###### Abstract  
Seismic sedimentology and sequence stratigraphy, as emerging interdisciplinary fields, demonstrate unique advantages in characterizing seismic geomorphological responses of various system tracts within the stratigraphic frameworks of rift lacustrine basins. Focusing on the Paleogene Dainan Formation in the Gaoyou Sag of the Subei Basin, eastern China, this study integrates seismic termination patterns, sedimentary cyclicity analysis, and well-to-seismic calibration to subdivide the formation into three third-order sequences containing lowstand (LST), transgressive (TST), and highstand (HST) system tracts. The distribution of five distinct sedimentary facies exhibits pronounced sub-tectonic zonations controlled by the basin's architecture and structural evolution, with steep slope zones dominated by nearshore subaqueous fan-fan delta complexes, gentle slopes developing normal deltaic systems, and deep-semi-deep lacustrine facies with slump turbidite fans concentrated in depositional centers. Through a novel application of 90\({}^{\circ}\) phase adjustment, spectral decomposition, and multi-attribute fusion techniques, the relationship between seismic amplitude attributes and lithologies are established via seismic lithology calibration. Detailed sequence evolution analyses and seismic geomorphological interpretation systematically elucidate the spatio-temporal evolution of depositional systems within different system tracts in rift lacustrine basins, providing a novel methodological framework for sequence stratigraphic analysis in continental rift settings.  
equence stratigraphic framework; depositional systems; seismic geomorphology; Dainan Formation; the Gaoyou Sag; eastern China  
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<ccs2020> <concept>creating synergistic linkages between seismic stratigraphy and traditional sequence stratigraphic methods. This discipline capitalizes on the lateral continuity of 3D seismic data to extract high-resolution geomorphic signatures that directly inform depositional environmental reconstructions. Its two operational branches, seismic lithology and seismic geomorphology, serve complementary functions; the former converts seismic volumes into lithofacies distribution models while the latter translates geomorphic units into depositional systems through morphological diagnostics. The methodological toolkit integrates 90\({}^{\circ}\) phase rotation or shift, striatal slicing, frequency decomposition, RGB attribute blending, and geomorphic interpretation to quantitatively delineate the evolution of system tracts [7, 8, 9, 10, 11, 12].  
With the continuous improvement of resolution in 3D seismic imaging, modern seismic exploration has achieved enhanced capability in identifying complex sandbody geometry and conducting high-precision sedimentological interpretations. However, critical challenges persist during the transformation of seismic data into geological models, particularly regarding the accurate identification of reservoir structural units and the establishment of reliable verification criteria through analog analysis. Notably, when operating at sufficiently high resolutions, 3D seismic techniques enable precise spatial analyses of stratigraphic architecture, thereby providing robust constraints for constructing isochronous stratigraphic frameworks. The Dainan Formation of the Paleogene in the Gaoyou Sag serves as an exemplary case study, offering not only comprehensive geological datasets but also an ideal testing ground for seismic sedimentology methodologies. Building upon this technical foundation, this study employs a seismic sedimentology framework to systematically investigate the sequence stratigraphy characteristics of the Gaoyou Sag, a typical faulted lacustrine basin in eastern China. This integrated approach effectively combines the advantages of 3D seismic interpretation with lithostriagraphic analysis and depositional pattern recognition, establishing a novel perspective for deciphering the evolutionary processes of basin filling in rift lacustrine basins.