西藏崩纳藏布砂金矿中金的来源研究

藏北高原砂金广布,岩金找矿却一直没有突破。对藏北规模最大的崩纳藏布砂金矿区地质环境、砂金产出层位及其成分特征、砂金的粒度与形态、砂金成分、相关重矿物组合等的详细研究发现,砂金富集的层位及程度与相应层位中隐晶质硅质结核或全硅质胶结物存在与否及含量高低具有密切关系。研究表明,本区砂金矿床的金源于地球深部,是由地热泉带出地表,并迅速转入地表表生作用,由于水化学环境等条件的改变而发生迁移富集的。体现了一种内外生连续成矿作用的成矿机制,对于深入认识高原地区具体地质条件下砂金矿床的成矿以及砂金作为岩金找矿标志意义等问题具有重要意义。

Research on the source of Au in Bengnazangbu placer gold deposit, Tibet

Placer gold deposits are wide spreading in the northern Tibetan plateau, hut rock gold exploration has no penetration yet. Through detailed research on geological environment, placer gold occurrence horizon, placer gold granularity, shape, composition, and correlative heavy mineral assemblage of Bengnazangbu placer gold deposit that is the largest in northern Tibet, we discover that the placer gold enriched horizon and degree are mutually correlated with the content of cryptocrystalline siliceous concretion or siliceous cement. The research shows that in this gold deposit, gold is from deep Earth, and it was carried out by terrestrial hot spring and then turned into surface supergenesis, and gold was transferred and enriched owning to change of water - chemical environment. This embodies a continuous mineralizational mechanism of endogenous and exogeneous mineralization, which has important significance for recognition of the placer gold mineralization and rock gold exploration sign.