纵弯叠加褶皱地区应力场研究-以川东北地区为例

川东北地区主体构造为北西向大巴山弧形构造带和北东-北东东向川东弧形褶皱带,发育早期北东向纵弯褶皱和晚期北西向纵弯褶皱,两者构成明显的纵-纵复合叠加,形成典型的限制褶皱、横跨褶皱、斜跨褶皱和移褶等。早、晚两期褶皱和共轭“X”节理均反映出早期应力场为北西-南东向水平挤压,晚期应力场为北东-南西向挤压。

RESEARCH ON THE STRESS FIELDS IN SUPERPOSED FOLD AREA --AN EXAMPLE FROM NORTHEASTERN SICHUAN

The Dabashan arcuate tectonic zone and the Chuandong arcuate folded belt constitute the main structures in the area of northeastern Sichuan. The superposed buckling folding occurred in the early-formed northeast-striking buckling folds and later-formed northwest-striking buckling folds, forming typical restricted fold, cross fold, obliquely cross fold and shifted fold. These two generations of folding and conjugate X-shaped joints indicate that the early stress field being NW-SE horizontal compression, and the later stress field NE-SW one respectively.