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可靠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。高纬度的北太平洋取样不足，了解不足，充满争议。本研究使用的材料来自阿拉斯加湾综合海洋钻探计划（IODP）第341次远征期间收集的新的深海沉积物岩心，将提供第一批高质量、高分辨率的同位素和磁场数据，以了解该地区对全球海洋和冰川动力学、生物地球化学循环和地球磁场基本特性的贡献。这项研究的结果将引起公众的浓厚兴趣，例如，将地球磁场的变化与宇宙射线的屏蔽联系起来，这一现象影响到依赖与北极光有关的旅游业的全球电信和企业。此外，这项工作的结果可能对环境和生物暴露于辐射有影响。阿拉斯加湾的高沉积率是由一个冰川覆盖的构造活动边缘支撑的，这确保了几乎连续不断地提供细粒度的成岩物质。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化石的保存。这种快速积累的沉积物只有通过钻探才能获得。IODP远征341（南阿拉斯加边缘构造、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341考点建立可靠的高分辨率年代地层学。U1417和U1418的主要焦点是过去~ 1 Ma的亚千年分辨率；并将重点研究U1419地点亚世纪分辨率的末次冰期旋回（~0-50 ka）。

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.