Characterizing sedimentary processes in abandoned channel using compositional data analysis and wavelet transform

Abstract

Grain size distribution (GSD) is essential for characterizing the deposition process. However, it is necessary to consider its compositional constraint to comprehend the statistical distribution of size fractions within the sediments. Compositional data analysis (CoDA) and wavelet transform (WT) represent alternative methods beyond traditional approaches, e.g., probability density function (PDF). This paper introduces a quantitative approach for characterizing Quaternary depositional and environmental changes using abandoned channel infill sediments. The proposed approach integrates CoDA and WT to thoroughly comprehend the depositional patterns observed in abandoned channels and the underlying environmental variability. The depositional model constructed based on CoDA showed coarsening-upward sequences, suggesting a periodic connection between the main channel and the oxbow lake. Three scales of cycles consistent with the depositional model constructed using CoDA were identified based on WT: small, medium, and large-scale cycles of processes. The large-scale cycles indicate the main depositional events, while the medium and small scale reflects the variation within and during deposition. CoDA and WT demonstrate excellent potential in characterizing the GSD and interpreting oxbow lakes' deposition and sedimentation processes.