Collaborative Research: The Holocene paleomagnetic record of the Arctic

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。该奖项将支持重建北极全新世古地磁记录，并调查与区域气候的联系。该项目的中心重点是从阿拉斯加西北和东北部以及加拿大班克斯岛和维多利亚岛的麦肯齐三角洲的湖泊中连续采集3至5米长的沉积物岩心。将从四个地点的两个类似湖泊系统中回收多个岩心。这些岩心将成为一系列分析技术的对象，包括磁性、岩石地层学、地球化学和生物测量。选定的研究地点将提供贯穿全新世的记录，最远可追溯到20 ka，提供迄今为止最长的高分辨率北极古地磁记录。年代学将主要通过使用现代AMS C-14技术的放射性碳测年得出。将使用一系列方法记录该地区的气候历史，包括环境磁学、地球化学、扫描XRF、生物硅和加拿大合作者的一系列生物气候代用指标。通过对每个湖泊的多个岩心进行交变磁场退磁，对古地磁和环境磁记录进行研究。这项研究的“智力价值”在于开发一套新的全新世古地磁观测资料，这套资料将在空间和时间上证实和扩展以前的北极古地磁观测资料，并补充正在进行的北极和全球全新世古地磁活动。扩展的北极古地磁记录将允许直接与冰岛的海洋记录以及目前正在阿拉斯加湾、北冰洋和巴芬湾开发的海洋记录进行比较。这些新的记录将允许重建全新世北极（可能还有北极以外）的古地磁记录，为检验地磁假说提供必要的限制，有助于北极磁性地层网络的持续发展，以促进海洋和陆地古记录的定年，并对地磁场是否在气候系统中发挥作用提供了新的限制。这项研究的“更广泛的影响”与科学和教育成果有关。该研究产生的数据，结合第一阶段和其他已发表研究的结果，将提供北极周围180°的古地磁视角，记录过去的变化，并提供对未来行为的古约束和北磁极持续运动的影响。这些数据还将有助于区分地磁与太阳控制对地球宇宙射线通量和宇宙成因同位素产生的作用，对电信、人类健康、全球生态系统和气候有实际影响。数据将提供给magIC、sedDB和NOAA古气候数据库，并用于补充正在进行的关于数据很少的区域的全球地磁场球谐研究。这项研究将支持本科生和研究生的培训，研究结果将通过网站、公开讲座和K-12教学倡议广泛传播给公众。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This award will support a reconstruction of the Holocene paleomagnetic record of the Arctic and investigate linkages with regional climate. The central focus of this project is to recover continuous 3 to 5 m-long sediment cores from lakes in NW and NE Alaska, and the Mackenzie Delta, Banks Island and Victoria Island, Canada. Multiple cores from two similar lake systems at each of the four locations will be recovered. The cores will be the subject of a series of analytical techniques including magnetic, lithostratigraphic, geochemical and biological measurements. The sites selected for study will provide records that extend through the Holocene back as far as 20 ka providing the longest high-resolution Arctic paleomagnetic records to date. Chronologies will be primarily derived by radiocarbon dating using modern AMS C-14 techniques. A series of methods will be used to document the climate history of the region including environmental magnetism, geochemistry, scanning XRF, biogenic silica and a host of biological climate proxies with Canadian collaborators. The paleomagnetic and environmental magnetic records will be studied on multiple cores from each lake by alternating field demagnetization of u-channel samples.The 'Intellectual Merit' of the study lies in the development of a new set of Holocene paleomagnetic observations that will confirm and expand, spatially and temporally, upon previous Arctic paleomagnetic observations and supplement ongoing Arctic and global Holocene paleomagnetic initiatives. The extended Arctic paleomagnetic record will permit direct comparison to marine records from Iceland and those now being developed in the Gulf of Alaska and the Arctic Ocean and Baffin Bay. These new records will permit reconstruction of the Holocene (and possibly beyond) paleomagnetic record of the Arctic, provide constraints necessary to test geomagnetic hypotheses, contribute to the continuing development of an Arctic magneto-stratigraphic network to facilitate dating of marine and terrestrial paleorecords, and provide new constraints on whether the geomagnetic field has a role in the climate system.The 'Broader Impacts' of the study relate to scientific and educational outcomes. Data generated from the study, when combined with results from Phase I and other published studies, will provide a 180° paleomagnetic perspective around the Arctic, documenting past changes and providing paleo-constraints on the future behavior and impacts of the ongoing motion of the north magnetic pole. The data will also help to differentiate the contributions of geomagnetic versus solar control on terrestrial cosmic ray flux and cosmogenic isotope production with practical implications for telecommunications, human health, global ecosystems and climate. Data will be contributed to magIC, sedDB and NOAA paleoclimate databases and used to supplement ongoing spherical harmonic studies of the global geomagnetic field from a region with little data. The study will support the training of undergraduate and graduate students and the results will be widely communicated to the general public through Web sites, public lectures and K-12 teaching initiatives.