On the possibility of high-velocity tidal streams as dynamic barriers to longshore sediment transport: evidence from the continental shelf off the Gulf of Kutch, India

Abstract

Differences in the bathymetry, bottom topography and the abundance of mica and clay minerals on the continental shelf north and south of the Gulf of Kutch, a macrotidal bay, indicate the presence of two distinct sedimentary environments. The northern part is characterised by accumulation of sediments (prograding sediments of the Indus delta) and higher concentrations of mica and clay minerals, whereas the southern part is deprived of sediments and has relatively lower concentrations of mica and clay minerals. The distinct differences have resulted because the high-velocity (2 to 2.5 knots) tidal stream at the gulf mouth acts as a dynamic barrier inhibiting sediment transport across the mouth. Differences in the distribution of sand-size and clay-size sediments further indicates that it acts as a selective filter that is more effective against the coarser end of the size spectrum.