松辽盆地北部姚家组一段层序地层格架及形成机制

应用地震、测井、岩心及古生物等资料对松辽盆地北部白垩系姚家组一段层序地层格架进行了详细研究解剖。将姚一段地层分为3个四级层序,这3个四级层序呈退积式发育,底部与青山口组呈大型不整合接触,由此表明在姚一段沉积初期松辽盆地曾经经历了短暂的抬升作用,而后盆地又开始沉降、重新接受沉积,并且湖盆范围逐渐扩大。姚家组一段形成于87～88Ma,这一时期太平洋板块发生了一系列重组事件。通过对姚一段层序地层格架内部特征及其形成机制的分析,认为姚一段沉积时期,盆地已经开始了挤压作用。姚一段层序地层格架的形成是对这一板块重组事件的响应。

Analysis on the sequence stratigraphic framework and its forming mechanism of the first member of Yaojia Formation in the North Songliao Basin

A sequence stratigraphic framework is established for the first member of Yaojia Formation in northern Songliao Basin by using seismic,log,core and paleontologic data.Three fourth-order retrograding sequences are recognized in the first member of Yaojia Formation.They are in unconformable contact with the underlying Qingshankou Formation,indicating that the Songliao Basin experienced transient uplifting during the early deposition of the first member of Yaojia Formation before subsiding and receiving deposits once again and getting larger in lake basin area.The first member of the Yaojia Formtion was deposited in ca.88-87Ma when restructuring occurred in the Pacific plate.An analysis of the sequence stratigraphic framework and its forming mechanism demonstrates that compression initiated in the basin during the deposition of the first member of Yaojia Formation and its sequence stratigraphic framework was a result of this plate restructuring event.