Chemical composition of manganese nodules from cruise KH-84-1 (R/V Hakuho-Maru)@en

Preliminary results of chemical analysis of thirteen ferro-manganese nodules dredged from the Mariana and Ogasawara regions via the KH-84-1 cruise are presented. Five Mn nodule samples from the stations of 16, 19, 23 and 25 in and around the Mariana Trough and seven Mn nodules at stations 2, 3, 5, 8 and 27 in the Ogasawara Plateau were selected for chemical analyses. Ferromanganese oxide crusts were separated from Mn nodules and were soaked into the distilled water for two days. After drying at 110°C for 12 hours, they were powdered in an agate mortar. About 500 mgr of each sample was dissolved in the mixture of dilute nitric acid and dilute hydrogen peroxide. After removing silicate residue by filtering, the solution was proceeded for induced coupled plasma (ICP) analysis at Tsukuba University. Abundances of rare earth elements (REE) and several trace elements were also determined by instrumental neutron activation analysis (INAA).本研究报道了通过KH-84-1航次从马里亚纳（Mariana）和小笠原（Ogasawara）海域拖采获得的13个铁锰结核的化学分析初步结果。本次分析选取了马里亚纳海槽（Mariana Trough）及其周边海域16、19、23、25号站位的5个锰结核样品，以及小笠原海台（Ogasawara Plateau）2、3、5、8、27号站位的7个锰结核样品。首先从锰结核中分离出铁锰氧化物结壳，将其置于蒸馏水浸泡两日；随后在110℃下烘干12小时，使用玛瑙研钵将样品研磨成粉。称取每份样品约500mg，置于稀硝酸与稀过氧化氢的混合溶液中溶解。经过滤去除硅酸盐残渣后，将溶液送至筑波大学（Tsukuba University）开展电感耦合等离子体（Inductively Coupled Plasma, ICP）分析。此外，还通过仪器中子活化分析（Instrumental Neutron Activation Analysis, INAA）测定了稀土元素（Rare Earth Elements, REE）及多种微量元素的含量。