Texture variability of clastic marine sediments across three major Harbours along the Egyptian Red Sea coast

Abstract

Sediment textural variability and distributions of one hundred sediments samples across three major strategic Harbours, Quseir, Safaga, and Hurghada, along the Northern Red Sea have been assessed. Grain size parameters and cluster analysis have been applied to reveal indices of the marine environment, mainly the energy and hydrodynamic conditions, which controlled the mode of transportation and depositional settings. The three Harbours exhibited shallow marine environment, corresponding to siliclastic terrigenous flux, associated with carbonate sediments, which sustained biogenic fragments nearby reef and mangrove sites. Depositional settings were controlled by bottom topography, sediments sources, water depth, and closeness from shoreline. This was also coupled with the exposure degree to anthropogenic discharges that triggered sediment texture disturbance and impacted seabed habitat of Safaga Harbour. The latter is more affected by contamination than Quseir and Hurghada Harbours as its topography favored the accumulation of contaminants and acted as pollutant-traps. The C-M pattern suggested rolling as the main mode of nearshore sediments transportations across the three Harbours. Suspension transportation was recognized in Quseir Harbour with higher ratio compared with Safaga Harbour, while it was absent in Hurghada Harbour. Nevertheless, the investigated Harbours shared some common features, particularly low-energy hydrodynamic regime corresponding to their semi-isolated locations and arid climatic conditions, which ruled sediments texture and distributions.