Physical Properties of Partially Molten Rocks from Microtomography Experiments and Digital Rock Physics

显微断层摄影实验和数字岩石物理中部分熔融岩石的物理性质

• 批准号: 1551300
• 负责人: Wen-Lu Zhu
• 金额: $ 29.91万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-02-01 至 2020-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1551300&HistoricalAwards=false
• 关键词: Physical; Properties; Partially; Molten; Rocks

Melt generated in the interior of the Earth at plate boundaries plays an important role in the transfer of heat and mass and eventually feeds the volcanic activity of our planet. It is important to better constrain how much melt is present at depth and where it is present. Seismic and electromagnetic measurements provide data to constrain melt distribution but how to convert these data into melt fraction estimates remains a subject of contention. This project will analyze three-dimensional images of the distribution of melt in experimentally produced partially molten rocks and simulate several physical properties of these samples. Results from this study will make it possible to link seismic and electromagnetic data with models of melt transport in the interior of the Earth, which ultimately helps understand how plate tectonics works and the link between mantle processes and volcanic activity.This study will use synchrotron microtomography to image partially molten mantle rocks in three-dimensions. The samples will be hydrostatically-annealed aggregates that consist of olivine and orthopyroxene in different proportions, and contain melt fractions of 0.005 to 0.20. Digital rock physics simulations will be performed to obtain permeability, electrical conductivity and elastic moduli of both hydrostatically annealed olivine + orthopyroxene-basaltic melt and sheared partially molten olivine rocks. Variation of melt content with distance in the sample will be analyzed to constrain the bulk viscosity of the sample. This project will quantify the effects of lithological partitioning due to the presence of orthopyroxene on melt distribution and show how deformation affects melt distribution, and induces permeability anisotropy.

在地球内部板块边界产生的熔体在热量和质量的传递中起着重要作用，并最终为我们星球的火山活动提供了动力。重要的是要更好地限制有多少熔体存在于深度和它存在的位置。地震和电磁测量提供的数据来约束熔体分布，但如何将这些数据转换为熔体分数估计仍然是一个有争议的问题。该项目将分析实验产生的部分熔融岩石中熔体分布的三维图像，并模拟这些样品的几种物理性质。这项研究的结果将使地震和电磁数据与地球内部熔体输送模型联系起来成为可能，这最终有助于了解板块构造如何运作以及地幔过程与火山活动之间的联系，这项研究将使用同步加速器显微层析成像技术对部分熔融的地幔岩石进行三维成像。样品将是由不同比例的橄榄石和斜方辉石组成的流体静力退火聚集体，并含有0.005至0.20的熔体分数。将进行数字岩石物理模拟，以获得流体静力退火橄榄石+斜方辉石玄武岩熔体和剪切部分熔融橄榄石岩石的渗透率，电导率和弹性模量。将分析样品中熔体含量随距离的变化，以限制样品的体积粘度。该项目将量化由于斜方辉石的存在对熔体分布的岩性分区的影响，并显示变形如何影响熔体分布，并诱导渗透率各向异性。

项目成果

Experimental evidence for melt partitioning between olivine and orthopyroxene in partially molten harzburgite: MELT PARTITIONING IN HARZBURGITE

部分熔融方辉橄榄石中橄榄石和斜方辉石熔体分配的实验证据：方辉橄榄石中的熔体分配

• DOI: 10.1002/2016jb013122
• 发表时间: 2016
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: Miller, Kevin J.;Zhu, Wen-lu;Montési, Laurent G.;Gaetani, Glenn A.;Le Roux, Véronique;Xiao, Xianghui
• 通讯作者: Xiao, Xianghui