滇西北玉龙雪山隆升机制

THE UPLIFT MECHANISM OF MT. YULONG SNOW,NORTHWEST OF YUNNAN

通过对玉龙雪山东西两侧断层的系统研究 ,发现其东西两侧的断层均为倾向山内的逆断层。因此高耸的玉龙雪山是在主压应力方向为近东西向应力场作用下 ,沿双剪型逆冲断裂而迅速抬升的 ,而非前人认为的“地垒”

According to the literature, fractures in both sides of Mt.Yulong Snow dip toward the outer mountain except for Chubo-Baihanchang fracture.In other words, Shanghutiao (Upper Leaping Gorge) fault and Hutiaoshi (Tiger Leaping Gorge Stone) fault dip toward the west while Mt.Yulong Snow East piedmont fracture dips toward the east. For this reason, Mt.Yulong is considered to be formed by horst-uplifting as the mantle uplifted in the geological history. Based on the systematic study of fractures in both sides of Mt. Yulong Snow,we indicate that Chubo-Baihanchang fracture,Hutiaoshi fault and Shanghutiao fault in the western side dip toward the east and rised abruptly along a thrusted east piedmont fracture dips toward the west. Consequently,the high Mt. Yulong Snow rised abruptly along a thrusted double-shear fracture in an E_W oriented compressive stressfield developing in Tiassic,Paleogene, and Middle Pleistocene,rather than the horst-uplifted. The new mechanism is similar to that of Tianshan, which shows that the horizontal movement is more likely the main force source for the uplifting.