【摘要】 分析了四合屯含鸟化石沉积层的古生物组合、沉积环境及地球化学异常特征.研究表明,沉积物广泛发育水平层理,以泥岩等细碎屑为主,普遍含有火山碎屑物;剖面上的化石层可以划分3个化石组合,鸟化石产于中部组合;由于火山作用的影响,至少存在3次火山地震活动;湖面发生过3次规模较大的升降变化,火山活动造成了生物灾难性死亡;稀土元素δCe异常和多种微量元素异常揭示了古盆地环境的变化及其对生物界的影响.更多还原

【Abstract】 Based on the data of regional geological surveying and mapping in a scale of 1:50000 in Beipiao-Yixian district, Western Liaoning Province, the features of sedimentary environment are analyzed for the bird fossil-bearing beds in Sihetun area. They are as follows:(1)Horizontal beddings are widely developed in the sediment of mainly mudstone and fine-clastic rocks, with volcanic fragmental products.(2)The fossil-bearing beds can be vertically divided into three fossil assemblages,of which the middle assemblage contains fossil birds.(3)Due to the effects of volcanic activity, there exists at least three times of volcanic earthquakes.(4)The significant changes of lake surface level took place three times. The volcanic activities caused catastrophic biological death. (5) The anomalous δEu and δCe of REE and the anomaly of trace elements indicate the environmental change of the paleobasin and its influence on living nature. To sum up, the earth environmental changes provided evidence for the evolutive period and qualitative change of the Jehol Biota represented by precious fossils.更多还原