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对研究区志丹群作了详细划分,并与盆地内志丹群的划分和命名进行了统一。根据岩性、岩相和微体古生物组合上的显著差异,将原泾川组的上部红层单独划出建立一新的地层单位,称峰山组。此外,分别介绍了各地层单位中丰富的古生物资料和时代研究结论。根据介形类、轮藻的研究,确定峰山组的时代为早白垩世晚期,这在志丹群的时代研究上是一个重要的新进展。
The study area Zhidan group made a detailed division, and Zhidan group within the basin division and naming were unified. According to the significant differences in lithology, lithofacies and microfacies paleontology, the upper red beds of the original Jingchuan Formation were singled out to establish a new unit of strata, called Fengshan Formation. In addition, the rich paleontological data and age research conclusions of various strata units are respectively introduced. According to the study of Ostracoda and Chara, the age of the Fengshan Formation was determined to be early Cretaceous, which is an important new progress in the study of the age of the Zhidan Group.