One of the prime objectives of IODP Expedition 318, January to March 2010 (Wellington to Hobart) was to obtain an ultra high resolution record of the Holocene from drilling in the Adelie Basin. The Adelie Basin contains a 190 m thick sequence of diatomaceous ooze overlying a glacial diamict with an age of about 11 ka. Sediments obtained at Site U1357 reveal an ultra-high resolution record with the first annually resolved time series of oceanographic and climatic variability derived from the Southern ocean. Site U1357 was triple cored. Hole U1357A was split and processed during the expedition while Holes U1357B and C were sealed in nitrogen flushed bags and only split during the sampling party (June 27, 2010 - July 3, 2010). Data obtained from shipboard measurements of the archive half of U1357A documented an unrivaled record of secular variation (SV) of the geomagnetic field, which promises not only an unprecedented SV record but also will provide critical constraints for hole to hole correlation. During post-cruise sampling we bolstered our confidence in the reliability of this unique record, but also discovered that the magnetic mineralogy degrades extremely rapidly after exposure to air. While the discrete samples have been placed in nitrogen flushed bags for transport, immediate measurement is urgently required. Also, because the magnetic mineralogy is likely to be quite unusual (for example biogenic iron sulfides), it must also be characterized prior to as well as after oxidation. We therefore request funding via the RAPID funding mechanism. Support for the remaining Expedition 318 paleomagnetic efforts will be requested using the usual EOR mechanism.
One of the prime objectives of IODP Expedition 318, January -- March 2010 (Wellington -- Hobart) was to obtain an ultra high resolution record of for the last 10,000 years from drilling in the Adelie Basin, off the Antarctic coast. The basin is filled with nearly 200 meters ooze overlying a deposit of glacial degris about 11,000 years ole. Sediments obtained at our drill site reveal the first annually resolved time series of oceanographic and climatic variability derived from the Southern ocean with over 2 cm deposited every year. IODP Drill Site U1357 (66S, 144E), was triple cored. The first hole, U1357A, was split and processed during the expedition while Holes U1357B and C were sealed in nitrogen flushed bags and only split during the sampling party (June 27, 2010 - July 3, 2010). During the expedition, we measured the split core halves in a special magnetometer which gave us a record of the magnetic direction and strength of the sediments, prior to sub-sampling. These data documented an unrivaled record of the ever changing magnetic field of the Earth (secular variation or SV). After post-cruise sampling we bolstered our confidence in the reliability of this unique record, producing a replicate record of the first hole, determined with the more reliable measurements made on the discrete samples in the Scripps Paleomagnetic Laboratory. The two records can be correlated with a high degree of confidence. However, at the present time, the results are waiting age calibration with radiocarbon dates from two of the three holes. By combining radiocarbon dates with the SV record, we will not only have a robust hole-to-hole correlation, but also have the best dated, highest resolution record of geomagnetic field behavior from the Southern Hemisphere yet produced.
