The Keel of the Amazonian Craton

亚马逊克拉通的龙骨

• 批准号: 0538267
• 负责人: Suzan van der Lee
• 金额: $ 20.32万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0538267&HistoricalAwards=false
• 关键词: Keel; Amazonian; Craton

This project aims to reveal lateral and vertical variations within the lithospheric keel of Precambrian South America through imaging the S-velocity structure of the upper mantle and crust beneath northern South America. This imaging will be based on a combination of seismic data from the BLSP02 network with pre-existing data.The BLSP02 network represents a completed field experiment, which was a joint effort between the University of Sao Paulo and the Swiss Federal Institute of Technology. The BLSP02 experiment gathered seismic data on about fifteen broadband seismometers in the period 2002-2004. The seismometers were placed throughout all of eastern Brazil.Variations within Precambrian keels provide clues to their formation and evolution. Further constraints on their formation and evolution comes from the proposed comparison with the keel of Precambrian North America, which is extensively studied separately and in the past. Imaging such variations is done through seismic tomography. The tomographic method to be applied combines measured surface wave group velocities with regional waveforms, independent estimates of crustal thickness, and arrival times of teleseismic S waves. The combination of these different types of data optimally enhances resolving power for lateral and vertical variations in seismic rigidity within the large region that encompasses Precambrian South America.This research is being jointly funded by the Geophysics program and the Office of International Science and Engineering, which is supporting the collaboration between the US and Brazilian scientists.

该项目旨在通过成像南美洲北部之下上地幔和地壳的S速度结构来揭示南美洲前寒武纪岩石圈龙骨内的横向和垂直变化。这一成像将基于BLSP02网络的地震数据和先前存在的数据的组合。BLSP02网络是圣保罗大学和瑞士联邦理工学院共同努力完成的野外实验。BLSP02实验在2002-2004年间收集了大约15台宽带地震仪的地震数据。地震仪分布在整个巴西东部。前寒武纪龙骨内的变化为它们的形成和演化提供了线索。对它们的形成和演化的进一步限制来自于拟议的与前寒武纪北美龙骨的比较，这是单独和过去广泛研究的。对这种变化的成像是通过地震层析成像完成的。所采用的层析成像方法将测量的面波群速度与区域波形、地壳厚度的独立估计以及远震S波的到达时间相结合。这些不同类型数据的组合优化地提高了南美洲前寒武纪大范围内地震刚性横向和垂直变化的分辨率。这项研究由地球物理计划和国际科学与工程办公室共同资助，该办公室支持美国和巴西科学家之间的合作。