【作者】 任东； 卢立伍； 姬书安； 郭子光； 尹继才； 韩迎健；

【Author】 Ren Dong;Lu Liwu;Ji Shuan;Guo Ziguang;Yin Jicai;Han Yingjian;Geological Museum of China;

【机构】 中国地质博物馆；

【摘要】 燕辽地区的中侏罗-早白垩世地层中共有3个动物群贯穿始终,即燕辽动物群、热河动物群、阜新动物群,分别分布于中侏罗世、晚侏罗世及早白垩世,构成多门类化石群的组合序列。根据以昆虫为主的动物群组合序列研究,可以推测中侏罗世燕辽地区处于温带气候条件下,森林沼泽发育,分布广,但水面规模不大,水体不深,地形起伏差异较小,而晚侏罗世该区地形起伏较大,高山可达800--2000m,水面宽,水体探,适于大型鱼类活动,气候与中侏罗世相似,陆地植被茂盛,森林极为广布。到早白垩世尼欧克姆期,动物群的种类相对较贫乏,以陆生昆虫为主,出现的昆虫大多为典型亚热带昆虫,说明该地气候仍偏热,但湖泊显著减少,已逐渐向干燥的气候过渡。从昆虫类及其他一些化石的古地理分布特征分析,可以作出如下推断,即:劳亚大陆或欧亚大陆与北美、非洲等大陆分离的最后时限不会早于中侏罗世,以后随着泛大陆解体,昆虫中一些类群(如蚊蝎蛉科等)的早期代表扩散到其他大陆,最终形成现今的分布格局。在这一过程中,第三纪白令陆桥虽有一定作用,但并不是主要和唯一的途径。更多还原

【Abstract】 Three fauna assemblages are recognised in Middle Jurassic-Early Cretaceous in Yanliao area(Hebei and Liaoning Provinces),North China,namely,Yanliao,Jehol and Fuxing Faunae,which are widely-distributed in Middle Jurassic,Late Jurassic Hnd Early Cretaceous respectively.According to the ecological study of the fossils in those faunae,mainly insects,fishes and reptiles,the paleoenvironment situation is briefly discussed as follows.In Middle Jurassic,Yanliao area was in the temperate region,and the forest and swamp widely distributed.The water is not very deep,small in size,and the landform is flat.But in Late Jurassic,the land morphology varied greatly,with flourishing continent vegetation,widely-distributed forest and high mountains 800-2000 m in height.The lake basin is deep and large in size which is favourable for middleu or largeu sized fishes.Up to Early Cretaceous Neocomian stage,the variation of fauna became decreased.Among the continent insects,most of them mainly lives in the subtropical area,which suggested that the weather became warmer.With the declining of lake,appears the dry climate.Incorporated paleogeographical distribution of the insects and some other fossils,it is probable that the splitting time of Laurasia(or the Euramerica) from North America(and Africa) is not as early as Middle Jurassic.Accompanying the breaku up of Pangea,some early representatives of insects in East Asia,such as bittacidae,was dispersed to the other continents,that formed the base of modern insect distribution.In this process,the Tertiary Bering Bridge was not the main or unique passway,though it still is important for the dispersal of the animals between the continents since the Late Cretaceous.更多还原