Abstract:
Development of sand bodies in the Shahejie Formation (SF) in the Jinzhou 27 Structure of the Liaodong Uplift in the northeast of Bohai Sea showed rapid lateral changes, thus conducting source tracing is of great significance for clarifying the distribution of sand bodies. By analyzing the zircon U-Pb age, zircon morphology, and debris composition of the sandstone in the study area, the age, type, and source area of the parent rock of the SF in the study area were clarified. Results indicate that: ① The SF mainly develops Cretaceous zircons with peak ages of 120 Ma and Paleoproterozoic zircons with peak ages of
1800 Ma and
2500 Ma. Zircons from the Cretaceous period are mostly columnar in angular shape with growth rings. The Paleoproterozoic zircons are mostly round in shape, with indistinct edges and corners, and their growth rings are often damaged. ② In the fourth member of SF, the proportion of Paleoproterozoic zircons in sandstone was 55%, and that of Cretaceous zircons was 25%. The rock fragments were mainly from metamorphic rocks. From the third to first and second members of SF sediments, the proportion of Paleoproterozoic zircons in sandstone was 44%, and that of Cretaceous zircons was 33%. The rock fragments were mainly from volcanic rocks and metamorphic rocks. ③ The parent rock of SF is mainly composed of Neoproterozoic sedimentary rocks in the northern part of Fuzhou in the Jiaoliao Uplift. At the same time, influenced by the continuously uplift of Liaodong Uplift, the influence of the provenance of Cretaceous volcanic rocks in the basin area gradually increased.