As commercial and military institutions looks to develop alternative navigational systems to global positioning systems satellites, whose function can be compromised by solar storms and by forms of human-made electromagnetic noise, maps of local variations in the Earth’s magnetic field will play an increasingly important strategic role.  Understanding the source of localized magnetic field variations is therefore essential in developing this resource.  Further, as new high-resolution magnetic data become available from the European Space Agency’s SWARM satellite mission, it will be important to understand the exact sources of magnetization in the Earth’s crust and mantle. The goal of this grant was to determine if the uppermost portion of the Earth’s mantle could contribute to long wavelength magnetic anomalies.  Our best view into the mantle is via samples of mantle rock called “xenoliths” that are incorporated into magmatic systems associated with active volcanoes and carried to the surface during eruptions.  This grant allowed researchers from the University of Minnesota (UMN) and Southern Illinois University, Carbondale (SIUC) to collaborate and measure the magnetic properties of a wide survey of mantle xenoliths from around the globe from different tectonic environments.  We found that there are measurable quantities of magnetic minerals in mantle rocks, and that when these magnetic properties are incorporated into models of the thermal structure of the crust and mantle (how temperature varies with depth), that there are certain tectonic environments where the mantle can plausibly contribute to magnetic anomalies as observed by aircraft and satellites.  Regions with depressed geotherms (where there is comparatively little increase in temperature with depth), such as subduction zones, are particularly likely to show magnetic contributions from the uppermost mantle.

In addition to sponsoring a new collaborative relationship between UMN and SIUC, this grant also helped provide training and mentoring experience for three female doctoral students in geophysical methods and electron microscopy. The work completed as part of this grant by the joint UMN and SIUC team was shared via peer-reviewed publications and conference presentations.  The University of Minnesota was involved in the production of three peer-reviewed scientific papers and a multitude of conference papers and presentations. These publications have already garnered the interest of researchers in the geodynamics and remote sensing communities.

Last Modified: 02/21/2016
Modified by: Joshua M Feinberg