## 4 Results
### Restoration Results of Graben Denudation in Changling Formation
This formation experiences the most substantial denudation among the four targeted strata, with the remaining strata thickness varying from 0 to 1800 m across the  
Figure 10: Denudation thickness map of the Huoshiling–Denglouku Formation in Changling Graben. Notes: (**a**) Huoshiling Formation; (**b**) Shahezi Formation; (**c**) Yingcheng Formation; (**d**) Denglouku Formation. area. The denudation thickness within the Shahezi Formation itself spans from 0 to 750 m, with an average thickness of approximately 300 m.  
Shaped by the faulting patterns of the depression, the strata from the graben period have evolved in a continuous sequence, yet the extent of denudation varies significantly across the basin's regions. The central trough experiences the most intense denudation. Analysis of the denudation characteristics of both the Huoshiling and Shahezi Formations indicates that during the Shahezi Formation's depositional phase, the Shenzijing and Hashituo areas were part of a symmetrical dual-fault structure, which initially formed a unified lake basin. This basin was later segmented by compressive tectonic forces towards the end of the Shahezi period, leading to extensive denudation. The residual thickness of the Huoshiling Formation ranges from 0 to 1200 m, with the most significant denudation, estimated at around 417 m, occurring in the Shenzijing-Hashituo region. The denudation intensity is most pronounced in the central areas, tapering from north to south, with the denudation thickness primarily oriented in a north-south direction. (3) Denudation characteristics of Yingcheng Formation  
The eroded strata of the Yingcheng Formation exhibit a thickness range from 0 to 450 m, with an average of approximately 100 m (as shown in Figure 10c). The overall pattern of denudation is similar to that observed in the Huoshiling and Shahezi Formations, with the central trough undergoing the most severe denudation. Notably, the degree of denudation in the Qianbei Trough has increased compared to the earlier two periods. The thickness of the remaining strata ranges from 0 to 2400 m.  
(4) Denudation characteristics of Denglouku Formation  
The eroded strata of the Denglouku Formation exhibit a thickness range from 0 to 280 m, with an average thickness of approximately 120 m (as illustrated in Figure 10d). Within the Qianbei Trough, the erosive forces during the Denglouku epoch were significantly intensified. This epoch is characterized by a more distinct overall uplift, which has led to a significant broadening of the denudation boundaries across the basin. Despite this, the total denudation within the basin remains comparatively modest. The Denglouku Formation signifies a pivotal transition from a fault depression to an uplift phase, and by the conclusion of the Denglouku depositional period, a tectonic inversion event took place, causing a surge in denudation along both the eastern and western flanks. The stratigraphic trend extrapolation method offers the advantages of speed and intuitiveness in denudation restoration, enabling the reconstruction of stratigraphic modifications caused by multiple denudation events. Through the analysis of denudation amounts across four periods, it was found that the denudation amounts ranged between 0 and 750 m, with an average of approximately 161 m. The Shenzijing-Hashituo sag area experienced the most intense denudation. However, there are potential uncertainties in the denudation restoration process, such as limitations in seismic data resolution. In this study, the latest 3D seismic data with good imaging quality and clear reflection features were collected to minimize errors caused by resolution limitations. Over long timescales, sea-level changes can significantly affect the deposition-denudation balance, leading to cumulative errors.