Emplacement of Large Crustal Sills and The Mechanics of Magmatic Underplating

大型地壳基台的侵位与岩浆底侵机制

• 批准号: 9980664
• 负责人: Mark Simons
• 金额: $ 8.35万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-02-15 至 2002-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9980664&HistoricalAwards=false
• 关键词: Emplacement; Large; Crustal; Sills; Mechanics

Simons 9980664 Intrusion of large sill-like magma bodies plays a major role in the accretion of the Earth's crust and ultimately in the chemical differentiation of the lithosphere. However, the particular mechanisms that control initiation, emplacement, and termination of horizontal magma sheets are poorly understood. Major outstanding problems include the relative importance of ambient stresses and rock strength anisotropy in governing sill initiation and growth, the relationships between sills, feeder dikes, and magma source regions, the character and extent of inelastic deformation accompanying sill emplacement, and intrusion-induced seismicity. This project aims to develop a detailed quantitative understanding of individual underplating events by solving boundary value problems of solid mechanics that explicitly include realistic variations in the host rock properties, effects of the free surface, and inelastic deformation of the host based on reasonable failure laws. The investigators will gain further insight into the dynamics of sill-like intrusions by performing physical analog experiments in collaboration with the Department of Experimental Tectonophysics of Kiev Institute of Geophysics (Kiev, Ukraine). This work will be directly relevant to interpretations of seismicity in the regions of the inferred contemporaneous sill-like magma bodies. By using satellite radar interferometry (InSAR), surface deformation will be measured in the area of Socorro, New Mexico, where anomalous mid-crustal reflector and geodetic uplift have been interpreted as indicating the presence of magma at depth. The investigators will invert the observed deformation to constrain the geometry of the inferred magma body and the dynamics of magma supply.

Simons 9980664大型岩柱状岩浆体的侵入在地壳的增生和岩石圈的化学分异中起着重要作用。然而，控制水平岩浆席的起始、就位和终止的特殊机制却知之甚少。 主要突出的问题包括环境应力和岩石强度各向异性的相对重要性，在控制岩床的启动和增长，岩床之间的关系，馈线堤防，岩浆源区，非弹性变形的性质和程度，伴随岩床侵位，和入侵引起的地震活动。该项目旨在通过解决固体力学的边界值问题，明确包括宿主岩石特性的实际变化，自由表面的影响，以及基于合理的破坏规律的宿主的非弹性变形，来详细定量地了解个体底侵事件。调查人员将与基辅地球物理研究所（乌克兰基辅）实验构造物理学系合作，通过进行物理模拟实验，进一步深入了解岩坎状侵入体的动力学。这项工作将直接相关的推断同生岩坎状岩浆体的地区的地震活动性的解释。将利用卫星雷达干涉测量法（干涉合成孔径雷达）测量新墨西哥州索科罗地区的地表变形，该地区异常的中地壳反射体和大地隆起被解释为表明深部存在岩浆。研究人员将反演观测到的变形，以限制推断的岩浆体的几何形状和岩浆供应的动力学。