The sedimentary dynamics of fine-grained rivers: a novel application of marine geophysics to develop new fluvial facies models

关于沙质或砾石河床的河流是如何运行的，以及这些过程如何导致典型的沉积特征，如点状沙洲，人们已经知道了很多。相比之下，那些以更细颗粒的沉积物为主的沉积物则鲜为人知。尤其是他们的沉积物，例如，由于对这一基本知识的缺乏，有人认为河道内的细粒河流沉积物可能被错误地解释为漫滩沉积的环境。因此，对于细粒河流的不同积木是如何组合在一起的，以及哪些因素可能控制这些积木，人们知之甚少。简而言之，细粒河流的科学落后于沙质/砾石河流。这在很大程度上可以归因于这样一个事实，即给砂砾河床河流研究带来革命性变化的地球物理技术根本不适用于细粒河流。例如，对于最流行的技术之一--探地雷达，信号的性质在细粒度环境中受到严重影响，以至于无法收集数据。这项提议试图通过应用一种更常用于海洋和三角洲环境的地球物理技术来解决这一缺点。参数回声探测仪已被证明有能力从细粒沉积物中产生高分辨率数据。通过应用一种新的交叉技术，该提议的目的是在河流环境中使用该技术，以产生第一个大范围的、三维的细粒河流沉积学的量化。这一点很重要，因为古岩石中的微粒将严重影响水和石油/天然气的移动能力。因此，能够充分了解细粒沉积物，以便在储集层模型中适当考虑它们，具有显著的社会效益(来自含水层的饮用水供应)和经济效益(碳氢化合物的成功回收)。

A lot is known about how rivers with sandy or gravelly beds operate and how these processes lead to characteristic depositional features such as point bars. By comparison, those dominated by finer-grained sediments are much less well understood. This is especially the case for their deposits, for example, as a result of this basic lack of knowledge it has been suggested that within channel fine-grained river sediments may have been incorrectly interpreted to be environments of overbank floodplain sedimentation. Thus very little is known about how the different building blocks of a fine-grained river are put together and what factors may control these building blocks. In short, the science of fine-grained rivers lags that of sandy/gravelly ones. This can be attributed in large part to the fact that the geophysical techniques that have revolutionised the study of sand and gravel bed rivers simply do not work in fine-grained ones. For example, for one of the most popular techniques, ground penetrating radar, the nature of the signal is so severely affected in fine grained environments that no data can be collected. This proposal seeks to address this shortcoming through the application of a geophysical technique more normally used in marine and deltaic settings. The parametric echosounder has proven capability to generate high-resolution data from fine-grained sediments. By application of a novel cross-over of technology the aim of this proposal is to use this technique in a river environment to generate the first large-scale, 3-D quantification of fine-grained river sedimentology. This is important because fines in ancient rocks will severely impact the ability of water and oil/gas to move. There are thus significant social (drinking water supply from aquifers) and economic (successful recovery of hydrocarbons) benefits from being able to understand fine-grained sediments fully so that they can be properly taken in to account in reservoir models.