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松辽盆地北部徐家围子断陷在伸展裂陷过程中,受板块构造和深部地质作用的影响,经历了一次挤压构造反转,其应力场特征也相应地发生了变化:火石岭期和沙河子期为NEE—SWW向拉张应力场,拉张应力逐渐加强,在沙河子期达到最大,沙河子末期受郯庐断裂左旋作用转为NEE—SWW向弱挤压应力场,营城期则为NEE—SWW向强挤压、NNW—SSE向弱拉伸应力场,登娄库期形成的应力场基本平息,进入重力均衡作用阶段。通过对区域应力场的变化特征分析认为,沙河子末期郯庐断裂左旋产生的应力场对徐家围子断陷形成近SN向延伸的“S”型构造格局具有重要的影响。
During the extensional rifting process of the Xujiaweizi Fault Depression in the northern part of the Songliao Basin, under the influence of plate tectonics and deep geologic features, the stress field characteristics of the Xujiaweizi Fault experienced a reversal of the compression structure. In the Shahezi stage, NEE-SWW tensile tensile stress field was applied and tension stress was gradually strengthened, reaching the maximum in the Shaheziju stage. At the end of the Shahezi subduction, The compressive stress field of NEE-SWW is strong and NNW-SSE is weak. The stress field formed in Denglou reservoir period is basically subsided and enters the phase of gravity equilibrium. Through the analysis of the changing characteristics of the regional stress field, it is considered that the stress field produced by the left-hand rotation of the Tan-Lu fault in the late Shahezi sub-period has an important influence on the “S” -type tectonic pattern of the Xujiaweizi faulted depression formed near SN.