Palynological Evidence for Paleoclimate and Vegetation in the Lower Jurassic Sangonghe Formation, Hoxtolgay Basin, Northern Xinjiang, Northwest China

ABSTRACT The Lower Jurassic Sangonghe Formation is an important source rock in the Hoxtolgay Basin, northern Xinjiang, northwest China. This study explores the palynological characteristics of the formation, aiming to determine its geological age and reconstruct the paleoclimate and paleovegetation based on palynological data. A total of 20 palynological samples were collected from the dark grey mudstone of the 223.8–686.4 m interval in HD1 well. The samples were analysed to identify palynological fossils and establish a palynological assemblage. The analysis identified 178 species from 60 genera of spores and pollen, establishing the Deltoidospora‐Osmundacidites‐Cycadopites (DOC) Assemblage. Pteridophyte spores dominated (62.7% on average), with trilete laevigate spores being the most abundant (47.1%), followed by apiculate spores (11.6%), and lesser amounts of cingulate, murornate, and monolete spores. Gymnosperm pollen accounted for 35.9%, with monosulcate pollen being the most prevalent (23.9%). The palynological assemblage indicates that the geological age of the Sangonghe Formation is Pliensbachian‐Toarcian (Early Jurassic), and the reconstructed paleovegetation suggests a subtropical humid climate. This study provides important geological insights, supporting the potential for oil and gas exploration in the region.