大洋多金属结核的成矿作用和模式

以成矿作用反应场中的成矿物质和成矿环境为切入点,指出洋底水-沉积物界面附近形成了金属垒、碱性垒和氧化垒的垒群带以及矿物的沉析带;溶解态成矿金属的存在形式除Fe主要呈高价态外,Mn、Cu、Ni、Co均呈低价态;洋底沉析的矿物有赤铁矿、针铁矿、石英、硅酸盐类和碳酸盐类矿物。成矿溶液中存在富含Mn、Fe的胶体和微粒,其Mn、Fe含量比溶解态的高出百倍至千倍,Cu、Ni、Co含量也以增高为主。南极底层流的供氧使表层沉积物均呈浅黄、黄褐、褐色系列色调,并且成矿溶液呈低温、弱碱性、强氧化环境。在构筑成矿金属运聚和分异的动态模型基础上,提出了氧化、胶体化学和生物化学是结核生成的作用链,归纳为以洋底垒群带和矿物沉析带的复合带为背景、胶体化学作用为主导、物理化学作用和生物化学作用叠加的外生成因水下沉析的结核成矿模式。

MINEROGENESIS AND MODE OF POLYMETALLIC NODULES IN THE OCEAN

In the metallogenetic convergence field,the metallogenesis and growth environment is considered as a core to be described and calculated in various aspects.The results indicate that at the bottom of the ocean close to the interface of the sediments are formed the metalliferous barrier,the alkaline barrier and the oxidized ore barrier as a barrier group and mineral settling-out zone.Metallogenetic elements in the solution state such as Mn,Cu,Ni and Co all present low valence with the exception of Fe in high valence.The settlingout minerals are hematite,goethite,quartz,silicate and carbonate at the bottom of the ocean.The metallogenetic solution is rich in colloid and particles of Mn and Fe which are about 100 to 1000 times higher than that of the solution. The content of Cu,Ni and Co increases in majority.The top sediments at the bottom present light yellow,yellowish brown and brown series,and the metallogenetic solution is in low temperature,weak alkaline and strong oxide environment due to the oxygen-supplying bottom Antarctic current.The dynamic modeling of the metallogenic accumulation and separate conditions indicate that the oxidation,colloid chemical and biological reactions are the chains to produce nodules. The conclusion is that the metallogenetic mode is the exogenetic suboceanic separation affected by colloid chemical majority with physical-chemical and biological reactions in the compound zone of the suboceanic barrier group and separate conditions.