RAPID: Collaborative Research: Paleomagnetic and Rock Magnetic Investigation of IODP Expedition 318 Site U1357 Sediments

IODP 318考察队2010年1月至3月(惠灵顿至霍巴特)的主要目标之一是通过在阿德利盆地的钻探获得全新世的超高分辨率记录。阿德利盆地包含190米厚的硅藻软泥序列，覆盖在冰川直径上，年龄约为11ka。在U1357站获得的沉积物显示了一项超高分辨率记录，其中第一个年度分辨的海洋和气候变异性时间序列来自南大洋。U1357站点是三核的。U1357A孔是在考察期间裂开和加工的，而U1357B和C孔是密封在氮气冲洗袋中的，只有在采样派对(2010年6月27日至2010年7月3日)时才裂开。从U1357A档案一半的船上测量获得的数据记录了无与伦比的地磁场长期变化(SV)记录，这不仅有望创造史无前例的SV记录，还将为孔与孔之间的关联提供关键约束。在巡航后的采样过程中，我们增强了对这一独特记录的可靠性的信心，但也发现，暴露在空气中后，磁性矿物学退化得非常快。虽然离散的样品已放置在氮气冲洗袋中进行运输，但迫切需要立即进行测量。此外，由于磁性矿物学可能非常不寻常(例如生物成因硫化铁)，因此在氧化之前和之后也必须对其进行表征。因此，我们要求通过快速筹资机制提供资金。将使用通常的提高采收率机制，请求对剩余的318次远征古地磁工作提供支持。

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.