The detrital and nondetrital elemental compositions of suspended particles in the Tamar Estuary, U.K., have been examined when the estuarine turbidity maximum was well developed and also when high river flow restricted the development of a turbidity maximum. Correlation matrices and 'r'-mode factor analyses were used to identify significant relationships within and between the variances in the fractionated particulate compositions and in the ambient physico-chemical conditions. Marked temporal and spatial differences in the elemental composition of suspended particles were found. At high river flow, suspended particulate compositions throughout the estuary were dominated by dilution and dispersion of an overwhelming flux of riverborne material. Under normal conditions of low riverine particle flux, internal cycling of particles, especially within the turbidity maximum region, controlled the spatial distributions of suspended particle compositions and subsidiary inputs were of greater significance.Key words: estuaries, suspended sediment, particle transport, trace elements