关键词: 沉积微相, 古河流, 构造运动, 古气候, 控制

Abstract: By an analysis of drilling seismic and coredata,sedimentary processes of the 3rd and 4thmember of Cretaceous Quantou formation in the north-eastern part of Songliao basin can bedescribed with a deIta-plain facies model and 12 microfacies have been divided.An approachfor paleo-channel trend analysis was proposed,which leads to delineating the multiple-orderpaleochannel belts and discovered the paleo Songhua River during Quantuo period.System-atic diagrams of sedimentary environment and river trend have revealed that the base level(lake level) directly affected the paleochannel size while the deep faults and fault-block activities controlled the position and shift of paleo rivers respectively.Disposition of the sedimen-tary systems indicated that during 3rd and 4th stage of Quantou period the northern Songliaobasin might be an alluvial-lacustrine plain formed by the deposition of paleo-Nen,paleo-Songhua Rivers and their tributaries and distributaries.The paleo-Songhua River stretchedparallel with the present Songhua River.It might wind its way through Sanjiang basin andjoin into paleo-Heilong River.This discovery could be of significant importance for the oil-gas exploration and development in Songliao basin and its adjacent areas.

Key words: sedimentary microfacies, paleochannel, tectonic movement, paleoclimate, control