NEW OBSERVATIONS OF THE INDOSINIAN MOVEMENT IN LIAONING

The Triassic strata in Liaoning may be divided into the Zhengjia Formation of the lower series, the Linjia and Houfulongshan formations of the middle series and the Laohugou Formation of the upper series. The intrusive rocks are divisable into three phases:the first phase is represented by diorites and gabbros-diabases, the second phase is represented by granites or porphyroid ademellites, and the third phase is represented by granites or medium- to fine-grained biotite adamellites. Besides, there are undivided alkaline rocks. According to the stratigraphy, intrusive rocks and contact relationships, the Indosinian movement in Liaoning may be divided into four phases. The first phase took place between the early and middle Triassic, represented by parallel unconformities between the Zhengjia Formation and the Linjia Lormation and expressed by the vertical movement. The second phase took place between the middle Triassic, represented by parallel unconformities between the Linjia Formation and the Houfulongshan Formation and expressed also by the vertical movement. The third phase took place between the nuddle and late Triassic, represented by angular unconformities between the Boufulongshan Formation and the Laohugou Formation and expressed by the horizontal movement; it is the main phase of the Indosinian movement in Liaoning. The fourth phase took place between the late Triassic and early Jurassic, represented by angular unconformities between the Laohugou Formation and the Kuntouboluo Formation and expressed also by the horizontal movement.