Comprehensive Stratigraphic Analysis Of Tumen Group Of Neoproterozoic In Shandong Region

The distribution of Neoproterozoic stratum of Tumen group in Shandong Region is limited to the Anqiu-Juxian fault and its western area, the lithology is basically stable, a slight change between bottom and upper part. From bottom to top is divided into Heishanguan group,Erqingshan group, Tongjiazhuang group, Fulaishan group and Shiwangzhuang group. The study of Neoproterozoic stratum in Jiaoliaoxuhuai Region is relatively weak, it lacks reliable age control, biostratigraphy has a lot of controversy and progress in chemical stratigraphy is limited. In this case, the study of Neoproterozoic stratum in Shandong Region is relatively insufficient compared with that in Liaonan and Xuhuai Region.According to the predecessor data and measured section,with the study of biostratigraphy, event stratigraphy and chronostratigraphy,we use the multiple stratigraphic classification principle to study the age of the Tumen Group.At the same time, by comparing the biostratigraphy, event stratigraphy, Carbon and oxygen isotopes with Liaonan and Xuhuai Region, so as to provide more evidence for the specific time division of the Neoproterozoic stratum in the study region.Research shows: according to the comparative study of rock strata,biostratigraphy, event stratigraphy and measured section, it is concluded that the upper limit of the Tumen Group may be analyzed at 720Ma, which can be compared with the Neoproterozoic stratum in Liaonan and Xuhuai Region. The Neoproterozoic strata in Shandong area Region can be re-classified as Qingbaikou.After the carbon and oxygen experiments and correction, the main data are obtained as follows:Tangtou profile mainly includes Heishanguan group, Erqingshan group and Tongjiazhuang group. The δ13C range was -5.59‰—2.17‰, the mean value was 0.79±1.01‰.The overall has positive drift,after that there has negative drift trend.Fulaishan profile mainly includes Fulaishan group and Shiwangzhuang group. The δ13C range was-2.14‰—2.36‰; the mean value is 1.42±0.70‰.The whole has experienced a drift after drifting away from the three stages. The carbon isotopic change of the Tumen Group in Shandong is not significant,by analyzing the carbon isotopic characteristics of glaciers, there is the small trend of carbon isotope drif, and the overall trend is basically stable and the variation range is small. The curve trend is obviously different from glacial characteristics and glacial period in southern China. Belong to the glacial period before the start. There is a slight drift in the lower part of the Erqingshan Formation, which can be compared with the drift of the carbon isotope at the lower Changlongshan Formation in the lower part of Jixian Qingbaikou.The negative drift in the lower part of the floating hill group is related to the drift Comparison of carbon isotope negative drift in the upper well. The trend of carbon isotope variation in the Huaibei region is positive - negative - positive - negative - positive, and the carbon isotope of the soil is the same.The Neoproterozoic strata in Shandong area Region can be re-classified as Qingbaikou.