Imperial College London
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DrDylanRood

Faculty of Engineering, Department of Earth Science & Engineering

Senior Lecturer
 
 
 
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Contact

 

+44 (0)20 7594 7461d.rood

 
 
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Location

 

4.43Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Neilson:2017:10.1016/j.chemgeo.2017.09.024,
author = {Neilson, TB and Schmidt, AH and Bierman, PR and Rood, DH and Gonzalez, VS},
doi = {10.1016/j.chemgeo.2017.09.024},
journal = {Chemical Geology},
pages = {119--130},
title = {Efficacy of in situ and meteoric ¹Be mixing in fluvial sediment collected from small catchments in China},
url = {http://dx.doi.org/10.1016/j.chemgeo.2017.09.024},
volume = {471},
year = {2017}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Using measurements of in situ and meteoric 10Be in fluvial sand to measure erosion rates, quantify soil loss, and trace sediment sources and sinks relies on the assumption that such sediment is well-mixed and representative of the upstream area. We test this assumption at 13 river junctions in three tributary watersheds (200–2500 km2) to the Mekong River, Yunnan, China, where human alteration of the landscape is significant and widespread.We find that two of the three watersheds mix well for in situ 10Be and none mix well for meteoric 10Be when considering the concentration of 10Be at the outlet compared to the area-weighted mean of headwater samples. We also assessed mixing at 13 river junctions by comparing the erosion rate-weighted isotopic concentration of sediment taken from tributaries upstream of a junction to the concentration in a sample taken downstream of the junction. With this metric, mixing is generally poor for both in situ and meteoric 10Be but is better for in situ 10Be than for meteoric 10Be (p < 0.05). This is likely because in situ 10Be is measured in quartz, which is resilient to physical and chemical breakdown in river systems whereas meteoric 10Be is measured in grain coatings which can abrade and dissolve.Basins eroding faster (> 100 mm/kyr) tend to mix better than slowly eroding basins. We find no evidence that agricultural land use in sampled basins affects sediment mixing downstream. Mixing improves with increased basin area (particularly > 200 km2), increased sampling distance downstream from an upstream junction (> 500 m), and increased difference in size between tributaries (one tributary > 3 times larger than the other). The most important factor affecting mixing efficacy for both in situ and meteoric 10Be is the fraction of the basin area contributing to the downstream sample that does not contribute to the upstream samples. Junctions with > 2% of the basin area unsampled by upstream samples tend not to mix as
AU  - Neilson,TB
AU  - Schmidt,AH
AU  - Bierman,PR
AU  - Rood,DH
AU  - Gonzalez,VS
DO  - 10.1016/j.chemgeo.2017.09.024
EP  - 130
PY  - 2017///
SN  - 0009-2541
SP  - 119
TI  - Efficacy of in situ and meteoric ¹Be mixing in fluvial sediment collected from small catchments in China
T2  - Chemical Geology
UR  - http://dx.doi.org/10.1016/j.chemgeo.2017.09.024
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000413540400009&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - http://hdl.handle.net/10044/1/54219
VL  - 471
ER  -
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