华北克拉通东部盆地白垩-古近纪构造沉降的时空变化及其与克拉通破坏的关系

白垩-古近纪为华北克拉通东部断陷盆地的形成时期，通过运用盆地分析技术，本次工作得到了这一时期各盆地的各阶段构造沉降曲线及相应的构造沉降量和沉降速率。构造沉降分析表明，华北克拉通东部白垩-古近纪盆地的最强构造沉降峰期为古新世(孔店期)，次构造沉降峰期为早白垩世早期(莱阳期)。其中早白垩世早期为华北克拉通东部、南部盆地的最强构造沉降峰期，古新世为克拉通内部渤海湾盆地区的最强构造沉降峰期，而其它时期盆地的构造沉降特征表现为构造沉降峰期前后的弱沉降过渡阶段。结合盆地的分布规律，盆地的主要构造沉降中心在白垩纪集中在华北克拉通的南缘和北缘，而在古近纪则迁移到克拉通内部渤海湾地区，即由华北克拉通边缘向内部迁移。伸展期盆地的演化经历了宽裂谷(莱阳期)→窄裂谷(大盛期)→宽裂谷(孔店期)→窄裂谷(东营期)的循环演化模式，揭示了岩石圈的温度和强度的变化。而这种构造沉降的时空变化更支持华北克拉通破坏以拆沉机制为主。

Temporal?spatial changes of tectonic subsidence for Cretaceous?Paleogene basins in the eastern North China Craton and their relations with the craton destruction

Extensional basins were developed in the eastern North China Craton during Cretaceous to Paleogene. Tectonic subsidence curves，magnitudes and rates were obtained for each stages of the basin evolution by using the basin analysis method. The tectonic subsidence analysis shows that peak extension and tectonic subsidence for the Cretaceous?Paleogene basins in the eastern North China Craton occurred in Paleocene(Kongdian episode)，and the secondary subsidence stage happened in the earliest Early Cretaceous(Laiyang episode). The most intense tectonic subsidence for the southern margin of the eastern North China Craton took place in the earliest Early Cretaceous whereas it happened in Paleocene for the interior of the eastern North China Craton，i.e. the Bohai Bay Basin region. The tectonic subsidence of other stages between the peak subsidence times are characterized by weak and transition features. The tectonic subsidence analysis and basin distribution indicate that the tectonic subsidence centers concentrated in the southern and northern margins of the eastern North China Craton in Early Cretaceous while they migrated into the interior of the craton，i.e. the Bohai Bay Basin region，in Paleogene，showing migration from the margins to interior of the craton. The extensional basins experienced circle evolution from wide rifts(Laiyang episode)，narrow rifts(Daisheng episode)，wide rifts(Kongdian episode)to narrow rifts(Dongying episode). These indicate correspondent changes for lithospheric temperatures and intensity. The temporal?spatial changes of the tectonic subsidence support the delamination mechanism for the North China Craton destruction.