松辽盆地南部梨树断陷正断层演化特征

Normal fault evolution in Lishu Fault Depression, southern Songliao Basin

邓铭哲 左宗鑫 邱岐 白帆

DENG Mingzhe ZUO Zongxin QIU Qi BAI Fan

中国石化 石油勘探开发研究院 无锡石油地质研究所, 江苏 无锡 214126 中国石化 石油物探技术研究院, 南京 211103

Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China SINOPEC Geophysical Research Institute, Nanjing, Jiangsu 211103, China

松辽盆地的形成受周缘构造带多方向、不同性质构造应力的影响，具有复杂的地质结构和盆地演化过程，位于松辽盆地南部的梨树断陷具有多种构造活动叠加复合演化的特征，是揭示周缘构造带活动过程及盆地构造—沉积响应的良好窗口，走滑构造活动是否控制了盆地沉积过程是长期以来未能解决的问题。利用三维地震数据开展精细解释，结合断距统计、构造模式分析等研究手段，对梨树断陷内桑树台断裂和秦家屯断裂早白垩世早期的伸展活动开展了研究。桑树台断裂演化过程受近东—西向伸展构造应力控制，断裂初始形成时规模较大，因而桑树台断裂受伸展方向调整影响较小；秦家屯断裂在下白垩统火石岭组沉积期受北东东—南西西伸展方向控制，下白垩统沙河子组沉积期受北东—南西伸展方向控制。梨树断陷早白垩世早期伸展活动和区域性走滑活动引起了伸展方向的变化。

The formation of the Songliao Basin was affected by multidirectional tectonic stress and various peripheral structural belts, and has a complicated geological structure and basin evolution process. The Lishu Fault Depression in the southern Songliao Basin has the characteristics of superimposed and complex evolution of multiple tectonic activities, and is a good window to reveal the impacts of the peripheral structural belts and basin tectonic-sedimentary response. Whether strike-slip tectonic activity controls the sedimentary process of the basin is an unsolved problem. Using three-dimensional seismic data to carry out detailed interpretation, combined with fault distance statistics, structural model analysis and other research methods, the extension activities of the Sangshutai and Qinjiatun faults in the Lishu Fault Depression during the Early Cretaceous were studied. The evolution process of the Sangshutai fault was controlled by the nearly east-west extensional tectonic stress. The initial scale of the fault was large, so the Sangshutai fault was less affected by the adjustment of the extension direction. The Qinjiatun fault was controlled by the NEE-SWW extension during the Early Cretaceous Huoshiling period, and by the NE-SW extension during the Early Cretaceous Shahezi period. The regional strike-slip activity in the Early Cretaceous extension in the Lishu Fault Depression caused a change in the extension direction.

国家科技重大专项 2017ZX05005-001-004;山东省自然科学基金 ZR2019BD0565

https://doi.org/10.11781/sysydz202102288