气候变化领域集成服务门户(CCPortal): Controls on denudation along the East Australian continental margin

CCPortal

DOI	10.1016/j.earscirev.2021.103543
	Controls on denudation along the East Australian continental margin
	Codilean A.T.; Fülöp R.-H.; Munack H.; Wilcken K.M.; Cohen T.J.; Rood D.H.; Fink D.; Bartley R.; Croke J.; Fifield L.K.
发表日期	2021
ISSN	00128252
卷号	214
英文摘要	We report a comprehensive inventory of 10Be-based basin-wide denudation rates (n = 160) and 26Al/10Be ratios (n = 67) from 48 drainage basins along a 3000 km stretch of the East Australian passive continental margin. We provide data from both basins draining east of the continental divide (n = 37) and discharging into the Tasman and Coral Seas, and from basins draining to the west as part of the larger Murray-Darling and Lake Eyre river systems (n = 11). 10Be-derived denudation rates in mainstem samples from east-draining basins range between 7.7 ± 1.9 (± 1σ; Mary) and 54.6 ± 13.7 mm kyr−1 (North Johnstone). Denudation rates in tributary samples range between 3.0 ± 0.7 (Burdekin) and 70.2 ± 18.9 mm kyr−1 (Liverpool). For west-draining basins, denudation rates are overall lower and with a more restricted range of 4.8 ± 1.2 (Barcoo) to 15.4 ± 3.6 mm kyr−1 (Maranoa) in mainstem samples, and between 4.4 ± 1.0 (Murrumbidgee) and 38.5 ± 7.8 mm kyr−1 (Murray) in tributary samples. East Australian denudation rates (median = 14.5 mm kyr−1) are similar to those found in other postorogenic landscapes (global median = 12.4 mm kyr−1) and the medians of the top 10% denudation rates recorded here (46.5 mm kyr−1) and in other passive margin settings are also similar, despite differences in topography and precipitation. These median denudation rate values are close to the 95th percentile denudation rate for all tectonically passive basins (≈53 mm kyr−1) and are very similar to the global silicate weathering speed limit (≈58 mm kyr−1) calculated as the 95th percentile of global soil weathering rates. The above suggests that in post-orogenic terrain, the overall rates of topographic decay have a ‘speed limit’ that is imposed by the rate at which rock is converted to soil by chemical weathering. Denudation rates along the East Australian margin correlate with topographic metrics at both the mainstem basin scale and at the smaller tributary basin scale suggesting that topography exerts the main control on rates of landscape lowering in this setting. An important link between denudation rate and rainfall is also inferred: the highest mainstem 10Be denudation rates all occur in basins which also have the highest rainfall amounts and there is a strong correlation between the distance knickpoints have travelled upstream from the river mouth and basin area — a proxy for discharge and so to some extent also rainfall. On both sides of the divide, in all but a few of the samples, 26Al/10Be ratios are consistently lower than what is expected in a setting where sediments experience a simple and continuous exposure history. East of the continental divide, the lowest 26Al/10Be ratios are found in basins that also experience increased flood variability. We posit that there is a causal link between the hydrological variability that characterises the coastal rivers of eastern Australia and the observed non-steady state 26Al/10Be ratios: the periodic stripping of vertically accreted floodplains by large floods means that deeper and potentially older material is periodically incorporated into the sediment mix transported by the modern river. © 2021 Elsevier B.V.
关键词	Australia Cosmogenic 10Be Cosmogenic 26Al/10Be Denudation Great Dividing Range Passive continental margin
语种	英语
来源期刊	Earth Science Reviews
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203992
作者单位	School or Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW 2522, Australia; ARC Centre of Excellence for Australian Biodiversity and Heritage (CABAH), University of Wollongong, Wollongong, NSW 2522, Australia; Australia's Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia; Department of Earth Science and Engineering, Imperial College London, London, SW7 2AZ, United Kingdom; CSIRO Land and Water, GPO Box 2583, Brisbane, QLD 4001, Australia; School of Geography, University College Dublin, Dublin 4, Ireland; Research School of Physics, The Australian National UniversityACT 2601, Australia
推荐引用方式 GB/T 7714	Codilean A.T.,Fülöp R.-H.,Munack H.,et al. Controls on denudation along the East Australian continental margin[J],2021,214.
APA	Codilean A.T..,Fülöp R.-H..,Munack H..,Wilcken K.M..,Cohen T.J..,...&Fifield L.K..(2021).Controls on denudation along the East Australian continental margin.Earth Science Reviews,214.
MLA	Codilean A.T.,et al."Controls on denudation along the East Australian continental margin".Earth Science Reviews 214(2021).