Grant: Discovery Grants Program - Individual

Recent direct observations have demonstrated that the geomagnetic field has undergone dramatic changes over the last century. This is best illustrated by changes in the position of the North Magnetic Pole (NMP) and the rapid decline of the dipole field (i.e, the main component of Earth's magnetic field). The NMP, restricted to the Canadian Arctic during historical times, has recently moved into the Arctic Ocean. In addition, the recent migration of the NMP occurs between two important areas of observed geomagnetic fluxes in N. America and Siberia. The role of these geomagnetic flux lobes in driving Holocene geomagnetic variability is currently unknown. Similarly, recent satellite observations in the S. Hemisphere and geomagnetic models reveal an important magnetic anomaly developed over the last centuries in the S. Hemisphere. These recent spectacular changes lead to the formulation of the following questions: "Are we in the initial stages of a large-scale geomagnetic change, or even a reversal?" and "are these changes associated with the dynamics of the N. American and Siberian flux lobes?". To answer these fundamental questions, the historical record must first be placed into a longer geological context. The overarching goal of this research program is to transform our current understanding of geomagnetic changes by investigating the magnetic record as a whole from its acquisition to its impact on the modulation of cosmic rays. The objectives of this research program are ambitious and twofold: scientific and methodological. At the scientific level, the long-term goal is to determine the high frequency dynamics of the geomagnetic field during the Holocene in both hemispheres with a special emphasis on abrupt changes. At the methodological level, the long-term goal is to develop paleomagnetic regional master curves, allowing the dating and synchronization of lacustrine, marine and ice core records. This research program will provide the first large-scale study of Holocene geomagnetic field dynamics from the Arctic to Antarctica. In addition, it will investigate geomagnetic field variability at a temporal resolution that will: 1) enable testing of hypotheses developed from the historical geomagnetic record, 2) yield invaluable data for geodynamo modelling, and 3) place the current dramatic collapse and migration of the NMP into a detailed geological context. The proposed research will also provide novel data to enhance our understanding of Sun/Earth interactions to help decipher the influence of the geomagnetic field on the production rate of cosmogenic isotopes, with practical implications for dating, space weather, telecommunications, human health and climate. Finally, as a by-product of the analysis of numerous sediment cores, this research program will allow the development of climate change and natural hazard proxies, in addition to the further assessment of the impact of lithological changes on the NRM acquisition process.