The Songliao Basin in Northeast Asia is the largest and longest-lived rift basin and preserves a near-continuous continental succession of the most of the Cretaceous period,providing great material to investigate the adaption of the terrestrial systems to the Cretaceous greenhouse climate and tectonic events.However,the paucity of precise and accurate radioisotopic ages from the Early Cretaceous strata of the Songliao Basin has greatly held back the temporal and causal correlation of the continental records to the global Early Cretaceous records.Three tuff layers intercalated in the Yingcheng Formation have been intercepted by the SK-2 borehole,which offer excellent materials for radioisotopic dating and cal-ibration of the chronostratigraphy of the Lower Cretaceous sequence of Songliao Basin.Moreover,the Yingcheng Formation recorded the largest and the last of the two major volcanic events in Songliao Basin,which also represents a turning point in the basin evolution history of Songliao from syn-rift stage to post-rift stage.Here we report high-precision U-Pb zircon geochronology by the CA-ID-TIMS technique on three tuff samples from the Yingcheng Formation of the SK-2 borehole in the Songliao Basin to con-struct a greatly improved,absolute age framework for the Yingcheng Formation and provide crucial age constraints for the Songliao Lower Cretaceous Strata.The new CA-ID-TIMS geochronology con-strained the Yingcheng Formation at 102.571+0.320/-2.346 Ma to ca.113 Ma,correlating to the Albian Stage.Combined with the previous published Songliao geochronology,the Quantou Formation is constrained to between 96.442+0.475/-0.086 Ma and 91.923+0.475/-0.086 Ma;the Denglouku Formation is constrained to between 102.571+0.320/-2.346 Ma and 96.442+0.475/-0.086 Ma;the age of the Shahezi Formation is estimated at ca.113 Ma to ca.118 Ma,which could extend to ca.125 Ma in some locations in Songliao Basin.The major unconformity between the Yingcheng Formation and the Denglouku Formation,which represents the transition of the basin from syn-rift to post-rift is thus confined to between 102.571+0.320/-2.346 Ma and 96.442+0.475/-0.086 Ma.This is roughly contemporaneous with the change in the direction of the paleo-Pacific plate motion from west-southwest to north or northwest in mid-Cretaceous,suggesting their possible connections.

Tiantian Wang;Chengshan Wang;Jahandar Ramezani;Xiaoqiao Wan;Zhiqiang Yu;Youfeng Gao;Huaiyu He;Huaichun Wu

State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences,Beijing 100083,China;Institute of Earth Sciences,China University of Geosciences,Beijing 100083,China;School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China;Department of Earth,Atmospheric and Planetary Sciences,Massachusetts Institute of Technology,Cambridge,MA 02139,United States;Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;College of Earth Sciences,Jilin University,Changchun 130061,China;School of Ocean Sciences,China University of Geosciences,Beijing 100083,China

地学前缘（英文版）

[1]Tiantian Wang;Chengshan Wang;Jahandar Ramezani;Xiaoqiao Wan;Zhiqiang Yu;Youfeng Gao;Huaiyu He;Huaichun Wu-.High-precision geochronology of the Early Cretaceous Yingcheng Formation and its stratigraphic implications for Songliao Basin,China)[J].地学前缘（英文版）,2022(04):89-97

Yingcheng,radioisotopic,ibration,chronostratigraphy,571+0,Quantou,442+0,923+0,Denglouku,Shahezi

High,precision,geochronology,Early,Cretaceous,Formation,its,stratigraphic,implications,Songliao,Basin,China,Northeast,Asia,largest,longest,lived,rift,basin,preserves,near,continuous,continental,succession,most,period,providing,investigate,adaption,terrestrial,systems,greenhouse,climate,tectonic,events,However,paucity,precise,accurate,ages,from,strata,has,greatly,held,back,temporal,causal,correlation,records,global,Three,tuff,layers,intercalated,have,been,intercepted,by,SK,borehole,which,offer,excellent,materials,dating,Lower,sequence,Moreover,recorded,last,two,major,volcanic,also,represents,turning,point,evolution,history,syn,stage,post,Here,report,high,Pb,zircon,CA,ID,TIMS,technique,three,samples,struct,improved,absolute,framework,provide,crucial,constraints,Strata,new,Ma,correlating,Albian,Stage,Combined,previous,published,constrained,between,estimated,could,extend,some,locations,unconformity,transition,thus,confined,This,roughly,contemporaneous,change,direction,paleo,Pacific,plate,motion,southwest,northwest,mid,suggesting,their,possible,connections

0.406312