新疆诺尔特地区阿提什花岗岩体岩浆演化动力学

Dynamics of Magma Evolvement of Atishi Granite Body in Nurt Area,Xinjiang

新疆诺尔特地区花岗岩分布广泛，其中阿提什花岗岩体与燕山期阿克提什坎金矿床在时问、空闻上密切相关，该岩体为二长花岗岩，具铝过饱和特征，属于高钾钙碱性系列。为探讨阿提什花岗岩体与阿克提什坎金矿床成矿的关系，从动力学角度探讨了燕山期阿提什花岗岩体的岩浆演化机理。瑞利数计算结果远远大于10^4，显示阿提什花岗岩体岩浆中对流作用是存在的。模拟计算显示，分凝作用是存在的，分凝作用对于大颗粒的残余体的分离作用明显，而对于小颗粒的残余体的分离作用很小。晶体分布参数S介于10^-7～10^-3间，显示岩浆中晶体基本上是自由浮动的，晶体的运动受流体的运动控制。斜长石粒度分布的体视学特征显示，在对流条件下，岩浆成分通过晶体与熔体的差异运动而发生变异。

The Nurt area is located in the north of Altay, Xinjiang,where the granites are widely exposed. The intrusion is adamellite and belongs to high kalium cal-alkaline series with peraluminous characteristics, showing an osculating relationship with the Aketisikan gold deposit. The paper studies the evolvement of magma of Atishi intrusion formed at Yanshanian stage through dymamics of magma and calculated the dynamics parameters,including viscosity,density and Raileigh. The Raileigh value is higher than 10^4 , indicating the existence of convection of magma. The simulation shows that the segregation separation of the big relicts is obvious, and that of the small relicts is little. The crystals distribution parameter S values range from 10^-3 to 10^-7,indicating that the crystals were floating in magma and controlled by the movement of liquid. The stereology characteristics of plagioclase indicate that the component of magma changed through differential movement between crystal and melted with convective condition.