西太平洋海底平顶山研究

INVESTIGATION OF GUYOTS IN THE WESTERN PACIFIC OCEAN

太平洋西部海底有很多平顶海山 ,在这些平顶海山的斜坡上 ,分布着富钴结壳。以近年来“海洋四号”船在西太平洋调查的资料为依据 ,通过对平顶山的地形地貌、表层沉积物和沉积地层以及岩石特征的分析研究 ,认为这些海底平顶山原来是一些出露于海平面的火山岛屿 ,在海浪的冲击和海流、海水的冲刷、侵蚀作用下 ,逐渐削蚀成略低于海面的平台 ,以后平台逐渐下沉 ,经过漫长的地质岁月 ,终于成为隐藏于海面以下 10 0 0～ 2 0 0 0

There are many guyots(flat topped seamounts)on seafloor in the west of Pacific Ocean.There are crusts rich in cobalt on the slope of these guyots.Data used in the paper were obtained by “R/V Haiyang IV” survey in the western Pacific Ocean in recent years.Through a comprehensive analysis and investigations of the characters about topography and landforms,seafloor surface sediments,strata and rock,we consider that these guyots are originally some volcano islands above sea level.Under actions of sea wave and erosion of sea current and seawater,they gradually turn into platforms lower than sea level.Then the platforms subside gradually over a very long geological time,and finally become guyots 1000～2000 m below sea level.