Mapping Small-Scale Structure Above the Core-Mantle Boundary

绘制核幔边界上方的小尺度结构

• 批准号: 0207751
• 负责人: Michael Wysession
• 金额: $ 30万
• 依托单位: Washington University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0207751&HistoricalAwards=false
• 关键词: Mapping; Small; Scale; Structure; Above

WysessionEAR-0207751 The aim of this project is to advance our understanding of the geophysics of the Core-mantle boundary (CMB) region through examination of small-scale regional variations in shear waves that interact with D", the base of the mantle. Specifically, the investigators will look for direct evidence of the foundations of mantle plumes, chemical boundary layers, and subducted slabs at the CMB with the increased resolution provided by the growing database of broadband array data. The CMB displays complexity and variability unequalled within the sub-lithospheric earth. As a major chemical and thermal boundary layer between the rocky mantle and liquid outer core, the CMB likely plays significant roles in the circulation of mass, as well as the transfer of heat both within and between the mantle and core. The investigators will specifically address the following questions: 1) Do mantle plumes form in D"? 2) Are there laterally discrete chemical boundary layers within D"? 3) Do slabs reach the CMB? One-dimensional models of D" structure will be generated using reflectivity synthetics, but final models will also be tested with fully 3D synthetics using the spectral-element method of Komatitsch and Tromp (2001), which has been installed on Washington University's SGI parallel processing machine.

该项目的目的是通过检查与地幔底部D”相互作用的剪切波的小尺度区域变化来促进我们对核幔边界（CMB）区域的地球物理学的理解。 具体来说，研究人员将寻找地幔柱、化学边界层和CMB俯冲板块基础的直接证据，并通过不断增长的宽带阵列数据库提供更高的分辨率。 宇宙微波背景带显示出岩石圈下地球中无与伦比的复杂性和多变性。 作为岩石地幔和液态外核之间的主要化学和热边界层，CMB可能在物质循环以及地幔和核内部和之间的热量传递中起着重要作用。 研究人员将具体解决以下问题：1）地幔柱在D”中形成吗？2)D”内是否存在横向离散的化学边界层？3)板坯是否到达CMB？ D”结构的一维模型将使用反射率合成物生成，但最终模型也将使用Komatitsch和Tromp（2001）的光谱元素方法用全三维合成物进行测试，该方法已安装在华盛顿大学的SGI并行处理机上。