Spore-Pollen assemblages of Xiu D 1 well in Xiushui basin, northern Liaon-ing Province and their stratigraphic singnificance

This paper discusses the sporo-pollen fossils collected from Xiu D1 well in Xiushui basin, northern Liaoning Province. Analysis, identification and systematic studies show that sporo-pollen from the depth 62.1~1089.7 m in Xiu D1 well can be divided in-to 3 assemblages. The upper assemblage (at the depth of 62.1~339m) is represented by genus Cicatricosisporites-Impardecispora-Pinuspollenites, and its geological age is early Cretaceous Valanginian-Hauterivian. The middle assemblage (381.5~699.3m) is represented by genus Densoisporites-Cicatricosisporites-Piceaepollenites, and its geological age is Early Cretaceous Berriassian. The lower assem-blage (703.85~1089.7m) is represented by genus Osmundacidites-Klukisporites-Podocarpidites, and its geological age is Late Jurassic Ti-thonian. The characteristics of 3 sporo-pollen assemblages can be compared with features of formations with sporo-pollen-containing assemblages, such as the Dabeigou Formation in the northern area of Hebei Province, the Lower Cretaceous Yixian Formation and the Jiufotang Formation in the western area of Liaoning Province, and the Lower Cretaceous Huoshiling Formation as well as the Shahezi Formation on the southeastern margin of the Songliao Basin. The determination of stratigraphic age of sporo-pollen-containing as-semblages is very important, which solves the stratigraphic division of column well and the correlation between stratigraphic column wells and regional strata. In addition, it provides detailed basic information for the study of regional stratigraphic paleontology.