Chronology of Murrumbidgee River palaeochannels on the Riverine Plain, southeastern Australia

Abstract

Four major periods of palaeochannel activity have been identified on the Murrumbidgee sector of the Riverine Plain of southeastern Australia. On the basis of stratigraphic information the channels reveal a picture of changing flow conditions during the last full glacial cycle. The ages of the periods were determined from nearly 40 thermoluminescence dates on surficial fluvial and aeolian sediments. These are named the Coleambally phase, which occurred from 105 to 80 ka (the mid‐ to latter part of Oxygen Isotope Stage 5), the Kerarbury phase from 55 to 35 ka (Stage 3), the Gum Creek phase from 35 to 25 ka (late Stage 3 to early Stage 2) and the Yanco phase from 20 to 13 ka (late Stage 2). The present flow regime was established by about 12 ka (Stage 1). The first two phases correlate with episodes of enhanced fluvial activity in northern and central Australia and with reduced dust activity globally. The phases in Stage 2 appear to be associated with seasonal snow melt and increased peak flows in periods flanking the Last Glacial Maximum. Source‐bordering aeolian dunes associated with the Coleambally, Kerarbury and Yanco phases were found, however, the TL dates show that some have undergone aeolian reworking. Thermoluminescence dating and fluvial stratigraphy have revealed a detailed picture of Late Quaternary climate and flow regime changes that has the potential to extend to identified deposits stratigraphically older than those described here.

A model for the active origin and development of source-bordering dunefields on a semiarid fluvial plain: A case study from the Xiliaohe Plain, Northeast China

“…Twidale, 1972;Bowler, 1978;Zhu et al, 1981Zhu et al, , 1987Carver and Brook, 1989;Markewich and Markewich, 1994;Williams, 1994;Nanson et al, 1995;Page et al, 1996Page et al, , 2001, they do not fully correspond to the dunefields in our study. It is commonly considered that they develop mainly due to the fact that sand on channel beds is deflated and deposited adjacent to the channel downwind.…”

Chronology of Late Pleistocene environmental changes in the lower Mahi basin, western India

“…Globally, the soil episode S m in the Chinese loess (see for, e.g., Chen et al, 1997) indicates a more humid phase. Evidence of enhanced fluvial activity in southeastern Australia is seen between 53 ka and 35 ka and 105 and 80 ka (Page et al, 1996), and during similar periods in central Australia (Nanson et al, 1992). Comparable regionally synchronous episodes of fluvial activity based on evidence from a Gilbert delta fan in northern Australia have been reported at around 50-40 ka by Nanson et al (1991).…”

Alluvial sedimentation rates from southeastern Australia indicate post-European settlement landscape recovery

“…The persistence of these residual landforms is arguably a response to the general decline in fluvial activity that has occurred across southeastern Australia over timescales ranging from the last two glacial cycles Page et al, 1996;Nott et al, 2002) to the period since the middle Holocene (Dodson, 1986;Nanson et al, 1995;Kemp, 2001;Rustomji et al, 2006b). The likelihood of an alluvial deposit formed under a prior climatic regime remaining intact over subsequent millennia appears to be greater than the probability of it being eroded and/or replaced during a later, weaker hydrologic phase.…”