Observation of manganese nodules and encrustations in various lakes of Finland

The limnic ferromanganese ore concretions in some Finnish lakes are described. Their chemical and mineral compositions have been measured as have their natural surroundings —...本文对芬兰部分湖泊中的淡水铁锰矿石结核进行了描述。已测定其化学与矿物组成，以及天然赋存环境的相关参数——