四川大渡河黑金台子金矿成矿流体稀土元素地球化学

Characteristics of rare earth elements in fluids inclusions of the Heijintaizi gold deposit, Daduhe areas, Sichuan Province

黑金台子金矿位于青藏高原东缘,赋存于大渡河剪切带的次级剪切带中。本文在对矿床成矿流体包裹体测试的基础上,通过对石英流体包裹体中的稀土元素、单矿物石英中的稀土元素、含金石英脉全岩稀土元素、赋矿围岩的稀土元素特征的研究,并结合区域上康定杂岩的稀土元素特征,讨论了成矿流体来源,证实了黑金台子金矿成矿流体具有深部来源的特征。石英流体包裹体中的稀土元素含量变化于1846.4×10-12～16003.4×10-12之间,分配模式为平坦型,具有轻重稀土元素分馏作用特征,明显不同于矿区外围元古宙康定杂岩中不同类型岩石的稀土元素特征,而类似于矿区赋矿岩石的特征。

The Heijintaizi gold deposit is located on the western margin of the Yangtze craton and also on the eastern margin of Tibet. The gold deposit is hosted in Proterozoic plagiaplite and controlled by a NS_trending ductile_brittle shear zone. Gold mineralization occurs mainly as auriferous quartz veins. This paper presents REE analyses of fluid inclusions and quartz which hosts the fluid inclusions as well as auriferous quartz veins. The results show that the REE content of fluid inclusions ranges from 1?846.4×10^(-12) to 16?003.4×10^(-12), that of quartz ranges from 2.15×10^(-6) to 4.35×10^(-6), and that of auriferous quartz veins varies from 2.59×10^(-6) to 7.70×10^(-6). Combined with REE characteristics of host rocks and Kangding complex in the area, the authors hold that REE characteristics of fluid inclusions give some clues to the origin of the ore_forming fluids, which must have been derived from deep fluids. The REE of fluid inclusions in quartz were also derived from deep fluids. It is concluded that a careful study of REE in fluid inclusions may play an important role in probing into ore genesis and fluid evolution.