(Table 1, page 643) Spectrochemical analyses of samples from dredge haul AMPHITRITE D2. Three different fragments of red ferruginous rock

Along with specimens of manganese oxides and basalt, rocks containing more than 30 percent iron by weight and consisting mainly of poorly crystallized goethite have been dredged from the flanks of a seamount located on the East Pacific Rise. The Fe-Mn ratio varies widely among the various oxide rocks deposited at this locality and at another seamount in the same area. The deposit was probably formed by fractional precipitation of iron and manganese which had been introduced locally into the bottom water by hydrothermal solutions of volcanic origin, and by leaching from deep-sea basaltic lavas.

本研究从位于东太平洋海隆（East Pacific Rise）的一座海山侧翼拖网采集到含铁量（重量占比）超30%、主要成分为弱结晶针铁矿（goethite）的岩石，同时还获取了氧化锰矿物标本与玄武岩标本。在该采样点及同区域另一座海山所沉积的各类氧化物岩石中，铁锰比（Fe-Mn ratio）差异显著。该矿床的形成大概率由两大过程共同促成：火山成因的热液溶液将铁、锰物质局部注入底层水体，加之深海玄武岩熔岩的淋滤作用，最终使铁锰发生分级沉淀而成矿。