Magnetostratigraphy and Rock Magnetism of Expedition 318 Sediments

智力成就IODP考察队318年1月？2010年3月(惠灵顿？(2)确定从湿冰期到冷冰期的可能转变的性质和年龄；3)获得新第三纪晚期和第四纪南极气候变化的高分辨率记录；4)通过在Ad’elie盆地的钻探获得全新世的超高分辨率记录。IODP探险队318钻探了7个地点，并回收了&amp；#8764；2500米下始新世至全新世沉积物。318远征队的一个重要目标是记录沉积物和沉积断裂的年龄。初步的磁地层学数据为南大洋的生物地层学提供了关键的限制和校准，在那里直接校准非常缺乏。例如，在ODP Leg 189期间钻探的塔斯马尼亚共轭边缘的岩心恢复了类似年龄的沉积物，但到目前为止，古近系部分的磁地地学不足以校准地质时间尺度。318远征队沉积物的磁性结构、矿物学和粒度信息为这一独特的沉积序列中记录的环境变化提供了有趣的线索。IODP 318探险队的另一个主要目标是通过在Ad ' elie盆地的钻探获得全新世的超高分辨率记录。Ad ' elie盆地是一个190米厚的硅藻软泥序列，覆盖在一个年龄为8764岁的冰川上。11 ka。站点U1357揭示了第一个来自南大洋的海洋和气候变率的年度分解时间序列。从船上对U1357A一半存档的测量数据中获得的数据记录了无与伦比的地磁场长期变化（SV）记录，这不仅保证了前所未有的SV记录，而且将为孔间相关性提供关键约束。该提案要求为318远征队钻探获得的材料的古地磁和岩石地磁分析提供资金。它还寻求适度的资金，用于对ODP第189阶段钻探的岩心进行取样和分析，这些岩心存放在日本高知储存库中。广泛的影响由氧同位素值汇编揭示的新生代冰期历史及其与推断的大气CO2的关系具有重大的科学意义。南极冰冻圈在全球气候系统中发挥着关键作用，因此其历史在当前的气候变化辩论中发挥着重要作用。拟议的工作对于将威尔克斯陆沉积物置于高分辨率年代地层格架中至关重要。全球古长期变化模型对于探索地磁场的行为非常有用，可以作为古地磁测年的工具，也可以作为评估地磁场对放射性碳产生控制的手段。尽管有广泛的用途，但这些模型只能与它们所依据的数据一样好，到目前为止，来自南半球的记录很少。此外，迄今为止没有获得的记录具有U1357站点可实现的分辨率。因此，本文的工作有可能大大改进古长期变化模型。该提案还将有助于培养博士后学者杉崎齐子博士。她作为一名船上的古地磁学家参加了第318远征队，尽管她接受的训练是光激发光。她花了几个月的时间专注于古地磁研究，并参加了Scripps提供的在线古地磁课程（http://magician.ucsd.edu/∼ltauxe/sio247），她决定在Scripps的古地磁实验室继续她的博士后教育。PI以开展短期课程、免费提供古磁学基本要素教材、在线免费提供课程以及开放PmagPy古磁学软件包等方式向更广泛的社区开展拓展工作而闻名。这项建议将为这些教育/外联活动提供部分支助

Intellectual MeritThe overall objectives of IODP Expedition 318, January ? March 2010 (Wellington ? Hobart) were: 1) to determine the timing of the arrival of ice at the Wilkes Land margin, 2) to determine the nature and age of possible transitions from a wet-based to a cold based glacial regime, 3) to obtain a high-resolution record of Antarctic climate variability during the late Neogene and Quaternary, and 4) to obtain an ultra high resolution record of the Holocene from drilling in the Ad´elie Basin. IODP Expedition 318 drilled seven sites and recovered ∼2500 m of Lower Eocene to Holocene sediments. A critical aspect of the stated goals of Expedition 318 is documenting the age of the sediments and sedimentary hiatuses. Preliminary magnetostratigraphic data provide crucial constraints as well as calibration for the biostratigraphies in the Southern Ocean, where direct calibration is notably scarce. For example, cores from the conjugate margin of Tasmania drilled during ODP Leg 189 recovered sediments of similar age, but the magnetic stratigraphy for the Paleogene portion so far is inadequate for the purposes of calibrating the geological time scale. Magnetic fabrics, mineralogy and grain size information from Expedition 318 sediments provide intriguing clues to environmental changes recorded in this unique sedimentary sequence. Another prime objectives of IODP Expedition 318 was to obtain an ultra high resolution record of the Holocene from drilling in the Ad´elie Basin, a 190 m thick sequence of diatomaceous ooze overlying a glacial diamict with an age of ∼11 ka. Site U1357 revealsh the first annually resolved time series of oceanographic and climatic variability derived from the Southern ocean. 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. This proposal requests funds for the paleomagnetic and rock magnetic analyses of material obtained from Expedition 318 drilling. It also seeks modest funding for sampling and analysis of cores drilled during ODP Leg 189 and housed in the Kochi Repository in Japan.Broader ImpactsThe history of Cenozoic glaciation as revealed by compilations of oxygen isotopic values and its relationship to inferred atmospheric CO2 is of major scientific interest. The Antarctic cryosphere plays a key role in the global climate system and its history therefore plays a role in the current climate change debate. The proposed work is essential for placing the Wilkes Land sediments into a high resolution chronostratigraphic framework. Global paleosecular variation models are extremely useful for exploring the behavior of the geomagnetic field, as a dating tool for archeomagnetism and as a means for assessing the control of the geomagnetic field on radiocarbon production. Despite broad utility, the models are only as good as the data from which they are derived and as of now there are very few records from the southern hemisphere. Moreover, no record obtained to date has the resolution of that achievable at Site U1357. Therefore, the proposed work has the potential to substantially improve the paleosecular variation models. This proposal will also contribute to the education of a post-doctoral scholar, Dr. Saiko Sugisaki. She sailed as a shipboard paleomagnetist on Expedition 318, although her training was in optically stimulated luminescence. Having spent several months intensively engaged in paleomagnetic research, and also having taking the online paleomagnetism class offered through Scripps (http://magician.ucsd.edu/∼ltauxe/sio247), she has decided to continue her education as a post-doctoral scholar in the paleomagnetic laboratory at Scripps. The PI is well known for outreach efforts to the broader community by conducting short courses, by making the textbook Essentials of Paleomagnetism available for free access, by conducting online, free access, courses and by making the PmagPy paleomagnetic software package open source. This proposal will provide partial support for these education/outreach activities