Acquisition of a Sensitive Magnetic Susceptibility System and a Reflected Light Microscope for Studies of Self-Reversal in Titanomaghemite

一些岩石在与地球磁场相反的方向上获得磁化的显著能力，或自然剩余磁化的自逆转被认为是罕见的；这种能力只存在于少数含有赤铁矿的火成岩中。罗切斯特的古地磁实验室报告了两个几乎相反的磁化成分，通过详细的热去磁研究，发现了枕状玄武岩中没有铁铁矿的磁化成分。实验室部分热剩余磁化的应用表明，在较低温度下分离的组分代表初级磁化的部分自反转。由于洋壳的磁赤化作用无处不在，部分自逆转可能对过去3000万年形成的地壳的海洋磁异常幅度随年龄的下降做出重要贡献。这笔赠款将用于购买两个设备系统，以帮助进一步研究大洋玄武岩中钛磁铁矿携带的自逆转的程度和机制：(1)带有居里点测定炉具的磁化率系统和(2)用于基本表征磁相的反射光学显微镜系统。该设备将支持一篇博士论文和几名本科生的论文研究。这些设备还将支持其他研究生、本科生和博士后研究人员继续从事地磁学、构造学、岩石磁学和环境磁学的研究，以及在罗切斯特大学进行正式课程教学。

0236383TardunoThe remarkable ability of some rocks to acquire a magnetization in a direction antiparallel to the Earth's geomagnetic field, or self-reversal of natural remanent magnetization, is thought to be rare; it has been established only in a few igneous rocks bearing hemoilmenite. The paleomagnetism lab at Rochester has reported on two, nearly antipodal components of magnetization, revealed through detailed thermal demagnetization studies, from pillow basalts in which hemoilmenite is absent. Application of laboratory partial thermoremanent magnetizations have shown that the component isolated at lower temperatures represents a partial self-reversal of the primary magnetization. Because maghemitization of oceanic crust is ubiquitous, partial self-reversals may make an important contribution to the decrease in marine magnetic anomaly amplitudes with age observed for crust formed during the last 30 million years.Funds from this grant will be used to acquire two equipment systems to assist in further investigations of the extent and mechanism of self-reversal carried by titanomaghemite in oceanic basalt: (1) a magnetic susceptibility system with a furnace apparatus for Curie point determinations and (2) a reflected light microscope system for basic characterization of magnetic phases. The equipment will support a Ph.D. thesis and the thesis studies of several undergraduate students. The equipment will also support the continuing work of other graduate students, undergraduates and postdoctoral researchers conducting studies in geomagnetism, tectonics, rock magnetism and environmental magnetism, and in formal course instruction at the University of Rochester.***