松辽盆地白垩系综合年代地层学研究新进展

生物地层学研究表明,火石岭组、沙河子组和营城组均产Cicatricosisporites,Klukisporites,Densoisporites和Aequitriradites等早白垩世代表分子,登娄库组产Cicatricosisporites exilis-Hymenozonotriletes mesozoicus...

NEW PROGRESS OF INTEGRATED CHRONOSTRATIGRAPHY OF THE CRETACEOUS IN SONGLIAO BASIN

Cicatricosisporites,Klukisporites,Densoisporites and Aequitriradites were obtained from the Huoshiling,Shahezi and Yingcheng formations.Thesesporopollen fossils are characteristic of Early Cretaceous strata in the world.The Cicatricosisporites exilis-Hymenozonotriletes mesozoicus assemblage is recovered from the Denglouku Formation.This assemblage is typical flora of the Albian in North China.This assemblage also contains Kraeuselisporites majus,Scopusporis lautus,and Balmeisporites holodictyus,which are characteristic of Albian strata in North America and Australia.Abundance angiosperm pollen are obtained from the Quantou Formation,including Cranwellia striatella,Xinjiangpollis minutus,Lythraidites debilis,Quantonenpollenites crassatus,Q.tarimensis,Scollardia trapaformis,Beaupreaidites sp.,and Gothanipollis,indicating that the Quantou Formation may be of Cenomanian age.The U-Pb zircon ages of volcanic rocks indicate that the upper Huoshiling Formation(124.9±2.5 Ma) is of Barremian age,the Yingcheng Formation(zircon ages mainly105~112 Ma) of late Aptian-Early Albian age,the lower Qingshankou Formation(91.35±0.48 Ma) of Turonian age,and the lower part of the second member of the Nenjiang Formation(83.68±0.47 Ma) of Santonian age.Magnetostratigraphy shows a long term normal magnetozone from the Quantou Formation to the first member of the Nenjiang Formation,this magnetozone may be correlaed to the upper part of C34n.From the second to fifth member of the Nenjiang Formation,the magnetic polarity was reversed,and this interval can be correlated to chron C33r in the GPTS.The mixed magnetozone from the Sifangtai to Mingshui Formation can be correlated with polarity intervals C29r to C33n in the GPTS.