(Table 1, Page 94) Elemental abundances in ferromanganese nodules and crusts from the Pernambuco Plateau and guyots off northeast Brazil

Ferromanganese deposits, mostly manganese crusts, are common in elevations along the northeastern Brazilian continental margin. Association of the deposits with more or less altered basaltic rock can be observed. On the Pernambuco Plateau and Ceara Guyot, ferromanganese deposits occur associated with phosphatic material and nodules. The mineralogical composition of the ferromanganese deposits indicates a predominance of the manganese oxide phase dMnO2. Low contents of Mn and Cu are characteristic of their chemical composition. Fe and Mn in the deposits probably precipitated from the sea water.铁锰沉积物（Ferromanganese deposits）以锰结壳（manganese crusts）为主要类型，在巴西大陆东北部边缘的海底隆起地带较为常见。可观测到该类沉积物与不同程度蚀变的玄武岩相伴产出。在佩南布科高原（Pernambuco Plateau）与塞阿拉海山（Ceara Guyot）区域，铁锰沉积物与磷质物质及结核伴生。铁锰沉积物的矿物组成表明其优势矿物相为二氧化锰相dMnO₂。其化学成分以低锰、低铜含量为典型特征。沉积物中的铁和锰大概率由海水沉淀形成。