摘要
本文阐述了胶北地区的下元古界荆山群、粉子山群的构造特征。依据不同轴向的褶皱的叠压关系及同位素测年等资料,将胶北下元古界的主要构造变形分为三期:第一期:大致发生于2375Ma,以上覆岩系由北向南作顺层剪切为特征,形成新生的顺层面理和一系列显示强烈扁平化特征的小褶皱,沿底面形成大规模的具滑脱性质的韧性剪切带。第二期:发生于2171Ma 左右,由 NE—SW 收缩体制的作用,形成轴向 NW 的褶皱构造。第三期:发生于1800Ma 左右,由于自 SE 向 NW 的推挤,早期形成轴向 NE 的叠加褶皱,晚期则形成大规模的自 SE 向 NW 推覆的韧性剪切带。
This paper discusses the deformation characteristics of the lower proterozoic erathem in the northern Jiaodong region.Based on the different deformation mechanisms,the superposition relations of the fdds with different directions and isotopic ages,three deformation phases can be recognized in the lower proterozoic erathem in the northern Jiaodong region:(1)The first deformation is characterized by the beding-parallel ductile shearing of the overlying sequence from north to south and it occurred in 2375 Ma ago.(2)The second deformation occurred in 2171 Ma ago.It is characterized by the folds trending in the northwest direction.(3)The third deformation is characterized by the notheast trending superposed folds followed by a large ductile nappe shear zone and its age is probably 1800 Ma.
出处
《山东地质》
1993年第2期36-43,共8页
Geology of Shandong
