(Table 1, page 24), Geochemical cmposition of nodules and crust from the Indain Ocean recovered from R/V Marion Dufresne expeditions

Mineralogical analysis of manganese nodules and crusts collected from Indian ocean aboard Marion Dufresne points to a depth and regional control upon the manganese oxide association: vernadite - birnessite and vernadite - todorokite. Moreover, progressive changes in the vernadite/birnessite ratio as a function of time is clearly seen. Magnetite and titano-magnetite in quantities similar to those of framboidal pyrite in manganese nodules are outlined for the first time. Study of the distribution of metals (Mn, Fe, Ni, Cu, Co) shows a strong latitudinal and regional dependence that may be connected to high productivity zones and to bottom water properties. The problem of mineralogical control on the chemical composition is approached. Finally, it results that any interpretations taking into account all these data haveway to give to the variability of sea-water properties (pH, oxygenation, motions) the prominent control upon manganese nodules composition.

搭乘马里恩·迪弗雷斯纳号（Marion Dufresne）科考船从印度洋采集的锰结核（manganese nodules）与铁锰结壳（crusts）的矿物学分析结果表明，其锰氧化物组合受水深与区域环境的共同制约，该组合包括水锰矿（vernadite）-水钠锰矿（birnessite）以及水锰矿-钡镁锰矿（todorokite）。此外，可清晰观测到水锰矿/水钠锰矿比值随时间呈现的渐进式变化。本研究首次在锰结核中发现了含量与草莓状黄铁矿（framboidal pyrite）相当的磁铁矿与钛磁铁矿。对金属元素（Mn、Fe、Ni、Cu、Co）分布特征的研究显示，其分布具有显著的纬度与区域依赖性，这可能与高生产力海域及底层水团性质相关。本研究还探讨了矿物组合对化学成分的制约机制这一科学问题。最终研究表明，若要基于所有上述数据开展合理阐释，必须将海水性质（pH值、氧化状态、水动力运动）的变化作为锰结核成分变化的主导制约因素。