Late Cretaceous palynology and paleoclimate change:Evidence from the SK1(South) core, Songliao Basin, NE China  

作　　者：ZHAO Jing WAN XiaoQiao XI DangPeng JING Xia LI Wei HUANG QingHua ZHANG JinYan 

机构地区：[1]State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences [2]Exploration and Development Research Institute of Huabei Oil Field Corporation Ltd. [3]Guangzhou Marine Geological Survey [4]Exploration and Development Research Institute of Daqing Oil Field Corporation Ltd.

出　　处：《Science China Earth Sciences》2014年第12期2985-2997,共13页中国科学（地球科学英文版）

基　　金：supported by National Basic Research Program of China(Grant No.2012CB822002);National Natural Science Foundation of China(Grant No.41172037),China Geological Survey(Grant No.1212011120145);State Key Laboratory of Palaeobiology and Stratigraphy(Nanjing Institute of Geology and Palaeontology,CAS)(Grant No.123111);Fundamental Research Funds for the Central Universities(Grant No.2012011)

摘　　要：Cretaceous climate was warmer than today.The Songliao Basin contains one of the most important Late Cretaceous non-marine deposits in China for the research of the paleoenvironment and paleoclimate.This research is based on core samples from the SK1(S)borehole.The strata sampled are the upper part of the Quantou Formation to member 2 of the Nenjiang Formation,where spores,pollen,dinoflagellates,and other microfossils are abundantly preserved.Based on analysis of the spores and pollen fossils from the core samples,the following six fossil assemblage zones have been recognized in ascending order:The Cicatricosisporites-Cyathidites-Pinuspollenites,Schizaeoisporites-Cyathidites-Classopollis,Cyathidites-Schizaeoisporites,Schizaeoisporites-Cyathidites-Proteacidites,Proteacidites-Cyathidites-Dictyotriletes,and the Lythraites-Callistipollenites-Schizaeoisporites zones.The six fossil zones range from the late Cenomanian to early Campanian.The Late Cretaceous dinoflagellate cysts in the Songliao Basin are of high abundance and low diversity.Specific phytoplankton types reflect salinity changes of the Songliao Lake.Paleoecology of the dinoflagellates suggests that sediments of members 2 and 3 of the Yaojia Formation(K2y2+3)were deposited in a freshwater environment,whereas members 2 and 3 of the Qingshankou Formation(K2q2+3)and members 1 and 2 of the Nenjiang Formation(K2n1+2)were deposited in freshwater to brackish water environments.Combined with the paleoecology of dinoflagellates and the palynomorph biozones,valuable information of the paleoclimate was provided.The quantitative analyses of spores and pollen fossils,such as vegetation type,climate type,and humidity type,diversity and dominance,indicate a relatively sub-humid,mid-subtropical paleoclimate,with slight climatic fluctuation and/or temporal change.Cretaceous climate was warmer than today. The Songliao Basin contains one of the most important Late Cretaceous non-marine deposits in China for the research of the paleoenvironment and paleoclimate. This research is based on core samples from the SK1（S） borehole. The strata sampled are the upper part of the Quantou Formation to member 2 of the Nenjiang Formation, where spores, pollen, dinoflagellates, and other microfossils are abundantly preserved. Based on analysis of the spores and pollen fossils from the core samples, the following six fossil assemblage zones have been recognized in ascending order： The Cicatricosisporites-Cyathidites-Pinuspollenites, Schizaeoisporites-Cyathidites-Classopollis, Cyathidites-Schizaeoisporites, Schizaeoisporites-Cyathidites-Proteacidites, Proteacidites-Cyathidites-Dictyotriletes, and the Lythraites-Callistipollenites-Schi- zaeoisporites zones. The six fossil zones range from the late Cenomanian to early Campanian. The Late Cretaceous dinoflagellate cysts in the Songliao Basin are of high abundance and low diversity. Specific phytoplankton types reflect salinity changes of the Songliao Lake. Paleoecology of the dinoflagellates suggests that sediments of members 2 and 3 of the Yaojia Formation（K2y2＋3） were deposited in a freshwater environment, whereas members 2 and 3 of the Qingshankou Formation（K2q2＋3） and members 1 and 2 of the Nenjiang Formation（K2n1＋2） were deposited in freshwater to brackish water environments. Combined with the paleoecology of dinoflagellates and the palynomorph biozones, valuable information of the paleoclimate was provided. The quantitative analyses of spores and pollen fossils, such as vegetation type, climate type, and humidity type, diversity and dominance, indicate a relatively sub-humid, mid-subtropical paleoclimate, with slight climatic fluctuation and/or temporal change.

关 键 词：Late Cretaceous Songliao Basin spores and pollen DINOFLAGELLATE PALEOCLIMATE 

分 类 号：P534.53[天文地球—古生物学与地层学] P532[天文地球—地质学]