CSEDI: Collaborative Research: Paleomagnetism, the Geodynamo and Core-Mantle Interactions

建议在三个时间尺度上，结合地球动力学、地球动力学建模和古地磁，开展地幔对地球动力学影响的协同研究。首先，通过观察过去的500万年，发电机在一段时间内的长时间尺度行为，在这段时间内，时间平均场和古长期变化都可以确定，古地磁将被检查。此外，在这个时间尺度上，最下面的地幔与使用地震层析成像成像的地幔基本没有变化，因此可以使用现代地幔层析成像图像。其次，将研究地磁倒转频率的变化，主要集中在白垩纪正超时纪到现在这一时期，包括地幔底部的地幔柱形成对磁场中磁通量反转斑块发生的影响。第三，将对数亿年时间尺度上的极长期磁场变化进行初步调查。这项工作将包括对现有的古地磁测量数据进行统计重新分析，以评估哪种地球动力学实验将与理解这种长期变化有关。发电机建模和地球动力学建模将在哈佛进行；该提案的古地磁方面，包括数据汇编、分析和现场建模，将在斯克里普斯海洋学研究所进行。这项工作将主要以电子方式在两所院校之间协调，并辅以两所院校之间的访问和短期学生交换。

Bloxham Constable It is proposed to undertake a collaborative study of mantle influences on the geodynamo, combining geodynamics, geodynamo modeling and paleomagnetism, focusing on three timescales. First, by looking at the last 5 million years the long timescale behavior of the dynamo over a period for which both the time averaged field and the paleosecular variation can be determined paleomagnetically will be examined. Furthermore, on this timescale the lowermost mantle is essentially unchanged from that which is imaged using seismic tomography, so modern tomographic images of the mantle can be used. Second, changes in reversal frequency, concentrating on the period from the Cretaceous Normal Superchron to the present day will be examined, including the effect of plume formation at the base of the mantle on the occurrence of reverse flux patches in the magnetic field. Third, preliminary investigations will be conducted on the very long-term changes in the magnetic field occurring over timescales of several hundred million years. This work will involve a statistical re-analysis of the available paleomagnetic measurements to assess what kinds of geodynamo experiments will be relevant to understanding such long-term changes. The dynamo modeling and geodynamical modeling will be performed at Harvard; the paleomagnetic aspects of the proposal, involving data compilation, analysis, and field modeling will be performed at Scripps Institution of Oceanography. The work will be coordinated between the two institutions primarily by electronic means, supplemented by visits and short-term exchange of students between the institutions.