内蒙古东南部开鲁盆地晚白垩世嫩江组孢粉植物群

LATE CRETACEOUS PALYNOFLORA FROM THE NENJIANG FORMATION IN THE KAILU BASIN,SOUTHEASTERN INNER MONGOLIA,CHINA

开鲁盆地白垩系发育,至今已有200余口探井钻遇到上白垩统,其中嫩江组滨浅湖相沉积地层厚度稳定,分布广泛,含较丰富的孢粉化石。通过对嫩江组孢粉化石的系统研究,建立了以Schizaeoisporites-BeaupreaiditesLythraites为代表的孢粉组合。孢粉组合和岩石组合的对比表明,开鲁盆地缺失松辽盆地嫩江组中上部地层。根据沉积特征和孢粉植物群面貌,对古植被、古气候和古环境进行了讨论,认为本区晚白垩世处于东北中生孢粉植物区南缘,孢粉植物群具有过渡性质,反应了偏干的暖温带—亚热带气候特征。

The Cretaceous strata in the Kailu Basin,has been disclosed by more than 200 wells drilled in the Upper Cretaceous Nenjiang Formation, with wide-distributed, fossil-rich, stable-thickness near shore shallow lake sedimen- tary facies. Through the systematic study of the sporopollen fossils of the Nenjiang Formation, we established the sporopollen assemblage represented by Schizaeoisporites^Beaupreaidites-Lythraites. Comparing the sporopollen as- scmblages and the rock assemblages, the Kailu Basin is found to be lack of the middle-upper Nenjiang Formation stra- ta in the SongIiao Basin. According to the sedimentary characteristics and palynoflora, paleovegetation, paleoclimate and paleoenvironment are discussed in this paper. The Late Cretaceous of the Kailu Basin in the south margin of the northeastern Mesopalynofloristic region, with transitional sporopollen flora, has a partial dry warm temperate-- sub- tropical climate characteristics.