Controlling factors on the grain size distribution of shallow subsurface coastal sediments at the mouth of Wadi al-Hamd, northeastern Red Sea, Saudi Arabia

الملخص EN

The present study concerned with grain size distribution of shallow subsurface sediments at the mouth of Wadi Al-Hamd, NE Red Sea coast, Saudi Arabia.

The objectives of the study are the description and interpretation of the controlling factors on the spatial and vertical variations in grain size parameters.

Grain size analysis of 206 samples belonging to five shallow cores collected from the tidal flat at the mouth of Wadi Al-Hamd showed that the sediments are generally sandy; with a mean size ranging from fine to medium sand and rarely gravel and mud.

The channel fill sediments showed poor to well sorting, strongly fine skewed and low coefficient of variance except at the base of channel.

The southern lower intertidal flat sediments are heterogeneous moderate to well sorted fine to medium sands, fine to strongly fine skewed and low coefficient of variance.

The beach sediments to the north are well sorted fine to very fine sands, strongly fine skewed and low coefficient of variance.

The size and distribution of sediments are controlled by the texture of the available sediments, hydrodynamics during transportation and depositional.

The available sediments are controlled by the climatically controlled degree and type of weathering at the source, length and power of transporting agent and the gradient of the route.

The study area displays alongshore variation in depositional setting from a low gradient inter-tidal flat to south and wave dominated strand plain system to the north