松辽盆地坳陷期T_2断层成因机制分析

ANALYSIS ON THE ORIGIN OF T_2 POST-RIFT FORMATIONS IN SONGLIAO BASIN

松辽盆地坳陷早期地层（登娄库－泉头组）中发育大量张性正断层，而尤以Ｔ２断层最发育。对Ｔ２断层剖面和平面特征及岩石变形机制的分析表明，Ｔ２断层是松辽盆地坳陷早期伸展作用的产物。首先是下部已有断层向上发展，同时在其两侧可能产生同向或反向伸展调节断层，到Ｔ２面沉积结束之后，伸展作用逐渐消失，断层发育亦趋于停止。

There are a large number of normal faults in the lower formations(from Denglouku to Quantou Formations).The typical ones are T2 faults that cut the T2 reflecting horizon(equal to the upper plane of Quantou Formation).Analysing the characteristics of T2 faults in section and plane and the mechanism of rock's deformation indicates that the origin of T2 faults dates back to the lithospheric extension in the early sagging of Songliao Basin.The faults which exist in lower formations would develop upward, meanwhile,some new adjusting faults occurred in both sides of it In either synthetic or antithetic way.When the stretching faded gradually after Quanton formation deposited,the faulting also stoped.