华南板块北缘东段武功山加里东期花岗岩特征及成因探讨

Features and genesis of Caledonian granites in the Wugongshan in the eastern segment of the northern margin of South China plate

摘要: 提要：华南板块北缘东段武功山地区出露大面积的片麻状花岗岩，前人在该区工作时认为属混合成因的“混合岩”，本次工作证实属同熔性花岗岩。采用岩石谱系单位法进行研究，共划分出5个单元，归并为2个超单元。其成岩年龄（U-Pb法）分别为（462.3±3.2）Ma、（409.4±5.1）Ma，属加里东期造山花岗岩。后又经印支—燕山期伸展滑覆构造的叠加、改造，形成片麻状花岗岩。

Abstract: Abstract：Gneissic granites are exposed over large tracts in the Wugongshan (Wugong Mountains) in the eastern “segment on the northern margin of South China. Previous studies suggested that these rocks belong to migmatites” of migmatitic origin. This study has verified that these rocks belong to syntectonic granites. On the basis of a study of the hierarchical units of the rocks, five units have been distinguished, which may be grouped into two super-units. The rocks have U-Pb ages of 462.3±3.2 Ma and 409.4±5.1 Ma respectively, belonging to Caledonian orogenic granites. After their formation they underwent overprinting and reworking of Indosinian-Yanshanian extensional-sliding superimposed structure.