Electromagnetic imaging of lithospheric and environmental targets

电磁（EM）成像为回答从大尺度（如北美在过去30亿年里是如何形成和变形的）到小尺度（如二氧化碳气体在浅层地下的分布情况）的问题提供了关键信息。电磁研究包括记录和分析地球上由电离层和大气中的源以及包括通电线圈和电线在内的人造源产生的信号。不同频率和来源的信号可穿透不同深度，从而实现多尺度成像。提出的研究将解决地球物理学和地质学的界面问题，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、两名硕士和两名学士（荣誉）学生，为他们提供在构造研究、资源勘探、可持续发展和环境监测方面至关重要的高级知识和技能。******研究的第一部分将使用深穿透大地电磁（MT）方法研究苏必利尔省、哈德逊湾盆地和加拿大北部科迪勒拉的大陆地壳和岩石圈。目标包括绘制岩石圈厚度，描绘可追踪流体输送和地壳缝线的导电带，以及定义各向异性（方向变化）电阻率。这项工作将提供有关构造过程和小尺度地质构造的新信息。除了提高MT解释的准确性和增加现有国家数据集的实质性价值外，结果还将为碳氢化合物，钻石和矿床的勘探提供重要信息。******研究的第二个组成部分是萨斯喀彻温省埃斯特文的aqueststore现场二氧化碳注入的EM成像。aquestore正被用于研究深层沉积盆地中二氧化碳的封存，作为减少温室气体的一种方法，它是全球为数不多的此类研究地点之一。该项目涉及将相当成熟的电磁方法应用于一个新目标，即位于发电站附近的一个3.4公里深的二氧化碳储层单元。在过去的四年里，我们收集了大量的MT和可控源EM （CSEM）数据。拟开展的研究包括全面表征CSEM数据，包括测量响应的可重复性，以及确定储层与地表之间的注前电阻率结构。该项目将对地面电磁方法监测大陆深层储层中二氧化碳封存的能力进行具有国际意义的评估，并对使用封存方法长期减少温室气体具有重要意义。

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.