Prediction and significance of intra-platform shoals distribution of Changxing formation in Gaoshiti area of Sichuan Basin

Sedimentary Facies, Paleogeography, and Depositional Models of the Middle–Late Permian in the Sichuan Basin, Southwest China

“…Sedimentary facies refer to the similarity and consistency exhibited by various sediment properties, composition, and structure within a specific time and space range [26,30]. By closely examining the profiles and rock samples from corresponding strata in areas such as Guangyuan and Jiange, factors such as color, lithology, texture, composition, and structure were analyzed to preliminarily determine the sedimentary facies types.…”

“…The erosion of the Maokou Formation, along with the constraints imposed by the Wujiaping Formation, suggests that prior to the Emeishan basalt eruption, a rapid crustal uplift formed a significant dome uplift [7,9]. Consequently, the structural pattern of the Sichuan Basin exhibits higher elevations in the southwest and lower elevations in the northeast [10,26]. Owing to variations in tectonic patterns, sedimentary facies within different regions during the same period display substantial differences, ranging from river delta facies to deepwater shelf facies [21,25].…”

“…Through the identification and analysis of rock samples and thin sections, eight macroscopic facies and fourteen microfacies were identified and described from the sections on the matrix type, particle composition, and structural characteristics of the rocks [21,23,26].…”

“…Based on previous studies [1,[24][25][26][27]30] on the Permian sedimentation in the Sichuan Basin, field observations from outcrop measurements and relevant drilling core examinations, and the integration of well logging data, we conducted a detailed subdivision of the Permian facies in the Sichuan Basin. This subdivision encompasses various sedimentary facies and subfacies types based on criteria such as lithology, sedimentary structures, fossil assemblages, and well logging response patterns.…”

“…Open platform facies are generally located on the seaward side of the platform, often between the platform margin and the restricted platform, separated from the open sea by underwater uplifts [23,26]. They are characterized by a broad marine area, relatively flat seafloor topography, well-developed water circulation, normal salinity levels, and water depths ranging from a few meters to tens of meters.…”