Pacific Plate Motion 30-70 Ma: Seamount Geochronology in the Western Pacific and the Origin of the Hawaii-Emperor Bend

海洋热点留下的火山痕迹可以用构造板块运动来解释。太平洋板块的运动最显著地反映在夏威夷/皇帝海山链上，其特征是在42 Ma左右弯曲。根据岩石的年代测定，这种变化的时间比根据海洋磁异常计算出的年龄要年轻近1000万年。有人提出，夏威夷的热点可能相对于其他热点发生了移动。吉尔伯特脊和托克劳海山链在其南端末端显示出类似的弯曲，这为提高我们对太平洋板块绝对运动的准确性和测试固定热点概念的有效性提供了机会。该项目将从这些海山链中挖掘岩石，并通过40 Ar/39 Ar同位素方法确定样品的年代。

SUMMARYOceanic hot spots leave trails of volcanoes that can be interpreted in terms of tectonic plate motion. The motion of the Pacific Plate is most prominently reflected in the Hawaiian/Emperor seamount chain with a characteristic bend at about 42 Ma. The timing of this change based on dating of rocks is almost 10 million years younger than the age calculated from marine magnetic anomalies, and it has been suggested that the Hawaiian hot spot may have moved with respect to other hot spots. The Gilbert Ridge and the Tokelau seamount chain display a similar bend at their southern terminations, and offer an opportunity to improve our accuracy of absolute Pacific Plate motion and to test for the validity of the fixed hot spot concept. This project will dredge rocks from these seamount chains and date samples by 40 Ar/39 Ar isotopic methods.