邓阜仙花岗岩的构造环境、岩浆来源与演化

本文利用An-Ab-Or-Q-H_2O体系相图等对邓阜仙复式岩体的分析研究表明。四期花岗岩为同一深部岩浆房岩浆结晶分异演化的产物,岩浆房深度约为12km,并且该岩体的主体第一期岩浆也经历了部分就地结晶分异作用。邓阜仙岩体不仅仅具有S型花岗岩特征,而且还显示出某些Ⅰ型花岗岩的特征,其源岩可能为前寒武纪的正、副变质岩混杂的岩石。该岩体总体上形成于同碰撞构造环境,且从第一期到第四期有着同碰撞向板内花岗岩变化的趋势,反映了本区从印支到燕山晚期陆壳成熟度不断增强的过程。

TECTONIC SETTING, MAGMATIC SOURCE AND EVOLUTION OF DENGFUXIAN GRANITE

In this paper, phase diagrams of An-Ab-Or-Q-H2O system are used to analyse Deng- fuxian composite massif. The results show that all the four stage granites are products of crystallization differentiation from the same magma reservoir; the depth of the magma reservoir is about 12 km; the first stage granite had also undergone crystallization differen- tiation on the spot. Not only does Dengfuxian granite have the features of S-type granite, but it also displays some characteristics of I-type granite. Its source rocks may be mixed rocks from orthometamorphite and parametamorphite of Precambrian. The Dengfuxian granite overally formed at syn-collision tectonic setting,and from the first to the final stage showed a tendency from syn-collision granite to intra-plate granite, which reflects that the maturity of the crust in this region was increasing from Indo-Chinese epoch to late Yan- s han epoch.