龙门山中段推覆构造的变形特征

论述了龙门山三大推覆体和推覆面的构造变形特征 ,认为耿达 -汶川推覆体为褶皱冲断推覆体 ,映秀 -白水河推覆体为冲断推覆体 ,彭灌推覆体为冲断褶皱推覆体 ,并将其划分为两个次级推覆体 ,而相应的推覆面分别为韧性变形为主叠加后期脆性变形 ;脆 -韧性变形以脆性为主及脆性变形的特征。其形成次序由北西向南东 ,即前展式扩张方式。主要活动时期为印支期和喜马拉雅期

Tectonic deformation of the nappe tectonic in the middle Longmen Mountains

The paper discusses the characters of tectonic deformation about the three big nappes and the decollement fault in the Longmen Mountains. It considers that the Genda Wenchuan nappe is a drape thrust one, the Yingxiu Baishuihe nappe is a thrust one, and the Pengxian Guanxian nappe is a thrust drape one. They are divided into two sub grade nappes in the paper. In correspondence with them, the decollement faults in order are a tenacity distortion with superimposing brittle one, a brittle tenacity distortion with the brittle distortion as the principal one, and a brittle distortion. Their formative order by EW SE is considered as the distension manner of piggyback propagation. Their main active periods are Indosinian and Himalayan stages.