<p>Mixture processes between siliciclastic and bioclastic grains play a key role in shaping sedimentary environments and controlling morphodynamics in tropical coastal zones worldwide. A morphosedimentary study, based on sediment cores and remote sensing, was conducted on the Ilha do Amor Barrier along Brazil’s Semi-Arid Coast. Six sedimentary facies were identified, associated with beach, dune and tidal flat environments. These facies exhibit clear compositional and granulometric segregation. This is particularly evident in the development of mixed siliciclastic-carbonate beaches and aeolian environments dominated by siliciclastic sediments, though with notable bioclastic enrichment (~ 20%) in the finer fractions. This sedimentological distribution occurs within a setting characterized by morphosedimentary inversion, with retrogradation processes in the eastern portion and accretionary dynamics in the western sector, including the opening and closing of tidal inlets. The landward displacement of the coastline is evidenced by the succession of coarse siliciclastic facies, associated with a steep reflective beach, and finer bioclastic facies, associated with a flat terrace. This coastal evolution corresponds to a reflective plus low-tide terrace beach state. In this context, hydrodynamic sorting promotes intense mixing between bioclastic and siliciclastic grains, while aeolian processes favor siliciclastic enrichment and the landward transport of finer bioclastic material. These dynamics are fundamental to explaining the presence of eolianites in the mid-barrier zone. Therefore, the development of a siliciclastic to mixed siliciclastic-carbonate coastal barrier reflects the influence of local environmental factors, including a semi-arid climate with low terrigenous input, active carbonate production in shallow waters, and a mesotidal regime with pronounced seasonality in wave climate and wind intensity.</p>