Stratigraphic Sequences And Basin Characteristics Of Xibiehe Formation In Zhurihe,Inner Mongolia

In order to solve the attribution of the Xibiehe Formation and the division of strata,by means of the regional Geology mapping,identification of rock flakes,clastic rock composition analysis,zircon U-Pb isotope dating and other methods in Zhurihe,Inner Mongolia,the strata of the formation are analyzed and discussed in terms of lithologic facies,stratigraphic sequence,sedimentary facies and sedimentary environment,stratigraphic age,provenance and tectonic setting,and basin properties.Through the field observation and the identification of the rock,the formation lithology is dominated by clastic rocks with a small amount of carbonate rocks.The clastic rocks are mainly conglomerate,sandstone and slate;the carbonate rock is bioclastic limestone.The youngest zircon age is 392.76±2.70 Ma,and the zircon age of the intrusive rock is 191.49±5.50 Ma.Combined with the study of the paleontological fossils,the Xibiehe Formation era is included Late Silurian-Early Devonian.Through the analysis of the lithofacies,it is divided into conglomerate,sandstone,mudstone and carbonate.It is divided into LSC1 and MSC1?4 by high-resolution sequence stratigraphy.The first member belongs to alluvial fan facies deposition,and is further divided into fan root,middle and margin.The second member belongs to the intertidal subfacies and lagoon mud subfacies.The Dickinson method and Rock flake identification are used to analyze the debris components of the sandstone.The sandstone in the first member is from the volcanic island arc source area and the sandstone of the second member comes from the source area of the recirculation orogenic belt.Based on the results of lithologic facies,sedimentary facies,zircon age and tectonic setting of the source area,it is considered that the study area is a rift-type basin in the Late Silurian-Early Devonian period.From the turbulent environment to the gradual stabilization,the basin experienced an evolution from the intracontinental rift to the passive continental margin in the study area.Figure 18;Table 13;Reference 64...