甘肃寒山金矿区黄钾铁矾的形成机制及其地质意义

在分析寒山金矿区原生矿物和氧化矿物组合的基础上，通过对黄钾铁钒的热力学计算分析得出：在常温条件下，黄铁矿要形成黄钾铁钒，所需的氧逸度较低，但需要有一个较高的碱性、富钾、富Fe2＋以及富水的环境，这一条件暗示了围岩为富铁的基性火山岩在湿润的气候条件下有利于形成黄钾铁钒，同时也表明寒山金矿区氧化带的形成过程中，其气侯环境不是现在的沙漠干旱气候，而是湿润动植物繁盛的大陆性气候。结合区域地质特征，可以得出寒山金矿的氧化带可能形成于早侏罗世-中侏罗世。

GENESIS OF JAROSITE IN THE HANSHAN GOLD MINE OF GANSU PROVINCE AND ITS GEOLOGICAL SIGNIFICANCE

Based on the primary. and secondary mineral associations in the Hanshan gold deposit, the thermo-dynamic analysis of jarosite shows that at normal temperature, pyrite can be oxidized into jarosite un-der low oxygen fugacity in such an environment as being high in alkali, rich in K and Fe and sufficientin water. This suggests that the Fe-rich basic rocks as ore-hosted rocks be favorable to the formation ofjarosite under humid climate. During the process of formation of the oxidized zone in the Hanshan goIdmine, the climate was not a desert dry climate as what it is now, but a humid continental climate un-der which animals and plants were flourishing. In combination with the regional geological characteris-tics, it can be inferred that the oxidized zone of the Hanshan gold deposit might have been formed inthe Early to Middle Jurassic.