Electromagnetic studies of crustal fluids and dynamics

流体，如水和部分熔体，广泛分布在地球内部。它们之所以重要，是因为它们参与了许多地质过程，例如矿藏的形成和地热系统中的热量传递。此外，流体可以改变岩石的强度，并控制地球构造板块在板块边界处的变形。***测绘地球内部的流体分布需要使用在地表测量的地球物理数据来确定深部岩石的性质。地震成像利用声波，是油气勘探中应用最广泛的技术之一。电磁勘探方法利用低频无线电波对地下进行成像，是矿产和地热勘探的重要工具。大地电磁（MT）是一种电磁方法，它使用自然的低频无线电信号来确定从地表到几百公里深处的电阻率。在本提案中，将开展研究，通过结合多种类型的地球物理和地质数据，提高MT可靠成像地下流体的能力。这些方法将应用于许多问题。按照深度的增加顺序，这些是(1)加拿大西部的地热勘探，那里的MT数据将被用来定位电力生产资源；(2)在智利对一个非常活跃的岩浆体的研究，该岩浆体显示出向一次主要火山喷发移动的迹象；(3)对秘鲁俯冲带的调查，在那里，当今的板块结构将与地壳和地幔的流体组成有关。这第三项研究将用于更好地理解导致当今资源分布的地质过程。这些结果将为科学家模拟发生在俯冲带的过程提供有价值的新信息。这包括地壳和地幔的性质，以及可能引起大喷发的浅层岩浆房的组成和时间变化。这项研究将有助于开发加拿大西部的地热资源，从而减少对化石燃料的依赖，从而使加拿大受益。它还将开发可用于地热和矿物工业的改进成像方法。在南美洲进行的研究将有助于了解俯冲带的行为，重点是火山爆发前岩浆体的行为和板块俯冲发生的角度。加拿大太平洋海岸的一部分位于俯冲带之上，新的结果将为与该板块边界相关的现象和危险提供更好的背景。一个额外的好处是培训这些方法的研究生，他们将有资格在地热、矿物和碳氢化合物工业中担任地球物理学家。**

Fluids, such as water and partial melt, are widely distributed in the interior of the Earth. They are important because they are involved in many geological processes, such as the formation of mineral deposits and the transfer of heat in geothermal systems. In addition, fluids can change the strength of rocks and control how the Earth's tectonic plates will deform at plate boundaries. ***Mapping fluid distribution within the Earth requires the use of geophysical data measured at the surface to determine the properties of rocks at depth. Seismic imaging uses sound waves and is one of the most widely used techniques in oil and gas exploration. Electromagnetic exploration methods use low frequency radio waves to image the subsurface and are important tools in mineral and geothermal exploration. Magnetotellurics (MT) is an electromagnetic method that uses natural, low frequency, radio signals to determine the electrical resistivity from the surface to a depth of several hundred kilometers. In this proposal, research will be carried out that will improve the ability of MT to reliably image subsurface fluids, by combining multiple types of geophysical and geological data. ***These methods will be applied to a number of problems. In order of increasing depth, these are (1) geothermal exploration in Western Canada where the MT data will be used to locate resources for electric power production (2) studies in Chile of a very active magma body that shows signs of moving towards a major volcanic eruption and (3) an investigation of the subduction zone in Peru where the present day plate structure will be related to the fluid composition of the crust and mantle. This third study will be used to better understand the geological processes that led to the present day distribution of resources. ***The results will give valuable new information to scientists modelling the processes that occur at subduction zones. This includes the properties of the crust and mantle and the composition and time variations of shallow magma chambers that may cause large eruptions. This research will benefit Canada by helping to develop geothermal resources in Western Canada, and thereby reducing dependence on fossil fuels. It will also develop improved imaging methods that can be used in the geothermal and mineral industries. The studies in South America will help understand the behaviour of subduction zones, with an emphasis on the behaviour of magma bodies prior to volcanic eruptions and the angle at which plate subduction occurs. Part of Canada's Pacific coast is located above a subduction zone, and the new results will give an improved context for the phenomena and hazards associated with this plate boundary. An additional benefit will be the training of graduate students in these methods who will be qualified to work as geophysicists in the geothermal, mineral and hydrocarbon industries. **