Annotated record of the detailed examination of Mn deposits from the 7TOW cruise among the Line Islands Guyots in the Pacific Ocean

Volcanic rocks dredged from the tops of seamounts in the Line Islands and cored from their flanks demonstrate that this is a region of extreme petrologic diversity. Tholeiitic and alkalic basalts were obtained in a single dredge haul and a wide spectrum of alkalic differentiates, including quartz trachytes, and phonolites were dredged or cored elsewhere. Four dredge stations on widely scattered seamounts recovered potassic nephelinites, unlike any other volcanic rocks heretofore found in the ocean basins. These rocks include amphibole and biotite-bearing varieties, some of which are leucite normative.

从莱恩群岛（Line Islands）海山（seamount）顶部拖网采集、并从其侧翼取岩芯获取的火山岩样本表明，该区域具备极强的岩石学多样性。单次拖网采样作业即可同时获得拉斑玄武岩（tholeiitic basalt）与碱性玄武岩（alkalic basalt）；在其他站位还通过拖网或岩芯取样，获取了涵盖石英粗面岩（quartz trachyte）、响岩（phonolite）在内的广谱碱性分异产物。分布于四处分散海山的四个拖采样点，采获了钾质霞石岩（potassic nephelinite），这类岩石与迄今在洋盆中发现的所有其他火山岩均截然不同。该类岩石包含含角闪石（amphibole）与黑云母（biotite）的岩相，其中部分属于白榴石标准矿物（leucite normative）组合。