## 3 Data and Methods
### Methods  
Seismic sedimentology, a concept developed after sequence stratigraphy, is employed to study sedimentary rocks and depositional processes using seismic data [24; 25]. Seismic sedimentology incorporates two complementary aspects: model-driven seismic geomorphology and data-driven seismic lithology [26]. An integrated seismic sedimentological workflow was developed by integrating geophysical, geochemical (elements and isotopes), and geological data to reconstruct evaporite facies in the Taidong area (Figure 3). The S-wave 3D seismic dataset was first phase-rotated to \(-90^{\circ}\) to make the seismic event corresponding to stratum. Wireline logs, including DTS and DEN, were then used to tie the phase-rotated seismic data. After achieving a good well-seismic tie, boundaries of the standard zones were interpreted. These boundaries define an isochronous framework, providing a connection between the two-way travel time in the seismic data and the depth and geological age indicated by the standard zones (Figures 1 and 3). This connection is essential for analyzing the relationship between sedimentary facies and regional climate change.  
Figure 2: A S-wave 3D seismic profile (1.130) crossing Well SE9 in Taideng area, Sanhu Depression, Giddam Basin (see the location of profile A-B in Figure 1).  
Average frequency and interval velocity of the studied K2 to K0\({}^{\prime}\) is 25 Hz and 600 m/s, respectively. Then the S-wave seismic data with predominant frequency of 25 Hz have a vertical resolution of 6 m according to a quarter of \(\lambda\)[27]. Considering the seismic frequency bandwidth and stratum thickness in Taidong area, the low and high frequency is determined to be 7 Hz (21 m resolution) and 35 Hz (4 m resolution). The phase-rotated seismic data were decomposed into three sub-cubes using a wavelet algorithm: low-frequency (7 Hz), moderate-frequency (25 Hz), and high-frequency (35 Hz) components. These sub-cubes were then fused using the RGB method, where red, green, and blue represent low, moderate, and high frequencies, respectively. In this scheme, low frequencies correspond to thicker strata, moderate frequencies indicate intermediate thickness, and high frequencies reflect thinner layers ([PERSON] et al., 2024). The independent nature of the three primary colors in the RGB fusion allows for the expression of geological features at different scales simultaneous [28,29]. Stratal slices were generated from the RGB-fused cube and subsequently interpreted according to the geomorphology features and information derived from geochemical and geological data.  
The geochemical data, i.e., element and isotopes derived from regional (boreholes SG-1, SG-1b, and SG-5) and global (temperature anomaly in the Equatorial West Pacific and precipitation anomaly in China and East Asian) parameters, reflect variables such as precipitation, temperature, and water salinity. Geological data, including modern Lake Chad's evaporite environment and published saline pan models, were used for further interpretation. Stratal slices were generated every two milliseconds, corresponding to the sampling rate of the S-wave seismic data, starting from the bottom of K2 (1.5 Ma BP) upwards. The slices reveal clear lateral geomorphology features with different scales, which is the key to interpret evaporite facies in Taidong area. Three representative slices (Slice 1, 2, and 3) from the K2, K1, and K0 standard zones, where aridity and water salinity are different (Figure 2) were selected to investigate seismic facies by seismic geomorphology and seismic lithology. These seismic facies were then transformed into sedimentary facies  
Figure 3: Data and workflow used in this paper.  
by integrating geochemical and geological information in Qaidam Basin and modern analogs in Lake Chad. Time-structural maps of the three slices assisted in interpreting the sedimentary environments in Taidong area.