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 these inclusions 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.
