Collaborative Research: Experimental Determination of Trace Element Partition Coefficients Between Anorthitic Plagioclase and MORB

合作研究：斜长石与MORB之间微量元素分配系数的实验测定

• 批准号: 0926385
• 负责人: A. Dana Johnston
• 金额: $ 17.8万
• 依托单位: University of Oregon Eugene
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-15 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0926385&HistoricalAwards=false
• 关键词: Collaborative; Research; Experimental; Determination; Trace

This research carries out a set of detailed experiments on high temperature plagioclase crystals at crustal pressures and water contents to allow calibration of numerical models of magmatic processes. The importance of this work is that the zoning patterns of feldspar crystals are similar to tree rings in that the zones are often concentric and record the chemical changes that have occurred over time during the growth of the mineral, in this case recording changes in the composition, temperature, and pressure of magmas in which they grew. As such, these minerals can reveal information on the amount of melting in the mantle, the crystallization of a magma, magma residence times, the interaction of magma bodies with the lower crust, and the amount of mass and heat transfer from the mantle to the crust. In short, how the Earth's heat engine works. At present, it is not clear how elements distribute themselves as a function of temperature, pressure, and composition, including H2O in these minerals. The funded research is designed to examine the zoning of Li, Ba, Sr, Pb, Zr and rare earth elements in anorthite plagioclase at pressures to 0.7 GPa in the presence of 0 to 1.5 weight percent H2O. Experiments have been designed with the specific goal of understanding magmatic processes that create the ocean crust, in particular, that associated with slow and intermediate spreading centers and fracture zones. Data will be incorporated into thermodynamic databases for modeling melt composition and evolution. Broader impacts of the work include graduate student training and building essential datasets that make up the infrastructure for science.

本研究对高温斜长石晶体在地壳压力和含水量下进行了一系列详细的实验，以校准岩浆过程的数值模型。这项工作的重要性在于，长石晶体的环带模式与树木年轮相似，因为这些环带通常是同心的，并记录了矿物生长过程中随时间发生的化学变化，在这种情况下，记录了它们生长的岩浆的成分，温度和压力的变化。因此，这些矿物可以揭示有关地幔熔融量，岩浆结晶，岩浆停留时间，岩浆体与下地壳的相互作用以及从地幔到地壳的质量和热量转移量的信息。简单地说，地球的热力引擎是如何工作的。目前，还不清楚元素是如何作为温度、压力和成分的函数分布的，包括这些矿物中的H2O。该资助的研究旨在研究在0至1.5wt%的H2O存在下，在0.7 GPa的压力下，钙长石斜长石中Li，Ba，Sr，Pb，Zr和稀土元素的分区。设计实验的具体目标是了解创造洋壳的岩浆过程，特别是与缓慢和中间扩张中心和断裂带有关的岩浆过程。数据将被纳入热力学数据库，用于模拟熔体组成和演变。这项工作的更广泛影响包括研究生培训和构建构成科学基础设施的基本数据集。