关键词: 变质变形期次, 运动学特征, 大地构造属性, 中生代, 长乐-南澳断裂带, 变质岩

Abstract:

Metamorphic and deformed granitic rocks in the Changle-Nan’ao fault zone, located in the coastal area of Fujian and Guangdong Province, was formed in the earlier Late Jurassic, later Late Jurassic and Early Cretaceous periods. It’s evidenced that three stages of ductile deformation and related dynamic metamorphism were developed within the fault zone during Mesozoic era, which are evidenced by metamorphism, deformation, crosscutting relation of the foliation and U-Pb isotopic dating of different intrusions. The first stage is characterized by deep structural level plastic deformation and low amphibolite facies metamorphism, which took place at the end of the Middle Jurassic (155-145 Ma). The second, occurred in the Late Jurassic (145-137 Ma), is characterized by the middle-deep structural level ductile shear deformation and high greenschist facies metamorphism. The third was demonstrated by mid-shallow brittle-ductile shear deformation and low greenschist facies metamorphism and formed in the middle period of the Early Cretaceous (about 120 Ma). These shear deformations were dextral-thrusting from NWW to SEE (displacement about 21 km), sinistral-thrusting from NNW to SSE (with the displacement of about 84 km), and normal-dextral strike slip(displacement ca. 2 km), respectively. The Changle-Nan’ao fault zone is a continental intraplate giant ductile shear zone during the Mesozoic era.

Key words: metamorphic-deformation episode, kinematic characteristics, geotectonic setting, Mesozoic era, Changle-Nan’ao fault zone, metamorphic rocks