Climatically-Controlled River Terraces in Eastern Australia

Dados Bibliográficos

ID15801844
AutoresJames Daley (0000-0003-4271-5664, Griffith University, autor correspondente), Tim J Cohen (0000-0003-4081-9523, University of Wollongong), Tim Cohen (University of Wollongong)
Ano2018
Volume1
Fascículo3
Páginas23-23
Data de publicação2018-10-16
Peer ReviewedSim
Open AccessSim
TipoARTICLE
PeriódicoQuaternary (JOURNAL)
Identificadores do periódicoISSN: 2571-550X • E-ISSN: 2571-550X
EditoraMultidisciplinary Digital Publishing Institute (PUBLISHER • CH)
DOI10.3390/quat1030023
OpenAlexW2896690467
IdiomaEN
Citações recebidas2
Referências citadas99

In the tectonically stable rivers of eastern Australia, changes in response to sediment supply and flow regime are likely driven by both regional climatic (allogenic) factors and intrinsic (autogenic) geomorphic controls. Contentious debate has ensued as to which is the dominant factor in the evolution of valley floors and the formation of late Quaternary terraces preserved along many coastal streams. Preliminary chronostratigraphic data from river terraces along four streams in subtropical Southeast Queensland (SEQ), Australia, indicate regionally synchronous terrace abandonment between 7.5–10.8 ka. All optically stimulated luminescence ages are within 1σ error and yield a mean age of incision at 9.24 ± 0.93 ka. Limited samples of the upper parts of the inset floodplains from three of the four streams yield near-surface ages of 600–500 years. Terrace sediments consist of vertically accreted fine sandy silts to cohesive clays, while top stratum of the floodplains are comprised of clay loams to fine-medium sands. The inundation frequency of these alluvial surfaces depends on their specific valley setting. In narrow valley settings, where floodplains comprise 20%), the terraces are no longer inundated. Floodplain inundation frequencies also vary between these settings by an order of magnitude between 5- to 50-year AEP, respectively. The correlation of terrace abandonment within SEQ with fluvial and palaeoenvironmental records elsewhere in the subtropics, and more broadly across eastern Australia, are an indication that terrace abandonment has primarily been driven by climatic forcing. Contemporaneous channel incision in the early Holocene may have been driven by an increasingly warmer and wetter environment in SEQ, with a climate commensurate with the delivery of more extreme weather events. Following channel incision, many streams in SEQ have been largely confined to their entrenched “macrochannel” form that remains preserved within the valley floor

Aggradation · Alluvium · Archaeology · Floodplain · Fluvial · Geography · Geomorphology · Hydrology (agriculture · Physical geography · Ravine · River terraces · Sediment · STREAMS · Structural basin · Terrace (agriculture · Geological formations and processes · Geology and Paleoclimatology Research · Hydrology and Sediment Transport Processes · Geology