摘要
白果园银(钒)矿床产于震旦系陡山沱组黑色岩系中。矿床的地球化学和有机地球化学研究表明,黑色页岩含丰富以低等海生生物为主的腐泥型有机质,黑色页岩形成于局限的滞留海盆。陡山沱期海平面上升导致海盆发育O-A-E三层结构的水柱,在E层水富H_2S的还原环境下,死亡生物有机体被还原细菌快速分解,而银、钒在富还原硫环境中活动性降低,滞留在沉积物中而发生初始富集。
Baiguoyuan Silver-Vanadium deposit is hosted by the Upper Sinian Doushantuo Formation black shales that were rich in Ag (up to 250ppm) and V (V2O5 up to 2. 484 weight percent). Studies on geochemistry and organic geochemistry show that the black shales contain amount sapropelic organic matter deriving from marine plankton and their DOP (degree of pyritization) values is very high, greater than 0. 70, indicating a euxinic bottom water environment. The marine transgression during the early Early Sinian was responsible for the formation of the black shales rich in Ag and V and organic carbon. The sea level rise during transgression made the water cloumn thicker and a oxic-anoxic-euxinic three-storeyed structure of water cloumn formed. Marine organisms collecting Ag and V from sea water and were deposited on the surface of sediment covering by euxinic bottom water. Within such a euxinic condition, organic matter would be decomposed rapidly by reducing bacteria; however, Ag and V appeared inactive in a reduced euxinic environment rich in H2S and they might be obserbed by residual organic matter, clays or Fe, Mn oxide/hydroxide, or surface-complexed with pryite formed in the early diagenesis. After a long sedimentation peroid, the balck shales that were rich in both Ag, V and organic matter formed.
出处
《地质论评》
CAS
CSCD
北大核心
1997年第4期373-380,共8页
Geological Review
关键词
黑色岩系
银矿床
钒矿床
沉积环境
古环境
Baiguoyuan Ag(-V) deposit, black shale , organic matter, preliminary enrichment
