Longitudinal correlation of Late Quaternary terrace sequences of Widden Brook, Southeastern Australia

Abstract

Terrace remnants on Widden Brook, southeastern Australia, were examined and correlated longitudinally to establish their evolutionary history. Three discontinuous terrace sequences, the Baramul, Widden and Kewarra, were identified in a 26 km reach using sedimentology, topography and chronology. Each terrace sequence occurred within a geomorphically distinct valley setting: an upstream constriction, a valley expansion and a highly constricted downstream section. Radiocarbon and optically stimulated luminescence ages indicated that each terrace sequence was formed during the Late Pleistocene and Holocene (16.7-0.5 ka cal BP). However, their sedimentology and topography were shown to differ significantly. We present evidence that both climate and the exceedance of intrinsic geomorphic thresholds were major contributing factors responsible for the formation of these terrace sequences.