辽西地区义县组植物群古生态研究

    STUDY ON THE PALEOECOLOGY OF YIXIAN FORMATION IN BEIPIAO AREA, WESTERN LIAONING PROVINCE, CHINA

    • 摘要: 对产于辽西北票地区不同地点义县组二段湖相含珍稀化石沉积岩层中的植物化石时行了系统的总结研究.应用现代植物生态学的原理和方法,根据义县组植物群的组成特征和分类群生态学分析,研究了义县组植物群所反映的古生态特征,并划分出4个古植物群落.通过义县组植物群的叶相特征与现代不同气候带植被的对比,推断义县组时期的古植被面貌总体指示了亚热带-暖温带温暖湿润气候条件下的植被景观.同时,认为存在季节性干旱、半干旱气候条件.

       

      Abstract: The specimens of fossil plants studied in this paper are collected from the second member of Yixian for-matiom at different fossil locastibns in Beipiao area, Western Liaoning. The "feathered" dinosaurs, primitive birds, some reptilian and insect fossils as well as early angiosperm are from the sedimentary strata of laustrine facies(2nd member of Yixian F.). Applying the theory and method of modern phytoecology, the conditon of paleoecology shown by fossil flora are analyzed and discussed. Four fossil communities are set up based on the composition characters of flora and the analysis on the ecology of taxonomic group, i.e. (1) hygrophyte from intracoastal + calcophic vegetation in shallow water:Equisetites longevaginatus + Beipiaoa spinosa Community; (2) lowland-slow-slope:Tjrmia acrodonta + Co-niopteris burejensis Community; (3) intermontane upland:Liaoningocladus boii + Baiera borealis Community; and (4) xerophyte:Pagiophyllum + Gurvanella exquisite Community. By comparing the leaf feature between Yixian flora and modem vegetation in different climatic zones, the Yixian flora indicates a subtropic-warm temperate zone with warm wetness weather. At the same time, the occurrence of deciduous Ginkgoales represents a seasonal variation of the climate. The features of xerophilous Gnetales, Bennettiales with membranous leaves and Conifersles with scaled leaves may indicate a seasonal arid or semi-arid climate condition.

       

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