg) 值对矿物进行化学分区可用于约束各种地质过程的速率和性质。 该项目的目标是测量常见矿物斜方辉石和橄榄石的铁镁相互扩散速率与温度和氧逸度的函数关系。 卢瑟福背向散射将用于测量实验室实验中产生的 Fe/(Fe+Mg) 分布。 这将允许测量非常短（200 nm）的成分轮廓。 由于斜方辉石中的扩散速率相对较慢，之前测量斜方辉石 Fe-Mg 相互扩散系数的尝试均未成功。 由于已发表的橄榄石扩散数据集之间存在分歧，因此还将研究橄榄石中的扩散，并将测量范围扩大到较低温度（600-900 摄氏度）。