(Table 1, page 146) Iron, manganese and nickel contents of 21 ferromanganese nodules from Combe D'Izame and Mont Peyroux, Montagne Noire

Ferromanganese nodules (equivalent to Recent manganese nodules) are described from the Upper Devonian griotte (red pelagic limestone) of the Montagne Noire (S. France) and the Cephalopodenkalk of the Rheinisches Schiefergebirge, West Germany. They occur as encrustations, commonly exhibiting colloform structures, around skeletal material and limestone clasts. The nodules are associated with encrusting foraminifera and a development in the sublittoral environment is envisaged. Chemically, the ferromanganese nodules are depleted in manganese relative to iron, compared with Recent nodules, a loss which is attributed to diagenetic migration of manganese. Electron probe studies show that manganese covaries positively with calcium, but negatively with iron and silicon. Diagenetic enrichment of hematite occurs in the griotte at hardground horizons where two periods of mineralization can be established. The Devonian ferromanganese nodules show that solution of nodules has not occurred on burial.铁锰结核（Ferromanganese nodules）可类比现代锰结核，本次研究的样品采自法国南部蒙塔涅诺尔（Montagne Noire）地区的晚泥盆世格里约特灰岩（griotte，即红色远洋灰岩），以及西德莱茵兰页岩山脉（Rheinisches Schiefergebirge）的头足类灰岩（Cephalopodenkalk）。该类结核以结壳形式产出，常附着于骨骼物质与灰岩砾石表面，普遍具有胶状构造（colloform structures）。此类结核与附生有孔虫伴生，研究推测其形成于浅海亚潮带环境。化学特征方面，相较于现代锰结核，本次研究的铁锰结核中铁元素相对锰元素更为富集，这种锰元素的亏损被归因于成岩作用过程中的锰迁移。电子探针分析结果显示，锰元素与钙元素呈正相关关系，而与铁、硅元素呈负相关关系。在格里约特灰岩的硬底（hardground）层位中，发生了赤铁矿的成岩富集作用，据此可确定两期成矿事件。本次研究的泥盆纪铁锰结核表明，结核在埋藏过程中并未发生溶解作用。