10Be-derived denudation rates from the Burdekin catchment: The largest contributor of sediment to the Great Barrier Reef

Croke, Jacky, Bartley, Rebecca, Chappell, John, Austin, Jenet M., Fifield, Keith, Tims, Stephen G., Thompson, Chris J. and Furuichi, Takahisa (2015) 10Be-derived denudation rates from the Burdekin catchment: The largest contributor of sediment to the Great Barrier Reef. Geomorphology, 241 122-134. doi:10.1016/j.geomorph.2015.04.003


Author Croke, Jacky
Bartley, Rebecca
Chappell, John
Austin, Jenet M.
Fifield, Keith
Tims, Stephen G.
Thompson, Chris J.
Furuichi, Takahisa
Title 10Be-derived denudation rates from the Burdekin catchment: The largest contributor of sediment to the Great Barrier Reef
Formatted title
10Be-derived denudation rates from the Burdekin catchment: The largest contributor of sediment to the Great Barrier Reef
Journal name Geomorphology   Check publisher's open access policy
ISSN 0169-555X
1872-695X
Publication date 2015-07-05
Sub-type Article (original research)
DOI 10.1016/j.geomorph.2015.04.003
Open Access Status Not yet assessed
Volume 241
Start page 122
End page 134
Total pages 13
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Language eng
Subject 1904 Earth-Surface Processes
Abstract Terrestrial cosmogenic nuclides (TCNs) such as Beryllium-10 (10Be) are now routinely used to reconstruct erosional rates over tens of thousands of years at increasingly large basin scales (>100,000km2). In Australia, however, the approach and its assumptions have not been systematically tested within a single, large drainage basin. This study measures 10Be concentrations in river sediments from the Burdekin catchment, one of Australia's largest coastal catchments, to determine long-term (>10,000years), time-integrated rates of sediment generation and denudation. A nested-sampling design was used to test for effects of increasing catchment scale on nuclide concentrations with upstream catchment areas ranging from 4 to 130,000km2. Beryllium-10 concentrations in sediment samples collected from the upstream headwater tributaries and mid-stream locations range from 1.8 to 2.89×105atomsg-1 and data confirm that nuclide concentrations are well and rapidly mixed downstream. Sediment from the same tributaries consistently yielded 10Be concentrations in the range of their upstream samples. Overall, no decrease in 10Be concentrations can be observed at the range of catchment scales measured here. The mean denudation rate for all river sediment samples throughout the Fanning subcatchment (1100km2) is 18.47mMa-1, which compares with the estimate at the end of the Burdekin catchment (130,000km2) of 16.22mMa-1. Nuclide concentrations in the lower gradient western and southern catchments show a higher degree of variability, and several complications emerged as a result of the contrasting geomorphic processes and settings. This study confirms the ability of TCNs to determine long-term denudation rates in Australia and highlights some important considerations in the model assumptions that may affect the accuracy of limited sampling in large, low-gradient catchments with long storage times.
Formatted abstract
Terrestrial cosmogenic nuclides (TCNs) such as Beryllium-10 (10Be) are now routinely used to reconstruct erosional rates over tens of thousands of years at increasingly large basin scales (> 100,000 km2). In Australia, however, the approach and its assumptions have not been systematically tested within a single, large drainage basin. This study measures 10Be concentrations in river sediments from the Burdekin catchment, one of Australia's largest coastal catchments, to determine long-term (> 10,000 years), time-integrated rates of sediment generation and denudation. A nested-sampling design was used to test for effects of increasing catchment scale on nuclide concentrations with upstream catchment areas ranging from 4 to 130,000 km2. Beryllium-10 concentrations in sediment samples collected from the upstream headwater tributaries and mid-stream locations range from 1.8 to 2.89 × 105 atoms g−1 and data confirm that nuclide concentrations are well and rapidly mixed downstream. Sediment from the same tributaries consistently yielded 10Be concentrations in the range of their upstream samples. Overall, no decrease in 10Be concentrations can be observed at the range of catchment scales measured here. The mean denudation rate for all river sediment samples throughout the Fanning subcatchment (1100 km2) is 18.47 m Ma−1, which compares with the estimate at the end of the Burdekin catchment (130,000 km2) of 16.22 m Ma−1. Nuclide concentrations in the lower gradient western and southern catchments show a higher degree of variability, and several complications emerged as a result of the contrasting geomorphic processes and settings. This study confirms the ability of TCNs to determine long-term denudation rates in Australia and highlights some important considerations in the model assumptions that may affect the accuracy of limited sampling in large, low-gradient catchments with long storage times.
Keyword Burdekin catchment
Geological erosion rates
Subtropical
Terrestrial cosmogenic nuclides
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Geography, Planning and Environmental Management Publications
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