(Table 2, page 110) Chemical analyses of Mn crust samples from the Lametino Seamount in the Tyrrhenian Sea

Specimens dredged from within the summit of a volcanic seamount during an oceanographic cruise in the Eolian Island Arc (South Tyrrhenian Sea) where examined. Mineralization, which forms veins and pockets within a silty-clayey material, consists mainly of todorokite with scarce birnessite. The chemistry (Mn 48%, Fe 0.26 %, Ni 249 ppm, Co 223 ppm) and the mineralogy of the deposit are discussed; the findings, compared with data from some of the literature, suggest a hydrothermal genesis with extreme fractionations of Mn from Fe. A process explaining the anomalous Cu content (8 200 ppm) of the deposit is also suggested.

本研究对在伊奥利亚岛弧（南第勒尼安海）开展的某次海洋科考巡航中，从某座火山海山山顶区域拖网获取的标本进行了检验分析。赋存于粉砂质黏土物质中的脉状及囊状矿化体，主要由钙锰矿（todorokite）与少量水钠锰矿（birnessite）组成。本文对该矿床的化学成分（锰含量48%、铁含量0.26%、镍249ppm、钴223ppm）及矿物学特征展开了讨论；结合部分文献数据对比分析后，研究结果表明该矿床属于热液成因，且锰与铁发生了极强的分异作用。此外，本文还提出了一种可解释该矿床异常高铜含量（8200ppm）的成因机制。