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。了解它们随时间的演变对气候变化很重要，但要了解河流如何在比人类更长的时间尺度上演变，我们需要研究古代河流形成的沉积物。这些沉积物记录了河流在被掩埋之前的长时间尺度上的演变和迁移。然而，虽然外部力量，如气候和构造的变化可以影响河流的演变，也有内部控制的因素与空间变化的流量和沉积物沉积，可能形成河流沉积。通过重新利用能源行业收集的3D声学图像，显示地球地下的河流沉积物，我们将研究古代沿海河流的沉积物，以更好地了解这些重要的沉积物在空间和时间上的变化以及原因。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什么改变了地球表面，并将帮助我们预测未来的变化。人们早就认识到，沉积记录往往是复杂的，并被随时间变化的沉积、间断和侵蚀所掩盖。沉积物主要是在床形尺度上被认识到的，在这种尺度上，局部的、自然发生的（自生的）起伏推动了快速的沉积和保存。河道带是河流随时间推移而迁移和加积形成的沉积物，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），但也已认识到，并假设水道带规模的地形自生来源是自生地貌的重要来源。冲脊间盆地可发挥这一作用。为了量化自生和异体过程在保存河流河道带的相对重要性，我们将使用三维地震体积成像墨西哥湾的地下。使用整个大陆架的体积，我们将绘制通道带，建立通道带几何形状的数据库，并确定其保存的驱动因素，最终跟踪自生和异体过程在保存整个墨西哥湾沿岸通道带的相对重要性。我们的部分工作流程包括将分析的3D地震体转换为3D Numpy阵列，这是一个免费、开源和易于操作的数据集，我们将免费提供，以使3D地震体更容易访问。该奖项反映了NSF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。