Electromagnetic imaging of lithospheric and environmental targets

电磁（EM）成像提供的信息对于回答从非常大规模的问题至关重要，例如北美在过去30亿年中是如何形成和变形的，到小规模的问题，例如CO2气体如何分布在浅层地下。EM研究涉及记录和分析地球上电离层和大气中的源以及包括通电线圈和电线在内的人工源产生的信号。具有不同频率和来源的信号穿透到不同的深度，从而能够在多个尺度上成像。拟议的研究将解决地球物理学和地质学界面的问题，检查控制电导率的参数，并提取有关构造，地质和环境过程的信息。它将包括培训一名访问学者和至少一名博士，两个硕士学位，和两名B.Sc.（荣誉）学生，为他们提供高层次的知识和技能，在构造研究，资源勘探，可持续发展和环境监测的关键。 研究的第一部分将使用深穿透大地电磁法研究上级省、哈德逊湾盆地和北方加拿大科迪勒拉山脉的大陆地壳和岩石圈。目标包括绘制岩石圈厚度，描绘导电区，跟踪流体输送和地壳缝合线，并定义各向异性（方向变化）电阻率。这项工作将提供关于构造过程和较小规模地质结构的新信息。除了提高MT解释的准确性和增加现有国家数据集的重要价值外，其结果还将为碳氢化合物、钻石和矿藏的勘探提供重要信息。 该研究的第二个组成部分是在萨斯喀彻温省埃斯特万的Aquistore现场注入CO2的EM成像。Aquistore正被用来研究在深层沉积盆地中封存二氧化碳，作为减少温室气体的一种方法，它是全球为数不多的这类研究地点之一。该项目涉及应用相当成熟的EM方法到一个新的目标，一个3.4公里深的CO2水库位于附近的发电站。在过去的四年里，我们已经收集了大量的MT和受控源EM（CSEM）数据库的网站。拟议的研究涉及全面表征CSEM数据，包括测量响应的可重复性，并确定储层区和地表之间的注入前电阻率结构。该项目将提供一个具有国际重要性的评估能力的表面EM方法监测CO2封存在深大陆水库和具有意义的长期减少温室气体的封存方法。

Electromagnetic (EM) imaging provides information critical for answering questions from the very large-scale, such as how North America has formed and been deformed over the last 3 billion years, to the small-scale, such as how CO2 gas is distributed in the shallow sub-surface. EM studies involve recording and analyzing signals produced in the Earth by sources in the ionosphere and atmosphere and artificial sources including energized coils and wires. Signals with different frequencies and sources penetrate to different depths enabling imaging over multiple scales. The proposed research will address questions at the interface of geophysics and geology, examining parameters controlling electrical conductivity, and extracting information on tectonic, geological, and environmental processes. It will include training of a visiting scholar and at least one Ph.D., two M.Sc., and two B.Sc. (Honours) students, providing them with high-level knowledge and skills critical in tectonic studies, resource exploration, sustainable development, and environmental monitoring. The first component of the research will use the deep-penetrating magnetotelluric (MT) method to study continental crust and lithosphere in the Superior Province, Hudson Bay Basin, and northern Canadian Cordillera. Objectives include mapping lithospheric thickness, delineating conductive zones that trace fluid transport and crustal sutures, and defining anisotropic (directionally-varying) resistivity. This work will provide new information on tectonic processes and smaller-scale geological structures. In addition to improving the accuracy of MT interpretations and adding substantial value to existing national data sets, the results will provide important information for exploration for hydrocarbon, diamond, and mineral deposits. The second component of the research is EM imaging of CO2 injection at the Aquistore site at Estevan, Saskatchewan. Aquistore is being used to investigate the sequestering of CO2 in deep sedimentary basins as a method of greenhouse gas reduction and is one of a small number of such study sites globally. The project involves application of fairly well established EM methods to a new target, a 3.4 km deep CO2 reservoir unit located in the vicinity of a power station. Over the last four years we have collected a large data base of MT and controlled-source EM (CSEM) data at the site. The proposed research involves fully characterizing the CSEM data, including the repeatability of the measured responses, and determination of the pre-injection resistivity structure between the reservoir zone and the surface. The project will provide an internationally-important evaluation of the capacity of surface EM methods for monitoring CO2 sequestration in deep continental reservoirs and has significance for long-term reduction in greenhouse gases using sequestration methods.