Coastal sedimentary systems are dynamic environments where morphological changes, sediment transport, and geochemical processes interact to shape coastal landscapes. This study presents a comprehensive investigation of morphosedimentary dynamics across four coastal sites in Guyana (Wellington Park, Mahaica, Abary and Mahaicony) through integrated analysis of over 100 sediment samples. The objectives of this study are to: characterise sediment properties across the four coastal sites; identify site-specific and depth-dependent patterns; determine relationships between sediment properties and depositional environments; assess contamination status and geochemical signatures; and interpret morphosedimentary dynamics in the context of coastal processes and environmental conditions. Multi-proxy data, including moisture content, 27 trace elements, grain size distributions, and loss on ignition were analysed using descriptive statistics, comparative analyses, correlation studies, and multivariate statistical techniques (Principal Component Analysis, hierarchical clustering, and K-means clustering). Results reveal three distinct sediment facies with contrasting depositional characteristics: (1) Abary and Mahaicony represent low-energy estuarine/tidal flat environments dominated by fine-grained sediments (82% mud/silt), while (2) Mahaica represents a higher-energy nearshore/beach environment with coarser sediments (37.5% fine sand). Moisture content decreases significantly with depth (1.16% at 0–10 cm to 0.93% at 21–30 cm), indicating compaction and diagenetic processes. Strong inter-element correlations (Cu–Zn-Pb: r > 0.88; V-Ni: r = 0.85) indicate common geochemical sources. Redox analysis reveals strongly reducing conditions at Mahaicony (Fe/Mn ratio ~ 150) compared to more oxidising conditions at other sites. Contamination assessment using Pollution Load Index (PLI = 0.91) and Geoaccumulation Index (Igeo < 0 for all metals) indicates uncontaminated sediments with natural geochemical signatures. These findings provide critical baseline data for understanding coastal morphodynamics, sediment transport pathways, and environmental conditions essential for coastal management and hazard assessment in this dynamic tropical coastal system.
Temitope D. Timothy Oyedotun (Wed,) studied this question.