Experimental Quantification of 3D Melt Distribution in Partially Molten Rocks

部分熔融岩石中 3D 熔体分布的实验量化

• 批准号: 0753505
• 负责人: Wen-Lu Zhu
• 金额: --
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-06 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0753505&HistoricalAwards=false
• 关键词: Experimental; Quantification; 3D; Melt; Distribution

Intellectual Merit: This proposal describes an experimental study of melt distribution in partially molten mantle peridotite that will enhance our understanding of the processes of melt generation and transport in the upper mantle beneath oceanic spreading ridges. The 3 main objectives of this project are: 1) to produce texturally equilibrated mono- and polymineralic aggregates containing various amounts of partial melt and to characterize the 3-dimensional (3-D) distribution of melt within these samples and how this changes as a function of melt fraction; 2) to determine the permeability of partially molten rocks based on the experimentally determined 3-D melt distributions; 3) to provide physical constraints on melt migration in partially molten peridotite beneath ocean ridges that will lead to a better understanding of the associated geochemical and geophysical processes. A pilot study indicates that the X-ray synchrotron microtomography will provide valuable 3-D information (such as connectivity) on melt topology, which is a prerequisite for determining the permeability of partially molten rocks. High resolution 2-D SEM microscopy images will be compared to the microtomographic data to assess the fidelity of the latter. Experiments will be carried out at upper mantle conditions using a solid medium piston cylinder device at WHOI. X-ray synchrotron microtomography (Argonne National Laboratory) and Scanning Electron Microscopy (SEM) will be used to quantify melt distribution. Network modeling and the Lattice Boltzmann method will be used to model 3-D complex flow and to provide a quantitative link between the macroscale transport properties and microscale melt distribtution. Incorporation of experimental melt distribution data into the models will facilitate simulation of melt transport and its effects on physical properties of partially molten peridotite at realistic degrees of melting. Broader Impacts of the Proposed Activity: The proposed study will lead to improved models for understanding fluid flow in a number of different geologic systems. Thus, the data will be of interest to scientists in many disciplines. This work will also establish a collaboration between the mantle petrology community and the synchrotron accelerator community that will lead to analytical and theoretical advances. The proposed study will contribute to the professional development of the P.I.s, who are both junior faculty at WHOI, and provide an education and development opportunity for graduate and undergraduate students. In addition to publishing papers in scientific journals, Gaetani and Zhu will work with local high school students and/or undergraduate students to put our experimental results on the internet in a form that will be accessible to a broader audience. Through these education and outreach activities, the proposed research will not only advance our knowledge in basic science, but also serve as platform for cultivating and training researchers of the future.

知识分子的优点：该提案描述了一项对部分熔融地幔橄榄岩中熔体分布的实验研究，这将增强我们对海洋扩散山脊下面地幔熔体产生和运输过程的理解。该项目的3个主要目标是：1）产生含有各种局部熔体的纹理平衡的单层聚集体，并表征这些样品中熔体的3维（3-D）分布，以及它们如何随熔体分数的函数而变化； 2）基于实验确定的3-D熔体分布来确定部分熔融岩石的渗透性； 3）在海脊下部分熔融橄榄石中的熔融迁移时提供物理限制，这将使人们更好地了解相关的地球化学和地球物理过程。一项试点研究表明，X射线同步加速器微传输学将提供有价值的3-D信息（例如连通性），这是确定部分熔融岩石的渗透性的先决条件。 高分辨率的2-D SEM显微镜图像将与显微图数据进行比较，以评估后者的保真度。实验将使用WHOI的固体中型活塞缸装置在上地幔条件下进行。 X射线同步加速器显微镜图（Argonne National Laboratory）和扫描电子显微镜（SEM）将用于量化熔体分布。网络建模和晶格Boltzmann方法将用于建模3-D复合流，并在MacRoscale Transporties和Microscale Melts熔体分布之间提供定量联系。将实验熔体分布数据纳入模型将有助于模拟熔体转运及其对在现实熔化程度下部分熔融橄榄石的物理特性的影响。拟议活动的更广泛的影响：拟议的研究将导致改进的模型，以了解许多不同地质系统中的流体流动。因此，许多学科的科学家将感兴趣的数据。这项工作还将建立地幔质社区与同步加速器加速器社区之间的合作，这将导致分析和理论进步。拟议的研究将为P.I.S的专业发展做出贡献，他们都是WHOI的初级教师，并为研究生和本科生提供教育和发展机会。除了在科学期刊上发表论文外，Gaetani和Zhu还将与当地的高中生和/或本科生合作，以更广泛的受众可以将我们的实验成果放在互联网上。通过这些教育和宣传活动，拟议的研究不仅将提高我们在基础科学方面的知识，而且还可以作为培养和培训未来研究人员的平台。