Fundamental rock magnetic studies on single-domain particles, impressed magnetic anisotropy, and the application of rock magnetic techniques to petrophysics

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This program will study some fundamental and applied aspects of rock magnetism. Important information concerning the intensity and direction of the Earth's ancient magnetic field (paleomagnetism) is carried by small stable single-domain (SD) particles in rocks. The information they carry is locked-in when the rock is formed, and can remain stable over millions of years. This program will study the fundamental properties of SD particles, and extend our recent discoveries. In particular, we have recently demonstrated that there is a range of stable positions in which the magnetic moment can lie in SD particles. Understanding this important feature potentially allows improved computations of the ancient field direction and intensity to be made from anisotropic rocks. This potentially allows useful paleomagnetic data to be obtained from a wider range of samples than are generally currently studied (including older samples, which are often more anisotropic and disregarded due to difficulties in estimating reliable paleomagnetic data from them). We will also be examining the properties of particles slightly larger than SD size, and quantifying the conditions under which these particles can transform into a metastable SD state. This is extremely important since it may help to explain why a significant fraction of the natural remanent magnetization (NRM) in rocks appears to reside in these slightly larger particles.