Concentración y composición mineralógica de la materia en suspensión en las aguas de la Bahía de Cádiz y plataforma continental adyacente

Resumen

The study of the concentration and mineralogical composition of suspended matter in Cadiz bay and adjacent continental shelf has been made to determine transport paths and behaviour of clay minerals. The higher concentrations of suspended matter are found in the outer bay, specially in the oriental sector. Low concentrations appear in the internal zones of the bay and inner continental shelf, less affected by tidal currents and with a low continental supply respectively. The most abundant clay minerals in suspended sediments are illite followed by smectite, clorite, kaolinite and randomly mixed-layered illite-smectite. The relations between the clay minerals were established by Q-mode Factor Analysis. The main clay minerals association obtained in suspended matter is l>S>CI>l-S>K. The clay minerals distribution indicates high concentration of illite in the inner and protected part of Cadiz bay, while in the adjacent marine zones predominates smectite. Those diferences can be explained considering processes such as settling and diferential transport of clay minerals in marine domain, in relation with hydrodynamics factors, and the ubication of main sources of sediment supply that control the mineralogical composition and concentration of suspended matter.