Abstract:

The Quantou Formation recovered by CCSDSKⅠs borehole (China Cretaceous Continental Scientific DrillingSongkeⅠthe south borehole) is 13207 m long and 100% of cores recovery. The sequence and process of lithologylithofacies and cyclic stratigraphy revealed by detailed core description. Nine rock types and three kinds of sedimentary facies including meandering river, shallow lake and delta front were recognized from the drilling core, there are ten sedimentary microfacies which are point bar, natural levee, crevasse splay, crevasse channel, floodplain, flood lake, subaqueous mouth bar, subaqueous inter distributary bay, mudstone of still water and turbidite. The Quantou Formation represents seventysix meterscale cycles (sixthorder cycle), twentyfive fifthorder cycles, eight forthorder cycles and two thirdorder cycles. Meticulously depicted(centimeter Level) continental red beds of the third and the fourth members of Quantou Formation will be a potential formulation profile for the studies on Cretaceous global oxygenenriched events. The reservoir sandstones of the third and the fourth members were developed basinwide as an inevitable product before the Songliao Basin was depressed or sagged with a large scale. The period of the third and the fourth members of Quantou Formation was a stage between developments of the fault basin and the sag basin with a large scale.

Key words:

Quantou Formation; sedimentary facies; sedimentary sequence; cyclic stratigraphy; CCSDSKⅠs; Songliao Basin