中国西部新生代岩石圈汇聚和东部岩石圈离散的耦合关系与古环境格局演变的探讨

本文从印度大陆与亚洲大陆新生代碰撞前缘的多阶段构造变形与隆升过程,对比了我国南海北部大陆边缘盆地,东部渤海湾盆地的构造-沉积-岩浆事件,它们在时间上具准同时性,表现在两大陆碰撞构造变形和抬升的高峰时期正好与盆地伸展、拉张,快速构造沉降时期相对应;当构造转入相对稳定(松弛)阶段,表现为高原剥蚀夷平,岩浆活动频繁,盆地构造沉降速率减缓阶段.青藏高原多阶段构造-岩浆事件还与我国季风形成和发展以及全球新生代3次变冷事件具某种对应联系,认为深部地幔脉动上涌的热力效应可能是诱发高原季风,行星西风增强,高纬度降温的驱动力之一.它和高原地形增高引发大气热机效率增大起着互补作用,使青藏高原成为诱发我国大气环流变化的启动区.

COUPLING OF THE LITHOSPHERIC CONVERGENCE OF WEST CHINA AND DISPERSION OF EAST CHINA IN CENOZOIC: LINK WITH PALEOENVIRONMENTAL CHANGES

Analyses of deformation, sedimentation and magmatism in the continental marginal basins of the northern South China Sea and the Bohai basin in North China in Cenozoic indicate a penecomtemporaneous process with multi-stage deformation and raising of the Tibetan plateau since the collision of India with Asia. Intense deformation and uplifting of Tibet concurred with extension and rapid tectonic subsidence in the study basins. However, the relative tectonic silence and denudation in Tibet corresponds frequently to magmatic activity and slower subsidence in the basins. Furthermore, the multi-stage tectono-magmatic events of Tibet are also nearly synchronous with occurrence of the eastern Asian monsoon and of the three global cold events. These chronological coincidences suggest that thermal effect resulted from the collision-induced mantle upwelling and flow in the vertical and horizontal directions in Tibet might be one of the triggers for setting up the plateau monsoon, strengthening the planetary westerly winds and the cooling in high latitude of the Earth, as well as initiating the Asian monsoon.