Interaction between continental and marine end-members gives rise to the natural biogeochemical processes in Sharm Al-Kharrar, a lagoon in the arid Red Sea region. Twenty-nine surface sediment samples were collected from the area and their mud fraction analysed for grain size, OC, CaCO3, mineralogy and elemental composition. The mud fraction consisted of a mixture of siliciclastic/calcareous materials, dominated by silt size materials and characterised by low OC (average 0.71% š0.13); CaCO3 varied widely, with an average of 45% š18. Concentrations of Al, Fe, Mn, Cu, Ni, Cr, V and Ba showed a wide range of variation throughout the Sharm. The results were normalised to Al and subjected to cluster analysis in order to examine the relations between the mineralogy and the elemental composition. The contents of Al, Fe, Mn, Cu, Ni, Cr, V and Ba appeared to be influenced by the mixing of the two end-members in addition to the physiochemical processes associated with the mixing between episodic freshwater flooding and seawater. Zn was the single element that showed a slight departure from the mixing model.