The strength of the Earth's magnetic field is important to modern society because it protects Earth and its communication satellites from harmful levels of solar radiation. During periods when the Earth's relative magnetic field strength drops (e.g., during solar flares), increased amounts of solar radiation are allowed to penetrate further into the upper atmosphere causing damage to satellites and interfering with shortwave radio communication. For this reason, it is important to understand the natural short-term variability of the Earth's magnetic field. Records of past geomagnetic field behavior are well-preserved by magnetic minerals within volcanic and sedimentary rocks. Although scientists have long used these records to study the long-term history of magnetic polarity reversals, records of more short-lived geomagnetic instabilities are poorly resolved in time, typically incomplete, and lacking in detail. Developing enhanced, global records with precise age control is essential to identifying common trends during and leading to magnetic field instability.
The research supported by this grant aims to produce the most globally complete record of unstable geomagnetic field behavior to date. We plan to integrate magnetic records collected from volcanic and sedimentary rocks from around the world in order to compile a chronologically calibrated, continuous full-vector record of geomagnetic field behavior during the Réunion geomagnetic event, which occurred roughly two million years ago. This research will allow us to address several fundamental questions: How quickly to geomagnetic instabilities manifest themselves? Do geomagnetic instabilities occur synchronously around the world, or do they affect some geographic regions longer and more severely than others? How weak is the Earth's magnetic field during an instability event? In addition to helping resolve these questions, the data generated during this research will be key to future efforts aimed at modeling the complete behavior of the Earth?s magnetic field and will refine the magnetostratigraphy of the Lower Quaternary, thereby improving the correlation of strata on a global scale.
