内蒙古海拉尔盆地白垩纪生物地层研究进展

ACHIEVEMENTS IN THE STUDY ON CRETACEOUS BIOSTRATIGRAPHY OF THE HAILAER BASIN, INNER MONGOLIA

兴安岭群龙江组产Ephemeropsistrisetalis等热河生物群分子,九峰山组产富含Cicatricosisporites,Pilosisporites,Concavissimisporites的孢粉组合,兴安岭群龙江组、甘河组火山岩同位素年龄为105-141Ma,证实兴安岭群的时代为早白垩世早期;扎赉诺尔群中以Cypridea,Limnocypridea,Ilyocyprimorpha和Hailaeria等属为代表的介形类动物群,以Nyktericysta,Vesperopsis等属为代表的NV浮游植物群,以富含Lygopodiaceae科各属孢子,尤其是Cicatricosisporites高含量的孢粉组合,代表了中国北方早白垩世特有的动、植物群面貌,而其中Asteropollis,Tricolpites和Polyporites等被子植物花粉化石的发现,这一事实似乎暗示了扎赉诺尔群的时代为早白垩世中、晚期;青元岗组产以Talicypridea,Altanicypris,Chinocypridea和Harbinia为代表的介形类动物群,具有显著的地域性特点,可与松辽盆地四方台组对比,其时代为晚白垩世Maastrichtian期。

This paper discussed the achievements in the study on Cretaceous biostratigraphy of the Hailaer Basin. The presence of a representative of the Jehol Biota, Epherneropsis trisetalis in Longjiang Formation, and abundant Cicatricosisporites, Pilosisporites and Concavissirnisporites in the Jiufengshan Formation, and the isotopic age 105-- 141Ma of volcanic rocks of the Longjiang and Ganhe formations, have demonstrated that the Xinanling Group is the Early stage of early Cretaceous in age. In the Zalainuoer Group, the fossil ostracoda fauna of Cypridea, Lirnnocypridea, Ilyocyprirnorpha and Hailaeria, the N-V Phytoplankton Group with Nyktericysta and Vesperopsis and abundant spores of Lygopodiaceae, especially the genus Cicatricosisporites dormlnant in content. They represent the distinct fauna and flora of Early Cretaceous in NE China. A few pollen of Asteropollis, Tricolpites and Polyporites occur in the Nantun Formation, it seems to imply that the age of Zalainuoer Group is middle--late of the Early Cretaceous. And the Qingyuangang Formation is characterized by the prosperous member Talicypridea, Altanicypris, Chinocypridea and Harbinia, which represent the fossil ostracoda fauna with distinct regional character, and may be correlated with the Sifangtai Formation of Songliao Basin, indicating their Maastrlchtlan age, Late Cretaceous.