Grain‐size characteristics of fine‐grained unflocculated sediments II:‘multi‐round’ distributions

The grain‐size spectrum of sediment deposited by settling of a suspension with a ‘one‐round’ grain size distribution is described by a power law in which the integer exponent characterizing the fine‐grained limb is increased by one over that of the suspension. If this better‐sorted sediment, in turn, is resuspended and settles, further sorting and steepening of the limb occurs. Each resuspension event or‘round’changes the distribution by a predictable amount. Equations describing this sorting process, based on the derivation of the one‐round equation, are fitted to grain‐size analyses of well‐sorted sediment from a variety of locations to verify the model. A suite of sandy bottom sediment samples from the Bay of Fundy shows that the steepness of the fine‐grained limbs of the sand fraction indeed increases in integral steps.