EAR-PF: A channel-belt scale source of autogenic topography controlling fluvial sedimentation and preservation: Investigation using 3D seismic volumes

EAR-PF：控制河流沉积和保存的自生地形的河道带尺度源：使用 3D 地震体进行调查

• 批准号: 2052912
• 负责人: Benjamin Cardenas
• 金额: $ 17.4万
• 依托单位: Cardenas, Benjamin
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-01 至 2022-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2052912&HistoricalAwards=false
• 关键词: EAR; PF; channel; belt; scale

Rivers are important resources and are major shapers of the Earth’s surface. Understanding their evolution over time is important with changing climate, yet to understand how rivers evolve over longer than human timescales, we need to examine the sedimentary deposits created by ancient rivers. These deposits record the evolution and migration of rivers over long timescales before being buried. However, while external forces such as changing climate and tectonics can influence the evolution of rivers, there are also internally controlled factors related to spatially variable flow and sediment deposition that may shape river deposits. By repurposing 3D acoustic images collected by the energy industry showing river deposits in Earth’s subsurface, we will examine the deposits of ancient coastal rivers to better understand how these important deposits vary over space and time, and why. The results of this work will help us better understand how and why ancient rivers have modified Earth’s surface, and will help us predict future changes. It has long been recognized that the sedimentary record is often complicated and obscured by time-variable sedimentation, hiatus, and erosion. Exceptions have been recognized primarily at the bedform scale, where local, naturally occurring (autogenic) relief drives rapid sedimentation and preservation. River-channel belts, the sedimentary deposits created by river migration and aggradation over time, are also commonly well preserved at the scale of tens of kilometers. This exceptional preservation is often attributed to external forcings (e.g., subsidence), but autogenic sources of topography at the channel-belt scale have also been recognized and hypothesized to be an important source of autogenic relief. Inter-alluvial-ridge basins may perform this function. To quantify the relative importance of autogenic and allogenic processes in preserving fluvial channel belts, we will use 3D seismic volumes imaging the subsurface of the Gulf of Mexico. Using volumes across the continental shelf, we will map channel belts, build a database of channel-belt geometries, and identify the drivers of their preservation, ultimately tracking the relative importance of autogenic and allogenic processes in preserving channel belts across the Gulf Coast over time. Part of our workflow involves converting analyzed 3D seismic volumes to 3D Numpy arrays, a free, open-source, and easily manipulated dataset, which we will make freely available to make 3D seismic volumes more accessible.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

河流是重要的资源，是地球表面的主要塑造者。了解河流随时间的演变对于气候变化非常重要，但要了解河流如何在比人类时间尺度更长的时间内演变，我们需要检查古代河流形成的沉积物。这些沉积物记录了河流在被埋藏之前在很长一段时间内的演变和迁移。然而，虽然气候和构造变化等外部力量可以影响河流的演化，但也存在与空间变化的流量和沉积物沉积相关的内部控制因素，这些因素可能会影响河流的沉积。通过重新利用能源行业收集的显示地球地下河流沉积物的 3D 声学图像，我们将检查古代沿海河流的沉积物，以更好地了解这些重要沉积物如何随空间和时间变化以及原因。这项工作的结果将帮助我们更好地了解古代河流如何以及为何改变了地球表面，并将帮助我们预测未来的变化。人们早就认识到，沉积记录常常因时变沉积、间断和侵蚀而变得复杂和模糊。主要在地床形态尺度上认识到了例外情况，其中局部自然发生的（自生）地势推动了快速沉积和保存。河道带是河流随时间迁移和加积而形成的沉积物，通常也保存完好，规模达数十公里。这种特殊的保存通常归因于外部强迫（例如沉降），但河道带尺度的自生地形来源也已被认识并假设为自生地势的重要来源。冲积脊间盆地可以发挥这一功能。为了量化自生和异生过程在保护河流河道带方面的相对重要性，我们将使用 3D 地震体对墨西哥湾地下进行成像。利用整个大陆架的体积，我们将绘制河道带地图，建立河道带几何形状数据库，并确定其保存的驱动因素，最终跟踪随着时间的推移自生和同种异体过程在保护整个墨西哥湾沿岸的河道带方面的相对重要性。我们工作流程的一部分涉及将分析的 3D 地震体转换为 3D Numpy 阵列，这是一个免费、开源且易于操作的数据集，我们将免费提供该数据集，以使 3D 地震体更易于访问。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。