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延庆千家店盆地土城子组底部不整合接触蓟县系雾迷山组,不见顶,主要分为3个岩性段,一段以复成分砾岩、砂砾岩为主;二段以紫红色、黑色薄层泥页岩和泥质粉砂岩为主;三段以复成分砾岩、含砾粗砂岩为主。前人在该盆地二段地层中发现大量动植物化石,有双壳类、叶肢介、昆虫、木化石、恐龙足迹等,但一直没有介形类、孢粉及恐龙化石的相关报道。在化石层位发现疑似“恐龙骨骼”化石,丰富了该区化石种类。通过LA-ICP-MS测年,得出一段底部年龄为157.62±0.69Ma;二段中上部年龄为157.13±0.96Ma。分析认为,千家店盆地土城子组主体沉积时代为晚侏罗世早期,在前人研究的基础上,通过多样的古生物化石来探讨该盆地古气候背景及沉积环境。
The unconformity at the bottom of Tuchengzi Formation in the Yanqian Qijiadian basin is not related to the Jishan Member of the Wumishan Formation in Jixian, and is mainly divided into three lithologic segments, with a section of conglomerate and conglomerate. The second segment is mainly composed of fuchsia and black thin Pale shale and argillaceous siltstone are the main parts of the third member. The third member is composed of complex conglomerate and gravel coarse sandstone. Previously, a large number of animal and plant fossils were found in the second member of the basin, including bivalves, leaf extremities, insects, wood fossils, and dinosaur footprints. However, there have been no reports of ostracods, sporopollen and dinosaur fossils. Found in the fossil layer suspected “dinosaur skeleton ” fossil, enriched the area fossil species. By LA-ICP-MS dating, a section of the bottom of the age was 157.62 ± 0.69Ma; second middle and upper age was 157.13 ± 0.96Ma. The analysis shows that the main depositional age of the Tuchengzi Formation in the Qianjiadian basin was Early Jurassic, and on the basis of previous studies, the Paleoclimatic paleoclimatic background and sedimentary environment were discussed through various paleontology fossils.