阿尔泰诺尔特地区花岗岩岩浆的分凝作用

Segregation of granitoid magma in the Nurt area,Altay

诺尔特地区位于阿尔泰北部山区 ,西伯利亚板块西南缘。花岗岩广泛分布 ,主要为加里东晚期、华力西中晚期及燕山期花岗岩。文章选取诺尔特地区各时期代表性岩体进行岩浆分凝作用的研究 ,确定的动力学参数包括岩浆的含水量、粘度及密度。分凝速度的计算表明 ,区内各岩体花岗质岩浆中分凝作用是存在的 ,但是分凝速度较小 ,分凝作用对于大颗粒的残余体的分离作用是明显的 ,而对于小颗粒的残余体的分离作用很小。经过分凝作用之后 ,岩浆的成分发生了变化 。

The Nurt area is located in the north of Altay,at the southwest of the Siberia plate.The granites which formed at late Caledonian stage,middle Hercynian stage,late Hercynian stage and Yanshanian stage are widely exposed in the Nurt area.This paper investigates the segregation of the representational granite at each stage and some dynamics parameter of magma are calculated, including the water content,the viscosity and the density of the magma.The results of the segregative velocity show that the segregation exist in the magma. The segregative velocities are lower.The big crystals were affected by the segregation obviously and the small crystals were hardly affected by the segregation.The segregation caused the component variation of the magma and the small crystals still existed in the magma.