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

在关键地理区域建立一个强大的地质事件时间尺度对于理解全球系统及其变化记录至关重要。北太平洋高纬度地区采样不足，了解甚少，充满争议。这项研究使用了在阿拉斯加湾综合大洋钻探计划（IODP）第341次考察期间收集的新深海沉积物岩心材料，将提供了解该地区对全球海洋学和冰川动力学，地球化学循环以及地球磁场基本特性的贡献所需的第一个高质量，高分辨率的同位素和磁性数据。这项研究的结果将引起公众的浓厚兴趣，例如，通过将地球磁场的变化与宇宙射线的屏蔽联系起来，这种现象影响到依赖与北极光有关的旅游业的全球电信和商业。此外，这项工作的结果可能对环境和生物暴露于辐射产生影响。阿拉斯加湾的巨大沉积速率得到了冰川作用的支持，构造活动边缘确保了细粒成岩物质的几乎连续供应。这些高沉积速率支持了古地磁变化的强有力记录，并加强了适合同位素分析的钙质微体化石的保存。这种快速积累的沉积物只能通过钻探获得。在IODP 341（阿拉斯加南部边缘构造，气候和沉积）期间钻探的三个地点（U1417，U1418，U1419）首次提供了评估北太平洋全球重要气候，冰川和古地磁变化所需的高质量材料。PI将使用串联稳定同位素和古地磁方法在远征341站点中开发强大的高分辨率年代地层学。主要重点是过去的~ 1 Ma，在亚千年分辨率的站点U1417和U1418;并将重点放在末次冰期循环（~0-50 ka）在亚世纪分辨率的站点U1419。

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.