中太平洋海山群漂移史及其来源

中太平洋海山群的海山呈簇状排列且近EW向展布于太平洋海山密集区，其四周分布着一系列NW走向的线性列岛及规模巨大的水下海山链。它位于明显属于海山链构造的夏威夷群岛和马绍尔群岛之间，处于莱恩群岛的北西向延伸方向上，与热点作用的板内火山作用关系密切。结合前人对中太平洋海山群形成和漂移的认识，从板块运动和几何学角度出发，采用Backtracking和Hot-spotting海山追踪方法对该区海山进行了追踪，发现该区海山的热点源主要位于现今法属玻利尼西亚群岛区（法属玻利尼西亚热点群），这与前人从古地磁和钻探资料出发得到的结果相接近。研究表明，中太平洋海山群是多热点成因的板内火山作用和板块构造运动的共同产物，它在130～90Ma期间起源于法属玻利尼西亚热点群，曾随着太平洋板块发生过向南和向北的运动，既有水平方向的漂移又有垂直方向上的升降，在漂移和升降过程中还受到了当时大规模多期的热点活动和断裂活动的改造作用，经过一个漫长的过程后才到达今天的位置，最后形成了现今呈簇状分布的海山群。

RESEARCH ON DRIFTING HISTORY AND TECTONIC ORIGIN OF THE MID-PACIFIC MOUNTAINS

The Mid-Pacific Mountains are characterized by a great abundance of seamounts which cluster on the Pacific seafloor. Here is the center of distribution of seamounts in the Pacific. As a whole they trend EW. Around,there are a series of linear islands and large underwater seamount chains,which all trend NW. The seamounts lie in a region between Marshall Seamounts and Hawaiian Ridge. The formation is closely related to intraplate volcanism produced by hotspots. The authors majorly use the Backtracking and Hot-spotting methods to trace the Mid-Pacific Mountains from the movement of the plate and geometry based on the previous studies about this region. The result shows that the origin is situated in French Polynesian Islands(French Polynesian hotspots), which is consistent with the information from palaeomagnetism and DSDP/ODP. The Mid-Pacific Mountains belong to the collective products of intraplate volcanism that originates from multi hot spots and plate tectonics. The Mid-Pacific Mountains originated from the present French Polynesian hot spots, and then they drifted to present location following the spreading of the Pacific. At the same time they fluctuated and formed the islands that came out of the sea level. During their drifting and fluctuating, they were also affected by the activity of active fracture zones. And finally the present Mid-Pacific Mountains were formed.