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Collaborative Research: Using Mineral Physics to Interpret Seismic Anisotropy of the Basin and Range Crust

合作研究：利用矿物物理学解释盆地和岭壳的地震各向异性

基本信息

批准号：
0745588
负责人：
George Zandt
金额：
$ 16.28万
依托单位：
University of Arizona
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2008
资助国家：
美国
起止时间：
2008-03-01 至 2013-02-28
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=0745588&HistoricalAwards=false
关键词：
Collaborative Research Using Mineral Physics

项目摘要

Proposal: 0745588 Collaborative Research: Using Mineral Physics to Interpret Seismic Anisotropy of the Basin and Range CrustThe tectonics-scale purpose of this research is to interpret the anisotropy of the lower crust in the Basin and Range using measurements of the anisotropy of local rocks. Understanding the anisotropy of the lower crust is important to geodynamicists, geodesists, petrologists, structural geologists and seismologists who seek to understand its role in processes as diverse as the rheology of the lithosphere, the generation of magmas, geochemical cycling between the crust and mantle, and the formation and genesis of the entire crust. The broader scale purpose of this research is to improve understanding of the causes of anisotropy of the lower crust in general by using mineral-physics based knowledge about the causes of anisotropy as a predictive tool. Rock samples are being studied from two xenolith pipes and three crustal sections in the Basin and Range. Electron-backscatter diffraction is used to measure orientations of all crystals in representative samples. Single-crystal stiffness data are used to calculate the elasticities of the samples. These elasticities are then combined with rock abundance and structure data collected in the field to yield bulk km-scale elasticities for each of the five study sites. Armed with km-scale elasticities for the five study sites plus elasticities for the constituent lithologies we interpret the anisotropy of the Basin and Range lower crust measured from EarthScope's USArray. For the anisotropy studies, we search for anisotropy signals in the receiver functions from the stations closest to the localities of the field samples. Finally, we use what we learn from the site-specific studies to investigate province-wide anisotropy and its tectonic implications.

建议：0745588合作研究：用矿物物理解释盆地和山脉地壳的地震各向异性这项研究的构造尺度目的是通过测量当地岩石的各向异性来解释盆地和山脉下地壳的各向异性。对于地球动力学家、大地测量学家、岩石学家、构造地质学家和地震学家来说，了解下地壳的各向异性很重要，他们试图了解它在岩石圈的流变性、岩浆的生成、壳幔之间的地球化学循环以及整个地壳的形成和成因等各种过程中所起的作用。这项研究的更大范围的目的是通过使用基于矿物物理的关于各向异性原因的知识作为预测工具来提高对一般下地壳各向异性原因的理解。目前正在对盆地和山脉中的两个捕虏体管道和三个地壳剖面的岩石样品进行研究。电子背散射衍射法用于测量具有代表性的样品中所有晶体的取向。使用单晶刚度数据来计算试件的弹性。然后，将这些弹性与现场收集的岩石丰度和结构数据结合起来，得出五个研究地点中每一个的大量公里级弹性。根据五个研究地点的千米级弹性加上组成岩性的弹性，我们解释了从EarthScope的US阵列测量的盆地和山脉下地壳的各向异性。对于各向异性研究，我们从距离现场样本位置最近的站的接收器函数中搜索各向异性信号。最后，我们利用我们从现场研究中学到的东西来调查全省范围内的各向异性及其构造意义。