Evidence of the Importance of Deposition and Winnowing of Surficial Sediments at a Continental Shelf Scale

Abstract

Surficial sediment grain sizes in Bass Strait, southern Australia, vary widely across the Strait. When compared to a calibrated numerical hydrodynamic model of the M₂ tidal circulation, this grain size variation was found to correspond with tidal current intensity. In particular, a correspondence between the sediment entrainment threshold velocity and the maximum tidal current was observed. The results highlight the importance of deposition and winnowing at a continental shelf scale while indicating that current strength is the dominant factor determining the nature of the modern sea bed throughout Bass Strait.