Linking magnetic and isotopic data from Gulf of Alaska deep-sea cores: understanding the region's contribution to global oceanographic variability and the earth's magnetic field

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Developing a robust timescale of geologic events in key geographic areas is essential for understanding the global system and its record of change. The high-latitude North Pacific is under-sampled, poorly understood, and filled with controversy. This study, using material from new deep-sea sediment cores collected during Integrated Ocean Drilling Program (IODP) Expedition 341 in the Gulf of Alaska, will provide the first high-quality, high-resolution isotopic and magnetic data needed to understand the contribution of this region to global oceanographic and glacial dynamics, biogeochemical cycles, and fundamental properties of the earth's magnetic field. Results of this study will be of keen interest to the public, for example, by relating variations in the earth's magnetic field to shielding of cosmic rays, a phenomenon which impacts global telecommunications and businesses that rely on tourism related to the Aurora Borealis. In addition, results from this work could have implications for environmental and biological exposure to radiation. Great sedimentation rates in the Gulf of Alaska are supported by a glaciated, tectonically active margin that ensures an almost continuous supply of fine-grained lithogenic material. These high sedimentation rates support a strong record of paleomagnetic variations and enhance preservation of calcareous microfossils suitable for isotopic analysis. Such rapidly accumulating sediments are only accessible through drilling. Three sites (U1417, U1418, U1419) drilled during IODP Expedition 341 (Southern Alaska Margin Tectonic, Climate and Sedimentation) provide, for the first time, the high-quality materials needed to assess globally important climatic, glacial, and paleomagnetic variability in the North Pacific. The PIs will use a tandem stable isotopic and paleomagnetic approach to develop robust, high-resolution chronostratigraphies in the Expedition 341 sites. The primary focus is on the past ~ 1 Ma, at submillenial resolution for sites U1417 and U1418; and will focus on the last glacial cycle (~0-50 ka) at subcentury resolution for site U1419.