## 1 Introduction  
Foreland basins, recognized as one of the most prolific hydrocarbon provinces globally, are formally defined as elongate sedimentary depocenters developed upon continental lithosphere and paralleling the frontal margins of active orogenic belts [1; 2]. These basins exhibit distinctive asymmetric cross-sectional geometries, characterized by progressive deepening toward adjacent fold-and-thrust belts and gradual shallowing toward cratonic foreland regions [3; 4]. Their stratigraphic successions predominantly comprise erosional products derived from uplifted orogenic wedges, forming stacked elastic sequences with exceptional preservation potential [2; 4; 5; 6]. The unique tectono-sedimentary architecture, combined with favorable thermal evolution histories and efficient hydrocarbon trapping mechanisms, establishes foreland basins as critical components of global petroleum systems [2; 4; 7; 8; 2]. Global investigations of foreland basins have demonstrated that sedimentary processes fundamentally control reservoir-quality, source-reservoir configurations, and the predictability of favorable hydrocarbon play fairways [9; 10; 11; 12; 13; 14; 15]. In particular, depositional facies analysis serves as a fundamental prerequisite for petroleum exploration in such basins, providing essential constraints on spatial variations in reservoir heterogeneity, seal integrity, and hydrocarbon migration pathways. The temporal evolution of sedimentary systems within foreland basins further reflects dynamic interactions between thrust propagation, topographic loading, and climatic forcing, which collectively govern the development of stratigraphic traps and hydrocarbon charge efficiency [16; 17; 18; 19; 20; 21]. Petroleum enrichment belts are ubiquitously developed within global foreland basin systems, as exemplified by the Zagros Foreland Basin's Ghawar Field (hosting Jurassic-Cretaceous carbonate reservoirs) and the Sub-Andean Oriente Foreland Basin (featuring Cretaceous elastic petroleum systems) [22; 23; 24; 25; 26; 27]. Concurrently, large-scale natural gas accumulations within the Triassic thrust belts of the Kuqa Foreland Basin along the northern margin of the Tarim Basin in northwestern China collectively underscore the critical controlling role of foreland thrust belts on hydrocarbon enrichment [28; 29; 30; 31]. Extensive prior research on the Triassic succession of the Kuqa Foreland Basin emphasizes that detailed analysis of depositional models and source rock distribution patterns during this period is crucial for developing deeply buried petroleum resources [32; 33; 34]. The spatiotemporal evolution of depositional environments directly controls source rock quality, reservoir-seal configurations, and hydrocarbon migration pathways, thus constituting a key determinant of petroleum system efficiency. Previous investigations into the Triassic depositional systems of the Kuqa Depression have predominantly focused on the central Kelasu structural belt and the eastern Yangxia Sag. [PERSON] et al. inferred semi-arid to humid climatic conditions for the Triassic Kuqa area based on kerogen maceral composition, microfossil assemblages, and petrological characteristics, identifying the Taliqike Formation as a significant period of swamp development [29]. [PERSON] et al. analyzed over 20 wells utilizing lithological features, sedimentary structures, and paleontological evidence to propose a continental coarse-clastic coal-bearing stratigraphic sequence comprising, from base to top, alluvial fan, braided-river, meandering-river, and shallow to semi-deep lacustrine facies [35]. [PERSON] et al. delineated basin-wide facies distributions through integrated core observations and thin-section analyses, concluding that the northern Kuqa Depression transitioned south-north through fan-delta, fluvial-delta, shallow to semi-deep lacustrine, and coastal swamp environments [36]. [PERSON] et al.