摘要
白垩系青山口组到嫩江组沉积时期 ,松辽盆地为深水坳陷湖盆 ,沿长轴方向为缓坡 ,而在短轴方向为陡坡。缓坡条件下 ,三级层序界面表现为沉积相带的迁移 ,地震剖面上的超削反射终止特征不明显 ,陡坡条件下 ,三级层序界面不仅表现为沉积相带的迁移 ,而且在地震剖面上的超削反射终止特征十分明显。在层序内部均可识别出低位域、水进域和高位域。在层序的低位域 ,沿盆地长轴方向 ,三角洲水下分流河道十分发育 ,在河口的前方形成分布较广、相对较薄的河口坝、远砂坝沉积及湖底扇 ;沿短轴方向 ,三角洲水下分流河道不发育 ,而发育河口坝和远砂坝 ,向湖区方向 ,过渡为前三角洲和深湖沉积 ,在前三角洲和深湖沉积区发育大量重力流成因的湖底扇。
During the depositional stage of Cretaceous Qingshankou, Yaojia and Nenjiang Formation, Songliao basin was a depression lake with deep-water, the slope of the basin was gentle along the long-axis, and was steep along the short-axis. The migration of depositional facies is characteristics of the third-order sequence boundary in gentle slope, but the onlap and truncation in seismic profile is not clear. In the steep slope, the third-order sequence boundary displayed as migration of depositional facies, but the onlap and truncation in seismic profile is very clear. The LST, TST and HST can be recognized in the third-order sequence. Along the long-axis, the distributary channel of delta developed very well, but mouth-bar, distal-bar and lake-floor-fan sediments are thin. Along the short-axis, mouth-bar, distal-bar and lake-floor-fan sediments developed in order along the lake-direction, but lack of the sediments from distributary channel of delta.
出处
《沉积学报》
CAS
CSCD
北大核心
2004年第3期387-392,共6页
Acta Sedimentologica Sinica
基金
国家自然科学基金项目 (批准号 :40 2 72 0 57)
国家重点基础研究发展规划"973"项目 (G1 9990 4 33)资助
关键词
沉积模式
坳陷深水湖盆
沉积相
地震剖面
三角洲
framework of sequence stratigraphy, lowstand system tract, depositional model, depression deep-water lacustrine basin, Songliao basin
