RUI: Paleomagnetic Study of the Matuyama-Brunhes Reversal from Dated Lava Sequences on Tahiti, French Polynesia

9627927霍夫曼 PI建议继续研究地球最近的磁极反转，塔希提岛熔岩中的Matuyama-Brunhes（M-B），并利用来自世界各地其他熔岩流和可靠沉积序列的可用数据集将此记录整合到M-B反转过程的全球模型中。 地磁场逆转的研究正在迅速发展的复杂程度，最近成功的三维计算机辅助模拟发电机的过程。 这些进展使得从古地磁记录中了解地球表面的实际磁场行为变得至关重要。 从地球仪周围4个地点的熔岩中获得的Matuyama-Brunhes反转的现有数据和最近对这些熔岩的40 Ar/39 Ar年龄测定支持虚拟地磁极（VGP）沿沿着由南向北的地理轨迹迁移的单一过程，而是一个涉及一系列发电机事件和长期存在的场配置的更复杂的过程。 PI要求在未来两年继续资助他的工作，以（1）对记录反转的几个平行剖面进行采样，（2）进一步开发塔希提岛经历的反转过程的复合时序图，（3）尽可能使用新修改的多样本技术对这些岩石进行古强度测定，（4）利用现有的沉积物资料，建立全球性的Matuyama-Brunhes反转过程模式。 这个RUI将继续涉及加州理工学院的一些物理专业本科生。

9627927 Hoffman The PI proposes to continue his studies of the earth's most recent magnetic polarity reversal, Matuyama-Brunhes (M-B) in lavas in Tahiti, and to integrate this record into a global model of the M-B reversal process using available data sets from other lava flows and reliable sedimentary sequences worldwide. The study of geomagnetic field reversals is rapidly evolving in its degree of sophistication with recent successful 3D computer-assisted simulations of the dynamo process. These advances make essential an understanding of actual field behavior at Earth's surface obtained from the paleomagnetic record. Available data of the Matuyama-Brunhes reversal obtained from lavas from 4 sites about the globe and recent 40Ar/39Ar age determinations on these lavas support not a singular process in which the virtual geomagnetic pole (VGP) migrates along a south-to-north geographic track, but rather a more complicated process involving a series of dynamo events and long-standing field configurations. The PI requests funding to continue his effort over the next two years to (1) sample several parallel sections recording the reversal, (2) develop further a composite chronological picture of the reversal process as experienced on Tahiti, (3) perform paleointensity determinations on these rocks whenever possible using a newly-modified multispecimen technique, and (4) construct a global model for the Matuyama-Brunhes reversal process using available data from sediments. This RUI will continue to involve a number of undergraduate physics majors at California Polytechnic.