Late Quaternary geomagnetic field dynamics and abrupt changes

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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. Direct observations reveal that the migration of the NMP has increased dramatically since the early 1970's from 9 km/yr to 41 km/yr and to almost 60 km/yr in 2003, whereas the annual rate of change in intensity measured at the Resolute Bay geomagnetic observatory has increased from about 10 nT/yr to almost 70 nT/yr over the last 50 years. These 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 if so, "What are the causes (in Earth's core) and consequences (to Earth's environment) of a large scale geomagnetic change?" To answer these fundamental questions,the historical record must first be placed into a longer geological context. The long-term goal of this research program is thus to determine the high frequency dynamics of the geomagnetic field during the Late Quaternary with a special emphasis on abrupt changes and their possible influence on climate. This research program will provide the first large-scale study of geomagnetic field dynamics in the Arctic. In addition, by selecting coring sites with very high sediment accumulation rates, the proposed research will investigate geomagnetic field variability at a temporal resolution that is just beginning to be explored, the centennial to millennial timescales. These observations 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. Finally, exploring the potential linkages between climate change and geomagnetic field morphology deserves special attention at this time of rapid climatic change as no current numerical climate model accounts for the possible influence of cosmic rays or the geomagnetic field on climate.