University of Minnesota
School of Physics & Astronomy

Physics and Astronomy Calendar

Friday, May 8th 2015
Speaker: Josh Feinberg, U Minnesota, Earth Sciences
Subject: "Shining a Light Into the Dark: Using Cave Deposits to Illuminate Fine-Scale of the Geomagnetic Behavior

Cave deposits, such as stalagmites and stalactites, record the direction
and strength of the Earth's magnetic field as they grow. These geologic
materials offer a new source of information about the behavior of the
Earth's geodynamo. Speleothems record their magnetizations on seasonal
timescales, they are are not affected by the post-depositional processes
that effect marine and lake records, and can be dated with high precision using U-Th techniques. Recent improvements in the sensitivity of magnetic instrumentation and spatial resolution allow geophysicists to leverage speleothems as high-resolution paleomagnetic recorders. Modern studies enable us to resolve short-term geomagnetic variability, and characterize events such as geomagnetic reversals and excursions at an unprecedented scale.

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