Paleomagnetic Records from the Gulf of Alaska

Recent observations from high-resolution sedimentary and archeomagnetic records indicate that the paleo-geomagnetic field displays variance on sub-millennial and even sub-centennial time scales. The majority of these observations are concentrated in the Atlantic sector of the Northern Hemisphere, while the under-sampled Pacific is thought to have subdued geomagnetic variability. To better understand this spatial variability, our lab is developing well-dated, high-resolution paleomagnetic records on sediment cores collected from the fjords, continental shelf, slope, and rise of the Gulf of Alaska during R/V Maurice Ewing Cruise EW0408.

The diversity of sites occupied during R/V Maurice Ewing Cruise EW0408 allows us to address questions ranging from the physical, chemical, and biological influences on magnetic acquisition, to establishing the scale of geomagnetic regionality. Detailed chronologies for these cores are being developed via the use of precise accelerator AMSĀ 14C dating of ultra-small samples. This technique, developed at the Keck AMS Laboratory at UC Irvine, reduces required sample sizes by an order of magnitude, opening new opportunities for precise dating.

 

Map showing locations of cores 79 and 85JC, that are being studied for their paleomagnetic record.