RUI: Testing Models of Climate-Induced Geomagnetic Field Behavior with a Record of Pleistocene Paleomagnetic Directions

本研究的主要重点是测试气候诱发的地磁场行为模型，该模型预测全球冰体积的随时间变化与古磁矢量的随时间变化之间的相关性。以前发表的一份来自深海沉积物岩心的18O年更新世变化记录被用来代表过去50万年全球冰量的变化。在这段时间内，磁场的变化由俄勒冈中南部暴露的一个沉积序列的古地磁方向数据记录来表示。在比较两种记录之前，1)进行了详细的采样程序，以提高现有古磁记录的准确性；2)进行了移动窗口交叉光谱分析，以提高年龄控制。后一种方法是三个学术机构正在进行的三种独立的年龄控制方法之一，以改善年龄控制。角色散分析和带通滤波是将改进的古磁记录与18O记录进行比较的两种方法。无论年龄控制方面的改进是否足以验证上述模型，古地磁记录都将对地磁、地层学和构造学的研究作出重大贡献。

The main focus of this study is to test models of climate- induced geomagnetic field behavior which predict a correlation between time-dependent variations in the volume of global ice and time-dependent variations in the paleomagnetic vector. A previously-published record of Pleistocene variations in 18O from deep-sea sediment cores is used to represent changes in global ice volume for last 500,000 years. The variations in the magnetic field during this time interval are represented by a record of paleomagnetic directional data from a sedimentary sequence exposed in south-central Oregon. Prior to comparing the two records 1) a detailed sampling program was conducted to improve the accuracy of the existing paleomagnetic record and 2) a moving-window cross-spectral analysis was conducted to improve the age control. The latter method is one of three independent age control methods underway at three academic institutions to improve the age control. Angular dispersion analysis and band- pass filtering are among the methods used in the comparison between the improved paleomagnetic record and the 18O record. Whether or not the improvements in age control are sufficient to allow the testing of the above models, the paleomagnetic record will contribute significantly to research in geomagnetism, stratigraphy, and tectonics.