Electrical resistivity imaging of the architecture of substream sediments
Electrical resistivity imaging of the architecture of substream sediments
复制标题
支流沉积物结构的电阻率成像
DOI：
10.1029/2008wr006968
复制
发表时间：
2008
影响因子：
5.4
通讯作者：
Roy Haggerty
中科院分区：
文献类型：
--
作者：
N. Crook;A. Binley;Rosemary Knight;David A. Robinson;J. Zarnetske;Roy Haggerty
由于缺乏有关河床沉积物连续性和结构的空间信息，对河流系统的模拟受到限制。对河床进行非侵入性表征的方法很少。使用油井和岩心的侵入性方法无法提供关于主流建筑及其连续性的详细空间信息。地球物理技术在提供许多其他环境中地下属性和过程的空间信息方面发挥着关键作用，我们已经将其中一项技术应用于河床。通过两个例子，我们演示了如何利用电阻率成像来表征子通道的结构。在第一个例子中，安装在河岸钻孔和河床上的电极被用来在河床下成像覆盖在白垩岩上的高渗透性冲积砾石层的厚度和连续性。在第二个例子中，根据安装在河床上的电极收集的数据确定的电阻率图像提供了对原木堵塞后沉积物体积的约束估计，这对于模拟生物地球化学交换至关重要，由于河流中的巨石含量，使用传统钻探方法无法进行测量。这两个例子表明，在复杂的河流环境中，非侵入性的电阻率成像是可能的，并提供了关于河流河道下的地下结构的有价值的信息。
The modeling of fluvial systems is constrained by a lack of spatial information about the continuity and structure of streambed sediments. There are few methods for noninvasive characterization of streambeds. Invasive methods using wells and cores fail to provide detailed spatial information on the prevailing architecture and its continuity. Geophysical techniques play a pivotal role in providing spatial information on subsurface properties and processes across many other environments, and we have applied the use of one of those techniques to streambeds. We demonstrate, through two examples, how electrical resistivity imaging can be utilized for characterization of subchannel architecture. In the first example, electrodes installed in riparian boreholes and on the streambed are used for imaging, under the river bed, the thickness and continuity of a highly permeable alluvial gravel layer overlying chalk. In the second example, electrical resistivity images, determined from data collected using electrodes installed on the river bed, provide a constrained estimate of the sediment volume behind a log jam, vital to modeling biogeochemical exchange, which had eluded measurement using conventional drilling methods owing to the boulder content of the stream. The two examples show that noninvasive electrical resistivity imaging is possible in complex stream environments and provides valuable information about the subsurface architecture beneath the stream channels.