Geomorphology and Internal Architecture of the Ancestral Burdekin River Across the Great Barrier Reef Shelf, North-East Australia

  1. Michael D. Blum5,
  2. Susan B. Marriott6 and
  3. Suzanne F. Leclair7
  1. C. R. Fielding1,2,
  2. J. D. Trueman1,
  3. G. R. Dickens3,4 and
  4. M. Page3

Published Online: 17 MAR 2009

DOI: 10.1002/9781444304350.ch18

Fluvial Sedimentology VII

Fluvial Sedimentology VII

How to Cite

Fielding, C. R., Trueman, J. D., Dickens, G. R. and Page, M. (2009) Geomorphology and Internal Architecture of the Ancestral Burdekin River Across the Great Barrier Reef Shelf, North-East Australia, in Fluvial Sedimentology VII (eds M. D. Blum, S. B. Marriott and S. F. Leclair), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304350.ch18

Editor Information

  1. 5

    Baton Rouge, Louisiana, USA

  2. 6

    School of Geography and Environmental Management, University of the West of England, Bristol BS16 1QY, UK

  3. 7

    Department of Earth and Environmental Sciences, Tulane University, Dimwiddie Hall, New Orleans, LA 70118, USA

Author Information

  1. 1

    Department of Earth Sciences, University of Queensland, Qld 4072, Australia

  2. 2

    Department of Geosciences, 214 Bessey Hall, University of Nebraska-Lincoln, NE 68588-0340, USA

  3. 3

    School of Earth Sciences, James Cook University, Townsville, Qld 4811, Australia

  4. 4

    Department of Earth Sciences, Rice University, Houston, TX 77005, USA

Publication History

  1. Published Online: 17 MAR 2009
  2. Published Print: 15 FEB 2005

Book Series:

  1. Special Publication Number 35 of the International Association of Sedimentologists

Book Series Editors:

  1. Ian Jarvis

Series Editor Information

  1. School of Earth Sciences and Geography, Centre for Earth and Environmental Science Research, Kingston University, Penrhyn Road, Kingston-upon-Thames KT1 2EE, UK

ISBN Information

Print ISBN: 9781405126519

Online ISBN: 9781444304350

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Keywords:

  • geomorphology and internal architecture of ancestral Burdekin River;
  • ancestral channel of Burdekin River - traced across the Great Barrier Reef;
  • palaeo-Burdekin channel;
  • cross-shelf channel profile;
  • channel form and fill;
  • channel planform and course;
  • channel floor profile - to provide more or less faithful record of original channel gradient

Summary

The ancestral channel of the Burdekin River has been traced across the Great Barrier Reef continental shelf of north-east Australia via a dedicated, high-resolution seismic reflection survey, and is continuous from the modern coastline to within c. 10 km of the shelf edge. The channel, entrenched into a relatively flat surface of interpreted compact Pleistocene alluvium and buried beneath up to a few metres of late Holocene marine sediment, is believed to record late Pleistocene drainage through the last glacial cycle. A plot of channel floor elevation against distance outboard from the coastline shows that the long profile of the palaeochannel is stepped, and can be divided into 14 segments alternating between gentle gradient (flats) and steeper gradient (ramps). The segments clearly delineate zones of similar channel width and depth, cross-sectional geometry, and sinuosity as interpreted from a constructed plan of the channel course. Channels in many segments are characterized by evidence for limited, systematic lateral accretion. The upper parts of channel fills have a concentric geometry and high-amplitude reflection character, suggesting final infilling during a different regime to that responsible for channel excavation and initial filling. The stepped profile is interpreted to be a consequence predominantly of falling sea level associated with the last glacial cycle. Channels were cut and partially filled during the fall and lowstand, and then backfilled during the Holocene sea level rise. The stepped long profile, the simple nature of channel cross-sections and the shallow entrenchment of the channel (as opposed to valley incision) indicate that the Burdekin was unable to reach equilibrium with environmental conditions during sea-level drawdown, but rather was constantly adjusting to repeated changes in base level and other variables. The contrasting character of the Burdekin palaeochannel relative to palaeochannels of similar age on other continental margins (many of which occupy pronounced incised valleys) can be attributed to the limited sediment supply and runoff to this margin, the physiography of the Great Barrier Reef, and the compact nature of the Pleistocene land surface into which the channel was entrenched.