EAR-PF: Using distributions of channel geometry and channel belt properties to distinguish meandering and braided fluvial deposits in the rock record

EAR-PF：利用河道几何形状和河道带特性的分布来区分岩石记录中的曲流和辫状河流沉积物

基本信息

批准号：
1952814
负责人：
Tian Dong
金额：
$ 17.4万
依托单位：
Dong, Tian Y
依托单位国家：
美国
项目类别：
Fellowship Award
财政年份：
2020
资助国家：
美国
起止时间：
2020-09-01 至 2022-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1952814&HistoricalAwards=false
关键词：
EAR PF Using distributions channel

项目摘要

An NSF EAR Postdoctoral Fellowship has been granted to Dr. Tian Dong to carry out research and education plans at the University of Texas at Austin under the mentorship of Dr. Timothy Goudge. This project will study the distinctions between the two dominant river morphologies observed on Earth: single-thread and braided patterns. Distinguishing between these river types is straightforward in the modern environment as they can be directly observed or predicted using hydrological data. However, distinguishing channel patterns in the sedimentary rock record has proven more difficult, as only remnants of the river channels are preserved and they only account for a small fraction of the overall record. Identifying channel patterns in geologic records is important for predicting the quality and heterogeneity of groundwater and hydrocarbon reservoirs. Through this project, a new set of metrics will be developed for distinguishing river types using distributions of the dimensions of river channels and channel belts (i.e., collections of channel deposits from the same river at different times), measured from modern rivers on Earth using remote sensing data. These metrics will then be interpreted in the context of distinguishing between river types in the ancient rock record, with the anticipated findings relevant for the security of energy and water resources in the United States and related industries. This project also aims to promote participation of underrepresented groups in STEM fields at all levels (K-12 and undergraduate) through outreach programs such as GeoFORCE and research opportunities at the University of Texas at Austin.Formation of the two main river morphologies, single-thread and braided patterns can be relatively well predicted in modern environments using hydraulic variables of channel slope, width, depth, and water discharge. However, recognition of channel patterns in the rock record is difficult because only remnants of the original river channels are preserved. Since hydraulic variables such as slope and discharge cannot be measured directly in rock formations, this work will rely on geologic proxies. In addition to the significance of distinguishing river types to assess subsurface reservoir quality, this distinction is important for testing the hypothesis that whether single-thread rivers were rare prior to the arrival of land plants in the Silurian (~415 to 445 Ma). Previous studies have reconstructed the above four hydraulic variables to distinguish channel patterns in the rock record, but such results have uncertainties that range up to an order of magnitude due to compounded calculation errors. This study proposes to develop new diagnostic metrics using distributions of hydraulic variables and channel belt properties (e.g., width and radius of curvature), measured from modern fluvial systems worldwide via remote sensing techniques, with the ultimate aim for distinguishing channel types in the rock record. Specifically, we aim to test the hypothesis that braided and single-thread rivers have distinct distributions of channel geometry and channel belt properties as supported by theories on river branching. We anticipate that the results of this study will be widely applicable, as geometry variables, such as width and depth, and channel belt width are easily measurable or can be reconstructed with minimum calculation steps across observational length scales, from outcrops to seismic images, timescales, from modern systems to ancient sedimentary deposits, and across localities, from Earth to other planets. This project received co-funding from the Geomorphology and Land-use Dynamics program in the Earth Science division.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.

田东博士获得 NSF EAR 博士后奖学金，在 Timothy Goudge 博士的指导下在德克萨斯大学奥斯汀分校开展研究和教育计划。该项目将研究地球上观察到的两种主要河流形态之间的区别：单线和辫状模式。在现代环境中区分这些河流类型很简单，因为可以使用水文数据直接观察或预测它们。然而，事实证明，区分沉积岩记录中的河道模式更加困难，因为仅保留了河道的残余物，并且它们仅占整个记录的一小部分。识别地质记录中的河道模式对于预测地下水和碳氢化合物储层的质量和非均质性非常重要。通过该项目，将开发一套新的指标，用于使用河道和河道带尺寸的分布（即不同时间同一条河流的河道沉积物的集合）来区分河流类型，这些指标是从地球上的现代河流中测量的遥感数据。然后，这些指标将在区分古代岩石记录中的河流类型的背景下进行解释，预期的发现与美国及相关行业的能源和水资源安全相关。该项目还旨在通过 GeoFORCE 等外展计划和德克萨斯大学奥斯汀分校的研究机会，促进各级（K-12 和本科生）STEM 领域代表性不足的群体的参与。形成两种主要河流形态，即单一河流在现代环境中，使用渠道坡度、宽度、深度和排水量等水力变量，可以相对较好地预测线状和编织状图案。然而，识别岩石记录中的河道模式很困难，因为仅保留了原始河道的残余物。由于坡度和流量等水力变量无法直接在岩层中测量，因此这项工作将依赖于地质代理。除了区分河流类型对于评估地下储层质量的重要性之外，这种区别对于检验以下假设也很重要：在陆地植物到达志留纪（~415 至 445 Ma）之前，单线河流是否很少见。先前的研究已经重建了上述四个水力变量来区分岩石记录中的河道模式，但由于复合计算误差，这些结果具有高达一个数量级的不确定性。本研究建议利用通过遥感技术从全球现代河流系统测量的水力变量和河道带特性（例如宽度和曲率半径）的分布来开发新的诊断指标，最终目标是区分岩石记录中的河道类型。具体来说，我们的目的是检验以下假设：辫状河和单线河具有不同的河道几何形状和河道带特性分布，这一点得到河流分支理论的支持。我们预计这项研究的结果将得到广泛应用，因为宽度和深度以及河道带宽度等几何变量很容易测量，或者可以在整个观测长度尺度（从露头到地震图像、时间尺度）上以最少的计算步骤进行重建，从现代系统到古代沉积物，跨越地点，从地球到其他行星。该项目获得了地球科学部门地貌学和土地利用动力学项目的共同资助。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。