深海海底铁锰结核的成因研究与人类认识海洋的进步如影相随。根据铁锰结核物质来源的不同，全球海底的铁锰结核 主要分为上覆海水来源的水成型、沉积物间隙水来源的成岩型和这两个来源都有的混合型等三种主要成因类型。水成型结 核的表面比较光滑，结核的Mn/Fe比值<2，Co含量与∑REE(稀土元素总量)较高，生长速率较低；而成岩型结核一般有比 较粗糙的外表，结核的Mn/Fe比值>2，Cu与Ni含量较高，生长速率相对较高。由于锰结核中的锰矿物结晶程度普遍很差， 有关锰矿物的鉴定十分困难，不同研究人员之间有关锰矿物的定名经常有不同程度的混淆。目前，一般认为，水成型结核 中的锰矿物主要是水羟锰矿(δ-MnO2)，而成岩型结核中主要为10Å-锰酸盐(10Å-manganates)。全球海底铁锰结核的分 布、结核成因类型及其大小、丰度，以及结核的矿物-化学成分等的变化实际上反映了海洋初级生产力、碳酸盐补偿深度与 最低含氧带等海洋学特征在不同海域中或者不同地质历史时期上的变化。经过100多年大量的研究，人们对铁锰结核成因的 认识已经取得了长足的进步，然而，一些根本性的谜团还没有解开。

 Deep sea manganese nodules are classi?ed into three genetic types: hydrogenetic, diagenetic and mixed, according to their major metal sources. Hydrogenetic manganese nodule, derived from precipitates from sea water column, is generally characterized of smooth surface, Mn/Fe ratio <2, higher concentration of Co and ∑REE, and slower growth rate. In contrast, diagenetic manganese nodule, from pore water in sea?oor sediemnts, is of rough surface, Mn/Fe ratio >2, higher concentration of Cu and Ni, and relative faster growth rate. Classi?cation and identi?cation of ferromanganese minerals of manganese nodules have been very dif?cult and confused as most of or nearly all of them are amorphous and/or poor crystallized. Up to date, it is commonly accepted that major manganese minerals in hydrogenetic and diagenetic nodules are d-MnO2 and 10Å-manganates, respectively. Globally variation of nodule distribution, nodule types, nodule abundance, mineral and chemical composition in nodules is mainly controlled by primary production, carbonate compensate depth and oxygen minimum zone. Although progresses have been largely achieved for the genesis studies of manganese nodules in deep sea by numerous great efforts in last ~100 years, metallogenetic mysteries are still remain to be further explored.