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。随着气候的变化，了解河流随时间的演变是很重要的，但要了解河流是如何在比人类时间尺度更长的时间内进化的，我们需要研究古代河流形成的沉积物。这些沉积物在被掩埋之前记录了河流在很长时间尺度上的演化和迁移。然而，虽然气候变化和构造变化等外部力量可以影响河流的演变，但也存在与空间变化的流量和沉积物沉积有关的内部控制因素，这些因素可能会塑造河流沉积物。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理解古代河流如何以及为什么改变了地球表面，并将帮助我们预测未来的变化。长期以来，人们一直认识到沉积记录往往是复杂的，并因随时间变化的沉积、沉积间隙和侵蚀而模糊不清。例外情况主要发生在河床尺度上，在那里，局部的、自然发生的（自生的）起伏推动了快速的沉积和保存。河道带是河流长期迁移和淤积形成的沉积物，通常在几十公里的尺度上保存得很好。这种特殊的保存通常归因于外部强迫（如下沉），但在河道带尺度上的自生地形源也被认为是自生地形的重要来源，并被假设为自生地形源。冲积脊间盆地可能发挥这一作用。为了量化自生和异体过程在保存河道带中的相对重要性，我们将使用墨西哥湾地下三维地震体成像。利用整个大陆架的体积，我们将绘制水道带，建立水道带几何形状的数据库，并确定其保存的驱动因素，最终追踪自生和异体过程在保存墨西哥湾沿岸水道带中的相对重要性。我们的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，这是一个免费的，开源的，易于操作的数据集，我们将免费提供，使3D地震体更容易访问。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。