Northern North Atlantic Paleomagnetic Synthesis


The northern North Atlantic region records a rich history of variability that is reflected in sediment magnetic properties and the paleo-geomagnetic record. Variations in ice sheets and ocean circulation influence regional sedimentation, while the morphology of the geomagnetic field influence the paleomagnetic record.

Our project in the northern North Atlantic focuses on the development of a Holocene synthesis of paleomagnetic and environmental magnetic data with the aim of constraining the space/time variability of this extremely rich record to improve our understanding of climate, environment and the geomagnetic dynamics of the region. Sediments from the northern North Atlantic are optimal for such a study because magnetic properties are suitable for high quality environmental and paleomagnetic observations and the abundance of tephras and carbonate facilitate well constrained chronologies.

We are developing paleomagnetic records from this region that are among the highest resolution, best dated and most accurate from anywhere on the globe. The importance of this record reflects the quality of the chronology and the preservation of abrupt, high amplitude geomagnetic features never previously observed.

Figure 1. Intercalibration of the N. Iceland shelf core MD99-2269 paleomagnetic record and the Icelandic tephra chronology record, compared with global spherical harmonic model predictions. Note, the significantly greater amplitude and higher rate of change found in the actual data than those derived from model predictions.

Figure 2. The time averaged vertical component of magnetic field (z) at the core-mantle boundary (Gubbins et. al., 2006) showing the unique geomagnetic horseshoe structure that surrounds the North Atlantic. Note the regions of concentrated flux over North America and Siberia known as flux lobes.