Comparison of basin-scale in situ and meteoric <sup>10</sup>Be erosion and denudation rates in felsic lithologies across an elevation gradient at the George River, northeast Tasmania, Australia
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Published:2022-03-29
Issue:1
Volume:4
Page:153-176
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ISSN:2628-3719
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Container-title:Geochronology
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language:en
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Short-container-title:Geochronology
Author:
VanLandingham Leah A., Portenga Eric W., Lefroy Edward C., Schmidt Amanda H.ORCID, Bierman Paul R.ORCID, Hidy Alan J.
Abstract
Abstract. Long-term erosion rates in Tasmania, at the southern end of Australia's Great Dividing Range, are poorly known; yet, this knowledge is critical for making informed land-use decisions and improving the ecological health of coastal ecosystems. Here, we present quantitative, geologically relevant estimates of erosion rates for the George River basin, in northeast Tasmania, based on in situ-produced 10Be (10Bei) measured from stream sand at two trunk channel sites and seven tributaries (mean: 24.1±1.4 Mgkm-2yr-1; 1σ). These new
10Bei-based erosion rates are strongly related to elevation, which appears to control mean annual precipitation and temperature,
suggesting that elevation-dependent surface processes influence rates of erosion in northeast Tasmania. Erosion rates are not correlated with slope
in contrast to erosion rates along the mainland portions of Australia's Great Dividing Range. We also extracted and measured meteoric 10Be
(10Bem) from grain coatings of sand-sized stream sediment at each site, which we normalize to measured concentrations of reactive 9Be
and use to estimate 10Bem-based denudation rates for the George River. 10Bem/9Bereac denudation rates
replicate 10Bei erosion rates within a factor of 3 but are highly sensitive to the value of 9Be that is found in bedrock
(9Beparent), which was unmeasured in this study. 10Bem/9Bereac denudation rates seem sensitive to recent
mining, forestry, and agricultural land use, all of which resulted in widespread topsoil disturbance. Our findings suggest that
10Bem/9Bereac denudation metrics will be most useful in drainage basins that are geologically homogeneous, where recent
disturbances to topsoil profiles are minimal, and where 9Beparent is well constrained.
Publisher
Copernicus GmbH
Reference148 articles.
1. Adams, B. A. and Ehlers, T.:
Deciphering topographic signals of glaciation and rock uplift in an active orogen: A case study from the Olympic Mountains, USA,
Earth Surf. Proc. Land.,
42, 1680–1692, https://doi.org/10.1002/esp.4120, 2017. 2. Aguilar, G., Carretier, S., Regard, V., Vassallo, R., Riquelme, R., and Martinod, J.:
Grain size-dependent 10Be concentrations in alluvial stream sediment of the Huasco Valley, a semi-arid Andes region,
Quat. Geochronol.,
19, 163–172, https://doi.org/10.1016/j.quageo.2013.01.011, 2014. 3. Aldahan, A., Haiping, Y., and Possnert, G.:
Distribution of beryllium between solution and minerals (biotite and albite) under atmospheric conditions and variable pH,
Chem. Geol.,
156, 209–229, https://doi.org/10.1016/S0009-2541(98)00186-7, 1999. 4. Balco, G., Stone, J. O., Lifton, N. A., and Dunai, T. J.:
A complete and easily accessible means of calculating surface exposure ages or erosion rates from 10Be and 26Al measurements,
Quat. Geochronol.,
3, 174–195, https://doi.org/10.1016/j.quageo.2007.12.001, 2008. 5. Barreto, H. N., Varajão, C. A. C., Braucher, R., Bourlès, D. L., Salgado, A. A. R., and Varajão, A. F. D. C.:
The impact of diamond extraction on natural denudation rates in the Diamantina Plateau (Minas Gerais, Brazil),
J. S. Am. Earth Sci.,
56, 357–364, https://doi.org/10.1016/j.jsames.2014.09.002, 2014.
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