松辽盆地及其周缘地区石炭-二叠系构造体系与沉积特征研究

Study on Tectonic Systems and Sedimentary Characteristics of Permo-carboniferous in Songlioa Basin and Its Periphery

对深部构造进行重磁解释,松辽盆地及其周缘地区在中、下地壳以韧性变形为主,盆地区域内无褶皱,变形以稳定减薄为主,盆地具有克拉通属性。盆地及周缘基底异常明显,异常强度具有西强东弱、北强南弱的总态势。石炭-二叠系发育有三种构造体系类型:纬向构造体系、经向构造体系和华夏构造体系。从早石炭世到中二叠世时期,盆内及其周缘地区主要发育海相沉积环境,存在滨浅海相、滨海沼泽相及半深海相等。局部发育河流相、火成岩相、古陆。晚二叠世,主要发育陆相与湖泊相沉积。构造体系控制沉积相带的展布。西北部受到纬向和华夏构造体系共同控制,盆地隆起形成古陆,是主要的物源入口;南部和东部分别受到纬向和经向构造体系控制,形成东西向与南北向狭长的半深海相沉积。此外,盆地整体受到三大构造体系共同作用,主要接受了滨浅海相沉积,并在晚二叠世形成了一套三角形状的半深湖相沉积。

Through the interpretation of deep seated structure, the below and middle crust are mainly composed by ductile deformation in Songliao Basin and its periphery. It has no folds and the deformation thins steadily. The basin has the property of craton. The basement of the basin and its periphery is abnormal obviously. The tendency of abnormality is strong in the north and west, weak in the south and east. There are three types of tectonic systems in Permo--Carboniferous： latitudinal tectonic system, meridional tectonic system and Cathaysian tectonic system. From early Carboniferous to middle Permian, the basin and its periphery mainly develop marine sedmentary envi- ronment, such as seashore and shallow marine facies, seamarsh facies and bathyal facies. Local areas develop flu- vial facies, igneous facies and ancient land. In the period of Late Permian, the basin develops continental and la- custrine deposit. Tectonic systems can control the distribution of sedimentary facies. Northwest of the study area is controlled by latitudinal and Cathaysian tectonic system. The basin uplifts and forms ancient land, is also the main source of provenance. South and East part are controlled by latitudinal tectonic and meridional tectonic system. They form a narrow latitudinally--trending and longitudinal--trending bathyal facies deposition. In addition, the basin is combined affected by the three tectonic systems, and mainly develops shallow marine sediments. In the Late Permian, it forms a triangular shape of half deep lacustrine sedimentation.