SGER: Magnetic Inclusions in Diamonds

这是一项初步研究，旨在利用钻石中磁黄铁矿包裹体的存在：1)潜在的地球磁场强度记录器；2)验证基于高压下磁黄铁矿磁性的假设。PI的初步结果令人震惊，因为这些钻石中的包裹体具有很强的磁性，或许更令人惊讶的是，它们被稳定地磁化。研究人员希望验证这些磁化作用是由磁黄铁矿携带的假设。磁黄铁矿表现出许多随温度变化的诊断磁性。除了将在FIU古地磁实验室进行的标准岩石磁性测量外，我们还将在明尼苏达大学岩石磁性研究所进行磁滞和随温度变化的测量。在进行这些非破坏性测量后，PI将抛光钻石以暴露包裹体，并使用微观探针分析检查矿物学。这些实验将确定观察到的磁化作用是由磁黄铁矿携带还是由其他铁/镍硫化物携带。确定导致包裹体强烈磁化的矿物(S)可能会为使用钻石从地球历史的关键时期获得古强度数据，以及研究这些矿物在钻石内部高压下的磁性提供令人兴奋的可能性。佛罗里达国际大学的古新学项目一直在吸引本科生和研究生参与其正在进行的研究项目。佛罗里达国际大学是一所以西班牙裔为主的大学，对FIU古地磁学项目的支持有助于让地球科学中代表性不足的群体参与进来。

This is a pilot study to take advantage of the presence of pyrrhotite inclusions in diamonds as: 1) a potential recorder of the strength of Earth's magnetic field and 2) to test hypotheses based on the magnetic properties of pyrrhotite at high pressure. The PI's initial results are startling in that the inclusions in these diamonds are strongly magnetic and, perhaps more surprising, that they are stably magnetized. The researchers hope to test the hypothesis that these magnetizations are carried by pyrrhotite. Pyrrhotite exhibits a number of diagnostic magnetic properties that vary with temperature. In addition to standard rock magnetic measurements that will be carried out in the FIU paleomagnetism laboratory, we will conduct hysteresis and temperature-dependent measurements at the Institute for Rock Magnetism at the University of Minnesota. After conducting these non-destructive measurements, the PI will polish the diamonds to expose the inclusions and examine the mineralogy using microprobe analyses. These experiments will determine whether the observed magnetizations are carried by pyrrhotite or by other iron/nickel sulfides. Identifying the mineral(s) responsible for the strong magnetizations of theseinclusions may open up exciting possibilities for using diamonds to obtain paleointensity data from critical intervals of Earth history, and for the study of the magnetic properties of these minerals at the high pressures within diamonds.The paleomanetism program at Florida International University has consistently involved both undergraduate and graduate students in its ongoing research programs. Florida International University is a predominantly Hispanic university, and support of the paleomagnetism program at FIU helps to involve under- represented groups in the Earth Sciences.