松辽盆地西缘构造带构造格架、演化及油气资源潜力

Tectonic framework,evolution and potential petroleum resources of the structural belt in the western margin of Songliao basin

松辽盆地西缘构造带是研究松辽盆地形成演化的关键地带,但目前关于该构造带的构造格架、活动历史、控盆特征等仍不清晰,构造带深部物质架构及中—新生代构造演化的精细厘定为解决这一科学问题提供了新的证据。松辽盆地西缘地区布格重力异常与综合地球物理剖面特征指示,松辽盆地西缘构造带为区域上带状展布的超壳深大构造带。通过对综合构造变形带的产状、性质、运动学等资料分析,提出松辽盆地西缘构造带东西分带、倾向相背的“两带八字形”构造格架。依据构造带发育的基底背景、构造样式、地球物理特征等差异,建立了南北分段的“四段式”展布构架。在此基础上,结合区域构造演化、变形带构造解析与40Ar/39Ar构造年代学等资料,恢复了晚三叠世、中晚侏罗世、早白垩世中期、晚白垩世中期、古新世—渐新世和新近纪—更新世6期中—新生代构造活动年代格架。结合构造带的控盆作用指出,外盆带控制的中侏罗世和早白垩世中期沉积盆地是油气资源勘查的重要选区,为中国东北地区新层系油气资源勘查提供了新依据。

The structural belt in the western margin of the Songliao Basin is a key area for studying the formation and evolution of the Songliao basin.However,regarding the structural framework of this structural belt,the activity history and basin control characteristics are still unclear.This fine definition of deep material architecture and Meso-Cenozoic tectonic evolution in this structural belt provide a new evidence for solving this scientific problem.The Bouguer gravity anomaly and comprehensive geophysical profile characteristics indicate that the structural belt in the western margin of the Songliao basin manifests as a zonally distributed supercrustal deep structural belt.Through a comprehensive analysis encompassing the occurrence,nature and kinematics of the tectonic deformation zone,a"Bifurcated Dual Belt"structural framework is proposed.This framework divides into eastern and western zones,exhibiting opposing inclinations.According to the differences of basement background,tectonic pattern and geophysical characteristics of the structural belt development,a“four-stage”distribution framework is established for the north and south section.Additionally,considering the regional tectonic evolution,the structural analysis of deformation zones,and chronology data,the Meso−Cenozoic tectonic activity chronological framework of six periods is restored,including Late Triassic,Middle to Later Jurassic,middle Early Cretaceous,middle Late Cretaceous,Paleocene to Oligocene and Neogenic to Pleistocene.And combined with the basin-controlling influence of the structural belt,it is emphasized that the middle Jurassic and middle Early Cretaceous sedimentary basins,under the control of the exterior basin belt,hold paramount significance for the exploration,provided new basis for the exploration of petroleum reserves of new strata in northeastern China.