Morphodynamics and sedimentology of the Malindi-fundisa coastal area associated with the heavy mineral deposition

Abstract

The short-term morphodynamic states of the Malindi-Fundisa coasts varying in morphological, tidal, grain size and mineralogical characteristics have been examined as a basis for describing the different environments of sediment deposition taking place at present. Further examination of coastal geomorphology, sediment characteristics and process elements has shown that the Fundisa coast is transgressional; Mambrui-Sabaki is depositionally emergent and the Silversands Beach is erosional. In addition the coast is further characterized by the degree of protection, namely those areas bordered by fringing reefs subrecent beach barriers are protected and the rest are exposed. A casual study of fluctuation in density or abundance of certain organisms dwelling within the shallow marine ecosystem makes it possible to determine the cross effect of fauna-floral contribution and morphodynamic distribution. The organism- sediment relationship become more evident when the morphodynamic state of the beach and nearshore environment is taken into consideration. The present investigation also provides information on the localities of heavy mineral deposition along the Malindi-Fundisa coast. Geochemical and petrographical parameters of surface sediments have been examined to delineate the heavy mineral-rich (consisting essentially of ilmenite, haematite, magnetite, zircon and rutile) regions. The results demonstrate a well defined correlation between the heavy mineral concentrations and the corresponding morphodynamic processes.