甘肃省沃尔给花岗岩体中黑云母的成分对其岩体碱度的响应及成岩成矿意义

发布时间：2019-05-08 02:34

【摘要】：矿床的形成与其成矿地质体的成因和岩石化学性质密切相关,因此有必要对岩体碱度与成矿关系进行深入研究。通过甘肃省沃尔给花岗岩体的采样测试,并对国内52个各类矿床中与成矿有关岩体中黑云母的主量元素化学成分进行统计和分析,进行寄主岩石碱度判别。研究结果显示:研究区与Cu、Au成矿有关的岩体位于高碱度区域内,而与Sn矿形成有关的岩体均属于低碱度岩石系列。岩浆熔体早期至岩浆后期热液阶段,氧逸度的变化由高到低,介质的碱度逐渐增强,Cu、Au矿床的形成大致经历上述的成岩成矿过程。岩浆结晶过程早期低氧逸度、高碱度有利于Sn的活化迁移,岩浆期后热液阶段的高氧逸度、低碱度有利于锡石的沉淀,但是由于锡石沉淀过程中不断消耗O_2,致使其较高的氧逸度显著降低。认为碱度与氧逸度之间相互作用、相互影响进而引起矿化的发生。
[Abstract]:The formation of the deposit is closely related to the genesis and petrochemical properties of the ore-forming geological body, so it is necessary to study the relationship between the alkalinity of rock mass and mineralization. The main elements of biotite in 52 ore deposits in China were analyzed by sampling and testing of granitic bodies in Wolle, Gansu Province, and the alkalinity of host rocks was distinguished. The main elements of biotite in ore-forming related rocks in China were statistically analyzed and analyzed in order to distinguish the alkalinity of host rocks. The results show that the rock bodies related to Cu,Au mineralization in the study area are located in the region with high alkalinity, and those related to the formation of Sn ore belong to low alkalinity rock series. From the early stage of the magma melt to the hydrothermal stage of the late magmatic stage, the oxygen fugacity changes from high to low, and the alkalinity of the medium increases gradually. The formation of the Cu,Au deposit generally goes through the diagenetic ore-forming process mentioned above. In the early stage of magmatic crystallization, low oxygen fugacity and high basicity are beneficial to the activation and migration of Sn. High oxygen fugacity in post-magmatic hydrothermal phase and low basicity are beneficial to cassiterite precipitation. The higher oxygen fugacity decreased significantly. It is believed that the interaction between alkalinity and oxygen fugacity leads to mineralization.
【作者单位】：中国地质大学(北京)地球科学与资源学院;甘肃鼎丰矿业有限责任公司;加拿大拉瓦尔大学地质与地质工程系;
【基金】：国家自然科学基金项目(41072070)
【分类号】：P588.121;P611

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