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

裂谷被动边缘记录了裂谷作用的完整地质历史，从裂谷开始到大陆裂解，再到海底扩张的开始和裂谷后边缘的演化。该项目的重点是北美东部大陆边缘近海的哈特拉斯角，它是在超大陆盘古大陆解体后形成的。在该地区从陆壳到洋壳的过渡过程中收集了一大套数据。这些数据将被分析和解释，以更好地了解围绕大陆解体最后阶段的事件，包括裂谷作用的时间与近海岩浆活动的发生和大西洋中部早期开放之间的关系。该项目还将提供有关美国边缘地区发生的山体滑坡的新信息，以及对可能引发海啸的山体滑坡数量的估计。一名博士后研究人员将接受地球物理数据分析和解释方面的培训，拟议工作的结果将被纳入针对高中生和中学生的推广计划。该项目包括处理和解释北美东部边缘的海上、长炮检距多道地震(MCS)数据。长炮检距MCS数据分析将提供有关明确的陆壳和洋壳之间复杂过渡地壳沿走向变化的关键新信息，其规模比以前的研究要小。地壳尺度的近距离MCS剖面对于成像边缘火山产物的小尺度非均质性、基底地形的空间格局、沉积物中的沉积物厚度和裂谷不整合以及地壳和岩石圈内的特征(例如断层和地壳厚度变化)至关重要。需要对这些特征进行MCS成像，以评估后期裂谷过程以及这些过程在时间和空间上的变化。中大西洋最早演化阶段的不同运动板块模型对一半的扩张速度做出了非常不同的预测。此外，现代中大西洋海脊的大尺度分段也被认为是从邻近大陆边缘的几何形状继承而来的。该项目的MCS数据将约束新洋壳沿线和跨洋壳的基底粗糙度、地壳厚度和地壳结构和反射率的变化，这将为早期海底扩张史提供重要约束，并将有助于区分相互竞争的模型。

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.