HR: 10:20h
AN: U42A-01 INVITED     [Abstracts]
TI: Short-Term Geomagnetic Variability as a Tool for Determining Precise Global Chronologies: Examples From the North Atlantic
AU: * Acton, G
EM: acton@geology.ucdavis.edu
AF: University of California, Davis, Department of Geology, One Shields Avenue, Davis, CA 95616 United States
AB: Short-term variations in the strength and direction of the geomagnetic field have the potential to provide Quaternary chronologies with millennial and sub-millennial resolution. The variations, particularly in the form of large directional swings such as geomagnetic excursions and relative paleointensity highs and lows, can typically be correlated over large regions and, in many cases, worldwide. These attributes, in addition to the relative ease and speed with which high-resolution measurements can be made, provide a means for constructing chronologies that can be used at sites around the globe. When the paleomagnetic records are tied to a variety of climate and environmental proxies - stable isotope, cosmogenic isotope, lithology, sediment color, rock magnetic, and other records - they become a powerful tool for examining the synchroneity of climatic events. Besides being a passive chronologic tool, however, the geomagnetic field may also play a role in climate change or be influenced by such change. Paleomagnetic records from across the North Atlantic reveal the synchroneity of the geomagnetic variability across the region, including the occurrence of multiple geomagnetic excursions during the Brunhes chron (0-780,000 years). Intriguing relationships between the geomagnetic variability and both climate change and orbital forcing suggest a causal link.
DE: 1105 Quaternary geochronology
DE: 1513 Geomagnetic excursions
DE: 1521 Paleointensity
DE: 1522 Paleomagnetic secular variation
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
SC: Union [U]
MN: Fall Meeting 2005