Mapping and Modeling Sources of Natural Remanent Magnetization in the Microcline–Sillimanite Gneiss, Northwest Adirondack Mountains: Implications for Crustal Magnetism

Distinct crustal remanent magnetic anomalies are a strong indicator of rocks with stable natural magnetization (NRM) carriers. The latter able to store information on the history rock over long geological periods, and can therefore be used for variety applications in field paleomagnetism magnetism. Typically, paleomagnetic rock-magnetic studies rely bulk properties. With advent high-resolution magnetometric scanning techniques, it is now possible map sources at mineral scale, identify different carriers, analyze effect geometry, microstructures, composition their response. We investigate stability discrete microcline–sillimanite gneiss sample from Russell Belt NRM, by before, after alternating demagnetization 100 mT. quantified changes intensity direction inverting scan data. Here, we confirm that exsolved titanohematite ilmenite lamellae major source magnetization, coexisting multidomain hematite grains contribute little or anomalies. microstructures control local properties scale. Magnetic modeling results suggest consistent average before both grain thin section decrease ≈30%. Results previous measurements likelihood use techniques future high.