中国东北寒区的风化壳与砂金矿床

Weathering Crust and Placer Gold in ColdRegion of Northeast China

大、小兴安岭北部寒区发育有3个砂金富集区.大量的找矿实践表明,区内砂金矿床与内生成矿作用没有必然的联系,砂金矿床与区域发育的风化壳有着密切的空间关系,风化壳中的低温地球化学作用对区域砂金矿床的形成具有一定的控制作用.在砂金的形成过程中寒冻气候条件至关重要,寒冷的气候条件有利于风化壳的保存,同时,冰冻条件下的水文地质条件及电化学作用也有利于金在其中的活化、迁移、富集和生长.

There are three placer gold enrichment zones in the north of Da Hinggan and Xiao Hinggan ranges. Geological Exploration show that there is no relation between the placer gold deposit and endogenetic minerialization, The placer gold have a close relation with crust of weathering in this area. Low temperature geochemistry in crust of weathering play important role on the formation of placer gold in this area. In the past period, the cold climatecondition is an important for the placer gold , the cold climatecondition have advantage for preserve of the crust of weathering, In the frost condition, the hydrology of cold regionand electrochemical have a advantage for the gold migration and enrichment. The sulphide plays an important role on gold oxidation and reduction.