CSEDI Collaborative Research: Influence of Grain-Size Evolution on Global and Regional Mantle Flow and Upper Mantle Seismic Structure

CSEDI合作研究：粒度演化对全球和区域地幔流及上地幔地震结构的影响

• 批准号: 0854673
• 负责人: Mark Behn
• 金额: $ 26.59万
• 依托单位: Woods Hole Oceanographic Institution
• 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: 2009-08-01 至 2013-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0854673&HistoricalAwards=false
• 关键词: CSEDI; Collaborative; Research; Influence; Grain

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5) Although large-scale convection in the Earth?s mantle ultimately controls tectonic deformation at the Earth's surface, the link between deep mantle flow and plate tectonics remains poorly understood. This is because patterns of mantle flow are difficult to constrain from surface observations and are sensitive to variations in the material (or rheologic) properties that control rock deformation within the plate-mantle coupling zone known as the asthenosphere. The goal of this project is to use computer simulations to evaluate how the material properties of the Earth influence the style of mantle convection. This understanding is important because it will help us quantify the tectonic forces that control geologic deformation and its associated seismic hazard, particularly at plate boundaries where most major earthquakes and volcanic eruptions occur. The results of this project will be directly relevant to several NSF-sponsored programs such as Margins, Ridge2000, CSEDI, CIG, and Earthscope and will help fund graduate students at both WHOI and the University of Hawaii. In the Earth?s asthenosphere, mantle rheology depends on a variety of factors including temperature, pressure, water content, deformation mode, and grain-size, all of which depend on the time-dependent evolution of mantle flow. In this project, the investigators will examine the grain-size dependence of mantle rheology by computing grain-size evolution on a micro-scale (cm and smaller) within 3-D mantle flow models on regional (10s to 100s km) and global (100s to 1000s km) scales. They will accomplish this by incorporating laboratory-based models for grain-size evolution into large-scale mantle flow models to investigate the potential importance of feedbacks between grain-size, rock rheology, and flow. The predictions made by these numerical models will be constrained using seismic data (including variations in seismic anisotropy, wave speed, and attenuation) and rock texture analyses from a spectrum of tectonic environments. In doing so, they will improve our understanding of the relationship between mantle flow, surface tectonics, and grain size in the upper mantle.

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。虽然地球的地幔最终控制着地球表面的构造变形，但深部地幔流动和板块构造之间的联系仍然知之甚少。这是因为地幔流动的模式很难从地表观测中得到约束，并且对控制板幔耦合带（称为软流圈）内岩石变形的材料（或流变学）性质的变化很敏感。该项目的目标是使用计算机模拟来评估地球的物质属性如何影响地幔对流的风格。这一理解很重要，因为它将帮助我们量化控制地质变形及其相关地震危险的构造力，特别是在大多数大地震和火山爆发发生的板块边界。这个项目的结果将直接关系到几个NSF赞助的计划，如边缘，山脊2000年，CSEDI，CIG，和地球镜，并将有助于资助研究生在WHOI和夏威夷大学。在地球上？地幔流变学受温度、压力、含水量、变形方式和粒度等多种因素的影响，而这些因素又依赖于地幔流的时变演化。在该项目中，研究人员将通过在区域（10 s至100 s km）和全球（100 s至1000 s km）尺度上的三维地幔流模型内计算微观尺度（cm或更小）上的粒度演化来研究地幔流变学的粒度依赖性。他们将通过将基于实验室的粒度演化模型纳入大规模地幔流模型来实现这一目标，以研究粒度，岩石流变学和流动之间反馈的潜在重要性。这些数值模型所作的预测将受到地震数据（包括地震各向异性、波速和衰减的变化）和来自构造环境谱的岩石结构分析的约束。在这样做的过程中，他们将提高我们对地幔流动，表面构造和上地幔粒度之间关系的理解。