太阳顶群预富集过程中的生物成矿作用  

BIOMINERALIZATION IN THE PRE ENRICHMENT OF TAIYANGDING GROUP

作　　者：林丽[1] 朱利东[1] 文锦明[2] 

机构地区：[1]成都理工学院地质学系 [2]四川地矿局川西北地质队

出　　处：《成都理工学院学报》1997年第1期64-72,共9页Journal of Chengdu University of Technology

基　　金：国家自然科学基金

摘　　要：隶属于西秦岭南亚带的拉尔玛金矿床赋存于寒武系太阳顶群中，太阳顶群主要有硅质岩和碳质板岩两类岩石。金与有机碳的关系、矿（岩）石的浸出率与有机碳含量的负相关、微量元素和稀土元素Ｑ型聚类分析及有机质、粘土矿物吸附和释放金的现代模拟实验表明：太阳顶群热水成因的硅质岩构成了拉尔玛金矿床主要的矿源层。太阳顶群硅质岩的有机地球化学研究表明，与金关系密切的有机质的生物先质体为海生低等菌藻类生物。硅质岩中金含量与菌藻生物化石量的正相关关系又进一步说明了拉尔玛金矿床矿源层形成过程中，这些海生菌藻生物起了重要的作用。现代菌藻生物成矿的实验研究表明：（１）菌藻生物对金有明显的富集作用，但不同的生物对金的富集作用强弱不同，蓝细菌较绿藻对金的富集作用强烈，热水环境生物较常温条件下的生物对金的富集作用强烈；（２）蓝细菌生物较粘土矿物、沉积物和生物降解的有机质对金的富集作用强；The Laerma gold deposit occurs in the Cambrian Taiyanding Group of the Southern Belt of West Qinling. The characteristics of ore geochemistry and regional geochemistry denote that the metallogenic material of the deposit originated from its matrix - the Taiyanding Group. There are two principal rock types in the Taiyanding Group, the siliceous rocks and the carbonaceous slates. The gold and the organic carbon are uncorrelated in the carbonaceous slates, no matter the latter is metallized or not. Instead, the gold and the organic carbon in the siliceous rocks show positive correlatability in unmetallized strata but negative correlatability in metallized strata. The retrieval rate of gold through soaking and retrieving experiments of the metallized and unmetallized rocks show negative correlation with the organic carbon contents, and the retrieval rates of the organic carbon rich slates are generally lower than those of the siliceous rocks. Q mode cluster analysis shows that the microelement composition of ores of both siliceous rock type and slate type demonstrates coincidence and inheritance with siliceous rocks. All these evidences indicate that mobility of gold is much higher in siliceous rocks than in slates, which makes gold in the former ready to remobilize to contribute in the metallogenesis; whereas gold in the slates is mainly inert and difficult to remobilize. Thus, the siliceous rocks are the source beds of the Laerma Gold Deposit. The gold adsorbing and releasing experiment of organic matter and clay minerals show that: (1)the gold adsorbing ability of organic matter is at least 6.89 times higher than that of pure clay minerals; (2)participation of clay minerals decreases the gold adsorbing ability of organic matter; (3)gold releasing ability of both organic and clay minerals decreases remarkably under 300℃. Experimental results also yield the following theoretical estimation: the retrieval of gold from the siliceous rocks of Taiyangding Group makes 99.20 percent of the total retrieval, while t

关 键 词：金矿床 生物成矿作用 富集过程 太阳顶群 

分 类 号：P618.810.5[天文地球—矿床学]