Paleomagnetic Studies of Transitional Field Behavior with Emphasis on the Comparison of Different Types of Recordings

过渡场行为的古地磁观测来自各种各样的火成岩和沉积构造。然而，可能没有一种岩石类型具有提供ideaÕ记录的能力，无论是在矢量场变化方面还是在时间精度方面。的确，每一种录音方式似乎都有其自身的优点和局限性。计划中的两项研究不仅有望阐明地磁反转过程，而且还将增强我们对记录保真度与岩石类型之间关系的认识。第一个项目目前正在进行中，涉及实现极性转变，对应于夏威夷莫洛卡火山熔岩的Olduvai正常极性事件的终止。导出的记录完成后，将与从附近深海沉积物中获得的相同转变的公开记录进行严格比较。第二个项目涉及在新西兰北岛Mangapoike河沿岸暴露的快速沉积的海洋沉积物中记录的顺序反转的详细古场行为。该层序与晚中新世有很好的相关性。新西兰南岛的阿卡罗阿火山——这个P.I.之前过渡性实地研究的重点——似乎是与海洋沉积物同时形成的。这种情况提供了一个难得的机会来比较两种不同的古地磁岩石类型的过渡记录。与加州理工学院过去的古地磁项目一样，几名本科生将参与整个拟议的项目，从实地协助到实验室分析。有些人将承担原始研究的一个方面作为他们自己的，并产生一个高级项目。

Paleomagnetic observations of transitional field behavior come from a wide varkety of igneous and sedimentary structures. Yet it may be that no one rock type possesses the capabilities to render ideaÕ recordings, both in terms of vector field changes as well as temporal accuracy. Indeed, each type of recording appears to have its own set of advantages as well as limitations. The two studies planned promise not only to shed light on the geomagnetic reversal process, but also to enhance our knowledge regarding the relationship between record fidelity and rock type. The first project, presently ongoing, involves the attainment of the polarity transition corresponding to the termination of the Olduvai normal polarity event from lavas on Moloka, Hawaii. The derived record, when complete, will be rigorously compared to a published record of the same transition obtained from nearby deep-sea sediments. The second project involves the attainment of detailed paleofield behavior of sequential reversals recorded in exposed, rapidly-deposited marine sediments along the Mangapoike River on New Zealand's North Island. The sequence has been well-correlated to the late Miocene. Akaroa Volcano, on New Zealand's South Island - the previous focus of transitional field studies by this P.I. - appears to have been created contemporaneously with the marine sediments. This situation provides a rare opportunity to compare transition records derived from two paleomagnetically distinct, yet desirable rock types. As has been the case with past paleomagnetic projects at Cal Poly, several undergraduates will take part throughout the proposed projects, from assistance in the field to laboratory analysis. Some will undertake an aspect of the original research as their own and produce a senior project.