MARGINS Postdoctoral Fellowship: Deciphering the Role of Melt Segregation and Strain Partitioning in Rifting Continents

MARGINS 博士后奖学金：破译熔体分离和应变分配在裂谷大陆中的作用

• 批准号: 0646696
• 负责人: Benjamin Holtzman
• 金额: $ 21.08万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-03-15 至 2010-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0646696&HistoricalAwards=false
• 关键词: MARGINS; Postdoctoral; Fellowship; Deciphering; Role

The PI test the hypothesis that gradients in strain rate lead to gradients in degrees of melt segregation and thus gradients in seismic anisotropy. To do so he will use three approaches: 1) modeling of elastic properties, 2) application of model to data from Gulf of California, and 3) experiments to understand relationship between melt segregation, strain partitioning and effective viscosity.1. The effects of melt on isotropic velocities are fairly well studied, but anisotropic effects are less well understood. Seismic properties will be affected by aligned olivine crystals, oriented melt pockets at the grain scale, and meter-scale melt-rich layers. These effects are incorporated into a cumulative model of elastic properties, written in terms of the degree of melt segregation, in collaboration with J-M. Kendall (Univ. of Bristol) and Y. Takei (Univ. of Tokyo).2. Data from the seismic experiment in the Gulf of California conducted by J. Gaherty (LDEO) will be compared to data from the Gulf of California, to characterize the orientation and degree of melt segregation.3. The relationship between melt segregation, strain partitioning and effective viscosity will be constrained by deformation experiments on partially molten mantle rocks in torsional geometry, which allows for high-quality rheological data. This portion of the study will be performed in collaboration with D. Kohlstedt and a graduate student (Univ. of Minnesota). The potential broader impact of this project will be, primarily, to support the career of a young scientist. There will also be some training of a graduate student (with Kohlstedt) and increased international collaboration (Japan, Takei).

PI 检验了以下假设：应变率梯度导致熔体偏析程度梯度，从而导致地震各向异性梯度。为此，他将使用三种方法：1) 弹性特性建模，2) 将模型应用于加利福尼亚湾的数据，3) 通过实验来了解熔体偏析、应变分配和有效粘度之间的关系。1．熔体对各向同性速度的影响已得到相当深入的研究，但各向异性效应却鲜为人知。地震特性将受到排列的橄榄石晶体、晶粒尺度定向熔体袋和米尺度熔体丰富层的影响。这些效应被纳入弹性特性的累积模型中，该模型是与 J-M 合作以熔体偏析程度编写的。 Kendall（布里斯托大学）和 Y. Takei（东京大学）.2。 J. Gaherty (LDEO) 在加利福尼亚湾进行的地震实验数据将与来自加利福尼亚湾的数据进行比较，以表征熔体偏析的方向和程度。3．熔融偏析、应变分配和有效粘度之间的关系将受到扭转几何中部分熔融地幔岩石变形实验的约束，从而获得高质量的流变数据。 这部分研究将与 D. Kohlstedt 和一名研究生（明尼苏达大学）合作进行。该项目潜在的更广泛影响将主要是支持年轻科学家的职业生涯。 还将对研究生进行一些培训（与 Kohlstedt 一起）并增加国际合作（日本，武井）。