## 6 Conclusions  
1. The organic matter abundance of the hydrocarbon source rocks of the Permian Qipan Formation in the piedmont of southwestern Tarim Basin was evaluated as medium-good hydrocarbon source rocks. The hydrocarbon source rocks are mature, with the  
Figure 16: Identification map of paleosalinity. (**a**) Scatterplot of TOC content versus Sr/Ba. (**b**) Scatterplot of TOC content versus B/Ga.  
Figure 17: TiO\({}_{2}\) and Al\({}_{2}\)O\({}_{3}\) correlation indicator map. (**a**) P\({}_{1-2}\)\(q\) in Qimeigan section. (**b**) P\({}_{1-2}\)\(q\) in Paojianggou section.  
Figure 15: (**a**) The relative proportions of SiO\({}_{2}\), Al\({}_{2}\)O\({}_{3}\), and CaO were determined by triangulation. (**b**) The relative proportions of TOC, S, and Fe were determined by triangulation.  
organic matter having reached a stage of high or over-mature evolution. The koregen types are predominantly Type III, Type II\({}_{2}\), and a portion Type I.
2. The sedimentary waters of the hydrocarbon source rocks of the Permian Qipan Formation in the piedmont of southwestern Tarim Basin are predominantly oxygen-rich, with a lesser degree of anoxia. The salinity of the water bodies is comparable and high in semi-saline environments. The detrital material that formed the hydrocarbon source rocks of the Qipan Formation was derived from an unstable source and originated from an amphibolite environment. This also indicates that the organic matter types of the hydrocarbon source rocks of the Qipan Formation exhibit differences depending on the depositional environment.
3. The type of organic matter present in the hydrocarbon source rocks varies due to differences in the depositional environments. The depositional environments in the vicinity of Wuqia County are predominantly marine, comprising open continental shelf facies, slope facies, and shore facies. The organic matter present is predominantly Type I, with a minor component Type II. In the vicinity of the Qiemugan section in the northwestern of the Kashi sag, the lagoon facies, the shore facies, and fan delta facies are developed. The organic matter is mostly of mixed source, mainly of Type II. In addition to marine environments such as lagoon facies and shore facies, the southwestern part in the piedmont of southwestern Tarim Basin also developed sea-land transitional phase deposits such as fan deltas facies and barrier facies. Influenced by terrestrial sources of organic matter, Type II and some Type III organic matter were formed.  
Conceptualization, L.Y. and G.Z.; methodology, J.Y.; software, G.Z.; validation, G.Z. and Q.W.; formal analysis, Q.W.; investigation, L.Y.; resources, Z.W.; data curation, Q.W.; writing--original draft preparation, Q.W.; writing--review and editing, Q.W.; visualization, Q.W.; supervision, Z.W.; project administration, Z.W.; funding acquisition, Z.W. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The data presented in this study are available on request from the corresponding author.  
Exploration and Author [PERSON] was employed by the company Development Research Institute of PetroChina Changqing Oilfield Company. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.