Paleomagnetic Study of the Geomagnetic Secular Variation in New Zealand -- Comparison with the North Hemisphere

在新西兰北岛的Maroa-Taupo地区、Okataina地区和Auckland/Ngatutura/Alexandra玄武岩田的73个地点采集了K-Ar或C-14年龄的火山岩。从Maroa-Taupo地区采集的以焊接为主的火成岩K-Ar年龄覆盖了近2 m，通过统计比较Brunhes和Matuyama两代古地磁的长期变化，将阐明过去地磁场的重要特征。Okataina地区流纹岩熔岩的C-14年龄为5 ~ 22 ka，这为建立南半球古长期变化曲线提供了良好的机会。从Ngatutura/Alexandra玄武岩田收集了8个K-Ar年龄在1.5 ~ 2.5 Ma之间的玄武岩熔岩，可以弥补Maroa-Taupo地区Matuyama早期的少量数据。

Volcanic rocks with K-Ar or C-14 ages were collected at 73 sites from Maroa-Taupo area, Okataina area, and Auckland/Ngatutura/Alexandra Basalt Fields in North Island, New Zealand. K-Ar ages of mainly welded ignimbrites collected from Maroa-Taupo area cover the last 2 My, and statistical comparison of paleomagnetic secular variation between Brunhes and Matuyama chrons will clarify important features of the past geomagnetic field. C-14 ages of rhyolite lavas collected from Okataina area are 5-22 ka, and this will give a good opportunity to set up a paleo-secular variation curve in Southern hemisphere. 8 basalt lavas of K-Ar ages between 1.5 and 2.5 Ma were collected from Ngatutura/Alexandra Basalt Fields, and these will compensate small number of data in early Matuyama chrons from Maroa-Taupo area.