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Investigating contemporary and historical sediment inputs to Slapton Higher Ley: an analysis of the robustness of source ascription methods when applied to lake sediment data

Jenns, N. and Heppell, C.M. and Burt, Tim P. and Walden, J. and Foster, Ian D.L. (2002) Investigating contemporary and historical sediment inputs to Slapton Higher Ley: an analysis of the robustness of source ascription methods when applied to lake sediment data. Hydrological Processes, 16 (17). pp. 3467-3486. ISSN 0885-6087

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Official URL: http://dx.doi.org/10.1002/hyp.1110

Abstract

This paper reports the results of a quantitative source analysis of the contemporary and historical sediments delivered to Slapton Higher Ley (Devon, UK). Contemporary suspended and bedload sediment inputs to the Higher Ley were apportioned successfully using R- and Q-mode analysis and an unmixing model. Pasture topsoil was responsible for 80% of the suspended sediment load during stormflow, but only 50% under baseflow conditions. Channel bank material dominated bedload (70-80%). Dating by 137Cs of three cores from the Higher Ley indicates that rapid sedimentation has occurred since the 1950s and that pasture topsoil has been the dominant source of sediment deposited in the Higher Ley since the early 1980s. Both the unmixing model and R- and Q-mode analysis support this interpretation. However, the robustness and validity of applying such source ascription techniques to the sediment cores of the Higher Ley is debatable, as chemical and mineral magnetic signatures in the cores are diluted in comparison with sediment sources from the Slapton catchment. Particles-size effects, selective transport and post-depositional physical and chemical processes are examined as possible causes of this dilution effect. Post-depositional alteration of the sediment was identified as the most probable explanation, but further analysis of the process was not possible within the scope of this study.

Item Type:Article
Research Community:University of Westminster > Life Sciences, School of
ID Code:5986
Deposited On:12 Feb 2009 11:32
Last Modified:16 Dec 2009 12:44

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