龙门山均衡重力异常及其对青藏高原东缘山脉地壳隆升的约束

青藏高原东缘处于不均衡状态，自西而东可分为青藏高原弱负均衡重力异常区、龙门山正均衡重力异常区和四川盆地负均衡重力异常区，表明该区的不均衡状态并未导致Airy均衡运动的产生，即龙门山没有均衡下降，而处于不断的隆升状态，显示该地区反均衡运动的构造抬升是导致龙门山隆升的主因。本次采用似三度体重力异常计算方法对该区的正均衡重力异常进行模拟和反演，研究了大尺度地貌分异与均衡重力异常分区之间的相互关系，结果表明，龙门山的下地壳顶面抬升了11．2～12．6km，造成了龙门山的正均衡异常，揭示了构造抬升和剥蚀作用在相似的时间尺度上和空间尺度上控制着龙门山地貌的形成，龙门山的表面隆升是构造隆升和剥蚀作用相叠加的产物。

Isostatic gravity anomalies in the Longmen Mountains and their constraints on the crustal uplift below the mountains on the eastern margin of the Qinghai-Tibet Plateau

The isostatic gravity anomalies on the eastern margin of the Qinghai-Tibet Plateau may be divided into the weak negative isostatic gravity anomaly zone of the Qinghai-Tibet Plateau, positive isostatic gravity anomaly zone of the Longmen Mountains and negative isostatic gravity anomaly zone of the Sichuan basin. The isostatic gravity anomalies did not cause Airy isostatic movements, i.e. no isostatic subsidence occurred in the Longmen Mountains but they were in a continuously uplift state, suggesting that the anti-isostatic tectonic uplift was the main cause responsible for the uplift of the Longmen Mountains. To understand the relationship between the formation of large-scale morphology and the isostatic gravity anomalies of the region, the authors simulated the positive isostatic gravity anomalies of the Longmen Mountains using the similar 3D body gravity anomaly computation method, and the inverse simulation results indicate the top surface of the lower crust below the Longmen Mountains has been uplifted for 11.2-12.6 km, thus causing the positive isostatic gravity anomalies zone of the Longmen Mountains. The authors draw the conclusion that the tectonic uplift and erosion controlled the formation of the morphology of the Longmen Mountains at a similar time and space scale.