Pleistocene Paleointensity Record of Aleutian Island Volcanics

这个项目是一项地质调查，旨在加深我们对地球古代磁场的了解。PI正在与阿拉斯加安克雷奇的美国地质调查局(USGS)合作，从阿留申群岛链中的塔纳加岛收集熔岩流样本。对这些熔岩进行的磁性实验将使研究小组能够恢复阿拉斯加地球古代磁场的强度，并利用这些信息来评估过去50万年来地球磁场的平均行为。古地磁数据(如作为该项目的一部分收集的古强度信息)在许多地质和地球物理应用中发挥着重要作用，例如：进行板块构造重建，确定岩石形成的时代和构造事件的时间，以及发展地球内部的模型。该项目将首次对阿拉斯加熔岩流进行高质量的古强度研究，并将使研究人员能够更好地了解地球磁场在北部高纬度地区的行为。对古代地磁场结构的有效分析需要收集地理和时间上分布的全球古地磁数据。大多数已发表的古地磁数据来自中纬度，针对赤道和高纬度(50°)地区的研究相对较少。对在线魔术古地磁数据库(http://earthreg.org/MAGIC))的搜索显示，只有四项研究来自阿拉斯加，而且没有一项提供任何古强度数据。该项目将是该地区第一个高质量的古强度研究。PI和学生们将从来自塔纳加岛的35个更新世时代的熔岩流中采样火山物质。美国地质调查局的研究人员使用40Ar/39Ar地质年代学方法对所有熔岩流进行了测年。古强度实验将在所有熔岩上进行，结果将与南北半球的其他高纬度数据集进行比较。对我们强度结果的评估将使我们能够对阿拉斯加地磁场的长期区域行为以及全球磁场随时间的变化有新的见解。

This project is a geologic investigation aimed at furthering our understanding of the Earth's ancient magnetic field. The PI is working with the U.S. Geological Survey (USGS) in Anchorage, Alaska to collect lava flow samples from Tanaga Island in the Aleutian Island chain. Magnetic experiments on these lavas will allow the team to recover the strength of the Earth's ancient magnetic field in Alaska and use that information to evaluate the average behavior of the geomagnetic field over the last 500 thousand years. Paleomagnetic data (such as the paleointensity information collected as part of this project) play an important role in many geologic and geophysical applications, such as: performing plate tectonic reconstructions, determining the age of rock formations and timing of tectonic events, and developing models of the Earth's interior. This project will present the first high-quality paleointensity study of Alaskan lava flows, and will allow researchers to better understand how the geomagnetic field behaves at high northern latitudes. Effective analysis of ancient geomagnetic field structures requires the collection of global paleomagnetic data that are geographically and temporally distributed. Most published paleomagnetic data are from mid-latitudes, with relatively few studies targeting localities at equatorial and high latitudes ( 50°). A search of the online MagIC paleomagnetic database (http://earthreg.org/MAGIC) shows that only four studies are from Alaska, and none of them present any paleointensity data. This project will be the first high-quality paleointensity study in the region. The PI and students will sample volcanic material from 35 Pleistocene-age lava flows from Tanaga Island. All lava flows have been dated using 40Ar/39Ar geochronology methods by researchers with the U.S. Geological Survey. Paleointensity experiments will be conducted on all lavas, and the results will be compared to other high latitude data sets in northern and southern hemispheres. Evaluation of our intensity results will allow for new insights into the long-term regional behavior of the geomagnetic field in Alaska and the variability of the global field over time.