摘要
沿皖南祁门-歙县-三阳坑断裂带分布有大小11个花岗闪长岩体,大都具有片麻状构造,其岩石学、岩石化学特征和微量元素、稀土元素含量一致,后二者与中元古界板溪群千枚岩的含量紧密相关,表明这些岩体是同源的壳源重熔产物。根据稀上模式计算,它们是千枚岩在深变质条件下75％熔融的形成物。
11 biotite granodiorite bodies are distributed along the Qimen-Shexian-Sanyangkeng fault zone with an E-W strike in southern Anhui Province. The vast majority of these rockbodies show gneissic structures. The major rock-forming minerals of these rockbodies are oligoclase, K-feldspar, quartz and biotite. These rockbodies are very similar in chemical composition and characterized by Al2O3- and H2O-enrichment, low oxidation coefficient f' and differentiation index DI, and K2O>Na2O. The rockbodies are also similar in the contents of trace elements and REE and show a positive correlation with phyllites of the Ningwu Formation of the Middle Proterozoic. The data on their petrology, petrochemistry, trace elements and rare-earth elements show that these intrusions are of the crust-source type and resulted from remelting of the upper crust. The REE patterns show that the rockbodies are products of 75% remelting of the Ningwu Formation under high-grade metamorphism conditions.
出处
《地球化学》
CAS
CSCD
北大核心
1991年第2期186-196,共11页
Geochimica
