Final stages of breakup and early spreading history of the Eastern North America passive margin from multichannel seismic data

多道地震数据显示北美东部被动边缘破裂的最后阶段和早期扩张历史

• 批准号: 1551807
• 负责人: Anne Becel
• 金额: $ 20万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-03-15 至 2019-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1551807&HistoricalAwards=false
• 关键词: Final; stages; breakup; early; spreading

Rifted passive margins record the full geologic history of rifting, from rift onset to continental breakup to the initiation of seafloor spreading and post-rift evolution of the margin. This project focuses on the Eastern North America continental margin offshore Cape Hatteras that was formed after the breakup of supercontinent Pangaea. A large suite of data has been collected across the transition from continental crust to oceanic crust in this region. These data will be analyzed and interpreted to obtain an improved understanding of events surrounding the final stage of continental breakup including the relationship between the timing of rifting and the occurrence of offshore magmatism and early opening of the Central Atlantic Ocean. The project will also provide new information on landslides that have occurred along the margin of the U.S. and an estimate of the number of landslides that might have produced tsunamis. A postdoctoral researcher will be trained in geophysical data analysis and interpretation, and the results of the proposed work will be incorporated into outreach programs for high school and middle school students.This project consists of the processing and interpretation of offshore, long-offset multichannel seismic (MCS) data from the Eastern North American Margin. The long-offset MCS data analysis will provide critical new information about the along-strike variations of the complex transitional crust between unambiguous continental and oceanic crust at a smaller-scale than previous studies. The crustal-scale closely-spaced MCS profiles will be essential to image the small-scale heterogeneities of the volcanic products along the margin, spatial patterns in basement topography, thickness of sediment and rift unconformities within the sediments and features within the crust and lithosphere (e.g., faults and crustal thickness variations). MCS imaging of those features are needed to assess the late-stage rifting processes and variations in time and space of these processes. Different kinematic plate models for the earliest stage of evolution of the Central Atlantic Ocean make very different predictions for the half spreading rate. In addition, large-scale segmentation at the modern Mid-Atlantic ridge has also been proposed to be inherited from the geometry of the adjacent continental margin. MCS data from this project will constrain variations in basement roughness, crustal thickness and crustal structure and reflectivity along and across new oceanic crust that will provide important constraints on the early seafloor spreading history and will help to distinguish between competing models.

裂痕被动边缘记录了裂谷的完整地质历史，从裂谷到大陆分裂，再到海底蔓延和边缘后裂地的启动。该项目着重于北美东部的大陆边缘海上哈特拉斯海角，该海角是在超大型潘吉亚（Pangea）分手之后成立的。从该地区的大陆地壳到海洋地壳的过渡，已经收集了大量数据。 这些数据将进行分析和解释，以提高对围绕大陆分裂最后阶段的事件的了解，包括裂谷时机与海上岩浆岩的发生与中央大西洋的早期开放之间的关系。 该项目还将提供有关在美国边缘沿线发生的滑坡的新信息，并对可能产生海啸的滑坡数量进行估计。 博士后研究人员将接受地球物理数据分析和解释的培训，拟议工作的结果将纳入高中和中学生的外展计划中。该项目包括从北美东部美国东部北美地区的离岸，长期偏移多渠道多渠道地震（MCS）数据的处理和解释。长期偏移的MCS数据分析将提供有关在较小的研究时在明确的大陆和海洋壳之间复杂过渡地壳的及突发性变化的关键新信息。地壳尺度紧密的MCS轮廓对于沿边缘的火山产品的小尺度异质性，地下室地形中的空间图案，沉积物的厚度和裂纹内部的厚度和裂谷不整合物的空间图案至关重要。需要对这些特征进行MCS成像来评估这些过程的时期和空间的后期裂谷过程和变化。对于中部大西洋的最早进化阶段的不同运动板模型对半扩散率的预测非常不同。此外，还认为现代中大西洋山脊的大规模分割是从相邻大陆边缘的几何形状继承的。该项目的MCS数据将限制地下室粗糙度，地壳厚度和地壳结构以及沿新的海洋外壳的反射率的变化，这将为早期海底扩散历史提供重要限制，并有助于区分竞争模型。