陆缘南海成矿金属存在形式和沉析作用的定量研究

QUANTITATIVE RESEARCHES ON EXISTENCE FORM OF OREFORMING METALS AND SEDIMENTATION IN THE PERICONTINENTAL SOUTH CHINA SEA

通过溶液化学平衡反应模型理论计算表明：软泥水和底层海水除Ｆｅ在软泥水中呈高价态的分子化合物（Ｆｅ（ＯＨ）３）和络合离子（Ｆｅ（ＯＨ）２＋），以及二者均存在含量甚微的单一离子Ｆｅ３＋以外，Ｆｅ的其它组分形式和Ｍｎ、Ｃｕ、Ｎｉ、Ｃｏ元素均以低价态的单一离子、络合离子和分子化合物形式存在。软泥水比底层海水的组分存在形式要多，且组分含量变化幅度要大。软泥水中Ｆｅ主要含量是Ｆｅ（ＯＨ）３，而底层海水主要是Ｆｅ２＋。软泥水现代正在发生沉析的矿物有：赤铁矿、针铁矿和石英，在外陆架—陆坡海域软泥水可生成方解石、文石，陆坡海域的软泥水还可沉析菱锰矿和水锰矿；底层海水正在沉析的仅是方解石、文石、赤铁矿和针铁矿。碳酸盐类矿物的沉析与海底分布的钙质粘土、泥等沉积物相吻合。水锰矿的生成为陆坡海山区存在的多金属结壳（核）提供了成矿信息，并表明多金属结壳（核）不是通过海水的物理化学作用的途径生成的。

おheoretic calculation through fluid chemical balance reaction model shows that both ooze water and sea bottom water have Fe,Mn,Cu,Ni and Co exist in the forms of single ions,complexing ions and compounds at low valence except a very small number of ferric ions in the both water and ferric iron in (Fe(OH)3)and (Fe(OH)3)in the ooze water.The ooze water has more existing compounds than the sea bottom water.Fluctuation of the content is large.Main content of Fe is Fe(OH)3 in the ooze water,and Fe2+ in the sea bottom water.In the ooze water,the present sedimentary minerals are hematite,goethite and quartz but calcite and aragonite on outer shelfslope area and rhodochrosite and manganite on the slope.In the sea bottom water the present settlement is calcite,aragonite,hematite and goethite.Carbonate mineral settlement is coincident with distributions of calcareous clay and mud at the sea bottom.The occurrence of manganite at the slope indicates the formation of polymetallic nodules(crusts) and demonstrates that the polymetallic nodules(crusts) are not results of physical and chemical actions of sea water.