## 4 The Impact of Sequence Structure on Sedimentary Filling  
### Types and Characteristics of Sedimentary Microfacies  
According to the seismic reflection characteristics, six typical seismic phases were identified in the study area (Table 1): the broom-shaped progradation phase, the dome-shaped phase, the chaotic phase, the wedge-shaped divergent phase, the lens-shaped filling phase, and the sheet-like parallel phase. Figure 8: Sequence stratigraphic framework of the Guantao Formation. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Types of Seismic Phase** & **Seismic Reflection** & **Seismic Reflection** & **Seismic Attribute** & **Distribution Location** & **Sedimentary Faces** & **Examples** \\  & **Shape** & **Texture** & **Characteristics** & & **Interpretation** & **Examples** \\ \hline \begin{tabular}{c} broom-shaped \\ progradation phase \\ \end{tabular} & broom-shaped & \begin{tabular}{c} progradation reflection \\ texture \\ \end{tabular} & mid-high amplitude, mid-low continuous & \begin{tabular}{c} uplift periphery, \\ synsedimentary fault \\ downtown plate \\ \end{tabular} & alluvial fan facies & \\ \hline \begin{tabular}{c} dome-shaped phase \\ \end{tabular} & dome-shaped & wave reflection texture & mid amplitude, mid continuous & uplift periphery & alluvial fan facies & \\ \hline \begin{tabular}{c} Chaotic phase \\ \end{tabular} & wedge-shaped & \begin{tabular}{c} chaotic reflection \\ texture \\ \end{tabular} & mid-low amplitude, low continuous & \begin{tabular}{c} synsedimentary fault \\ downtown plate \\ \end{tabular} & alluvial fan facies & \\ \hline \begin{tabular}{c} wedge-shaped \\ divergent phase \\ \end{tabular} & wedge-shaped & \begin{tabular}{c} divergent reflection \\ texture \\ \end{tabular} & mid amplitude, mid continuous & sag peripheral slope & \begin{tabular}{c} alluvial fan-fluvial \\ faces \\ \end{tabular} & \\ \hline \begin{tabular}{c} lens-shaped filling \\ phase \\ \end{tabular} & \begin{tabular}{c} lens-shaped \\ \end{tabular} & filling reflection texture & \begin{tabular}{c} mid-low amplitude, \\ mid-low continuous \\ \end{tabular} & gentle area in the sag & fluvial facies & \\ \hline \
\begin{tabular}{c} sheet-like parallel phase \\ \end{tabular} & sheet-like &
\begin{tabular}{c} parallel-subparallel \\ reflection texture \\ \end{tabular} & mid-high amplitude, mid-highcontinuous & gentle area in the sag & fluvial facies & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Characteristics of six typical seismic phases. The broom-shaped degradation phase mainly presented a reflection texture of degradation, reflecting the sedimentary process of continuously extending forward. The seismic in-phase axes in this phase were mostly characterized by medium-strong amplitude and medium-low continuity. This phase was mainly distributed in the steep slope zone and the down-dip of syn-sedimentary faults in the area, reflecting the alluvial fan facies (Table 1A). The dome-shaped phase generally presented a \"convex top and flat bottom\" dome-shaped reflection, with poor layering and characteristics of medium amplitude and medium continuity. This phase was mainly distributed in steep slope zones. Multiple dome-shaped phases were horizontally stacked, reflecting the transverse cross section of alluvial fans (Table 1B). The chaotic phase generally exhibited irregular chaotic reflections, with low to medium amplitude levels and low-continuity seismic in-phase axes characteristics. This phase was mainly distributed in the descending plate of syn-sedimentary faults close to faults, which can reflect the rapid sedimentation of alluvial fans (Table 1C). The seismic reflection of the wedge-shaped divergent phase showed a pattern of gradually decreasing amplitude and continuity towards a certain direction along the same axis. This phase was mainly distributed in depression slopes, reflecting the edge of alluvial fans or the fluvial facies (Table 1D). The lens-shaped filling phase was generally lens-shaped, with medium to low amplitude and continuity.