松辽盆地断陷末期反转构造特征与形成机制

通过对地震勘探资料的解释和分析，本文将松辽盆地断陷末期的构造反转样式划分为地层反转、断层一地层反转和地层掀斜三种类型。断陷末期构造反转活动对徐家圈子断陷、梨树断陷等影响较大，形成了背斜、逆断层等反转变形构造；对于其他断陷则主要是造成地层掀斜。本文采用层长不变、面积守恒原则，对解释剖面进行了二维平衡恢复。通过分析认为，构造反转活动开始于早白垩世沙河子期末，结束于早白垩世营城期末，其结果导致了松辽盆地断陷期的结束、区域隆起和剥蚀。通过对区域构造应力场和地球演化节律特征的分析，本文探讨了断陷末期反转构造的形成机制，发现该期构造反转活动的区域构造应力场最大压应力方向为北东东一南西西向，地幔隆起的衰减和回落导致脆性地壳产生挤压应力，形成相应的收缩反转构造。

Characters of reverse tectonics and its forming mechanism in late of fault depression in Songliao basin.

Through interpretation and analysis of recent seismic exploration data,the reverse tectonics styles in the late of fault depression in Songliao basin can be divided into three kinds:the reverse tectonics,the fault reverse tectonics and the lift decline tectonics.The reverse tectonics activity in the late of fault depression had big influence on Xujiaveizi fault depression and Lisu fault depression,which formed reverse deforming structures such as anticline and reverse fault;but its influence on other fault depression mainly resulted in lift decline tectonics.Adopting the principle of unchanged layer length and areal conservation,the 2 D balanced restoration can be done for interpretation sections,after that,we considered that the reverse stage began the late of Kimaeridgian stage and ended at the late Ryazanian stage,resulted in making an end of fault depression in Songliao basin and in denudation because of uplift of the region.The analysis of regional tectonic stress field and of characters of earth evolution,the paper discussed the forming mechanism of inversed structure at the late of fault depression and discovered that the maximum stress direction of regional tectonic stress field resulted in reverse deformation was NEE-SWW,and the slowed and declined uplift of earth mantle resulted in squeeze stress in fragile crust,forming related shrinking reverse tectonics.