Fundamental rock magnetic studies on single-domain particles and anisotropy, and applications to paleomagnetism and petrophysics

本课程将研究岩石磁学的一些基本方面，以及它在古磁学和岩石物理学中的应用。地质历史上地球、月球、岩石行星和陨石的古磁场（古地磁）强度和方向的重要信息是由岩石中的稳定的小单畴（SSD）磁颗粒携带的。它们携带的磁性信息在岩石形成时被锁定（称为自然剩余磁化，NRM），并且可以在数百万年内保持稳定。这些信息对于了解岩石行星体的磁场历史，以及为重建地球上过去的板块构造运动提供数据至关重要。这个程序将研究固态硬盘粒子的一些基本性质。其中一个主要目的是改进各向异性岩石（其性质在不同方向上变化的岩石）的古磁场方向和强度的计算，这将使从迄今可能的更大范围的样品中获得有用的古磁学数据成为可能。这可能包括更早的样品，这些样品通常更具各向异性，并且以前可能没有生成可靠的古磁学数据。这反过来又有可能使更久远的板块构造重建成为可能。另一个关键方面将是研究比固态硬盘大小稍大的粒子的性质，并量化这些粒子转变为亚稳态单畴态的条件。这很重要，因为它可能有助于解释为什么岩石中NRM的很大一部分似乎存在于这些稍大的颗粒中。*******该计划还将研究被称为超顺磁性（SP）的较小单畴粒子的基本性质。虽然这些颗粒没有保留剩余的磁性，因此在古磁学方面并不重要，但我们正在率先将它们用作纳米颗粒造影剂。它们的高磁化率和小尺寸使其成为监测水力压裂作业进度和环境影响、监测油砂生产过程以及其他对加拿大经济重要的应用的理想示踪剂。*******该项目的另一个目的是进一步建立岩石磁性和岩石物理参数之间的联系。特别是，我们的目标是量化磁各向异性与其他关键岩石物性（如流体渗透率各向异性、声学各向异性、电各向异性）的各向异性之间的关系。这可能会提供一种通过快速、非破坏性磁各向异性技术来估计其他岩石物理性质的方法。这将在页岩油气和其他类型的储层中具有重要的应用价值，其中各向异性是一个关键因素

This program will study some fundamental aspects of rock magnetism, and its application to paleomagnetism and petrophysics. Important information concerning the intensity and direction of the ancient magnetic fields (paleomagnetism) of the Earth, Moon, rocky planets and meteorites in the geological past is carried by small stable single-domain (SSD) magnetic particles in rocks. The magnetic information they carry is locked-in when the rock is formed (called a natural remanent magnetization, NRM), and can remain stable over millions of years. This information is crucial for understanding the magnetic history of rocky planetary bodies, and for providing the data for reconstructing past plate tectonic motions on the Earth. This program will study some fundamental properties of SSD particles. One of the main aims is to improve computations of the ancient field direction and intensity from anisotropic rocks (rocks whose properties vary in different directions), which would enable useful paleomagnetic data to be obtained from a wider range of samples than has hitherto been possible. This could include older samples that are often more anisotropic and where reliable paleomagnetic data may not previously have been generated. This in turn could potentially allow plate tectonic reconstructions to be made further back in time. Another key aspect will be studying the properties of particles slightly larger than SSD size, and quantifying the conditions under which these particles can transform into metastable single-domain states. This is important since it may help to explain why a significant fraction of the NRM in rocks appears to reside in these slightly larger particles.*******The program will also study the fundamental properties of smaller single-domain particles that are termed superparamagnetic (SP). Whilst these particles do not retain a remanent magnetization, and are therefore not important in terms of paleomagnetism, we are pioneering their use as nanoparticle contrast agents. Their high magnetic susceptibility and small size makes them ideal tracers for monitoring the progress and environmental effects of hydraulic fracturing operations, monitoring production processes in the oil sands, and other applications important to the Canadian economy.*******Another aim of the program is to further establish links between rock magnetism and petrophysical parameters. In particular, we aim to quantify the relationships between magnetic anisotropy and the anisotropies of other key petrophysical properties (such as fluid permeability anisotropy, acoustic anisotropy, electrical anisotropy). This potentially will provide a means of estimating these other petrophysical properties from rapid, non-destructive magnetic anisotropy techniques. This would have important applications for optimizing production in shale oil and gas plays, and other types of reservoir where anisotropy is a key factor.***