孙吴-结雅盆地沉降-隆升演化史分析

Analysis of subsidence-uplift evolution history of Sunwu-Zeya Basin

位于松辽盆地东北部的孙吴-结雅盆地是横跨黑龙江的中、新生代断坳叠置型陆相残留盆地,具有良好的油气前景,目前实际油气勘探程度较低。为揭示该地区中、新生代盆地的构造及演化特点,笔者在孙吴-结雅盆地3个主要断陷内,利用4口钻井资料进行了地层的精确划分与对比,恢复各时代地层的沉降-隆升史曲线。研究表明,自晚侏罗世晚期形成以来,盆地经历了3次沉降和2次隆升。盆地所经历的2次较大规模的隆升年代分别为103.4~93.9 Ma和42.3~23.0 Ma(北部为33.9 Ma),其后期隆升时间明显长于前期,隆升幅度也大于前期。盆地的主体沉积形成时间为109.8 Ma。孙吴-结雅盆地的形成与演化经历伸展断陷、构造反转、整体坳陷、晚期反转和差异升降等5个阶段,造就了现今盆地的下断上坳、隆坳相间的盆地基本构造结构和格局。

The Sunwu-Zeya Basin,located in the northeast of the Songliao Basin,is a Meso-Cenozoic terrestrial residual basin superimposed depression-fault depression across the Heilongjiang River.It has good oil and gas prospects,while the degree of oil and gas exploration is relatively low.In order to reveal the tectonic and evolutionary characteristics of the Meso-Cenozoic basins in this region,the authors used four drilling data from three major fault depressions in the Sunwu-Zeya Basin to precisely divide and compare the strata,and to restore the subsidence-uplift evolution history curves in different ages.The study shows that the basin has experienced three subsidence and two uplift events.The two large-scale uplifting events of the basin took place at 103.4-93.9 Ma and 42.3--23.0 Ma(33.9 Ma in the north),respectively.The later uplifting is significantly longer in time and greater in amplitude than those of the earlier one.The main sedimentary formation time of the basin was 109.8 Ma.The formation and evolution of the Sunwu--Zeya Basin can be divided into five stages:extensional faulting,structural inversion,whole depression,late inversion and differential uplift-subsidence,resulting in the basic structure and pattern of the present basin,which is characterized by lower faulting-upper depression and depression interleaved uplift.