燕辽地区晚中生代动物君及其古生态和古地理意义 |
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关键词:Jurassic-Cretaceous fauna assemblage paleogeography paleoeoclogy |
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Late Meozoic Fauna Assemblages of Yanliao Area, North China, and Its Paleoecological and Paleogeographical Significance |
Three fauna assemblages are recognised in Middle Jurassic-Early Cretaceous in Yan-liao 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 distribut-ed The water is not very deep, small in size, and the landfrom is flat. But in Late Jurassic, the land morphology varied greatly, with flourishing continent vegetation, widely-distributed forest and high mountains 800-2000m in beight The lake basin is deep and large in size which is favourable fro 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 Eu-ramerica) 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 te animals between the continents since the Late Cretaceous. |
Ren Dong,Lu Liwu,Ji Shuan,Guo Ziguang,Yin Jicai,Han Yingjian.1996.Late Meozoic Fauna Assemblages of Yanliao Area, North China, and Its Paleoecological and Paleogeographical Significance[J].Acta Geoscientica Sinica,17(z1):148-154. |
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