Title

Sediment radioisotope dating across a stratigraphic discontinuity in a mining-impacted lake

Document Type

Article

Publication Date

1-1-2007

Abstract

Application of radioisotope sediment dating models to lakes subjected to large anthropogenic sediment inputs can be problematic. As a result of copper mining activities, Torch Lake received large volumes of sediment, the characteristics of which were dramatically different from those of the native sediment. Commonly used dating models (CIC-CSR, CRS) were applied to Torch Lake, but assumptions of these methods are violated, rendering sediment geochronologies inaccurate. A modification was made to the CRS model, utilizing a distinct horizon separating mining from post-mining sediment to differentiate between two focusing regimes. 210Pb inventories in post-mining sediment were adjusted to correspond to those in mining-era sediment, and a sediment geochronology was established and verified using independent markers in 137Cs accumulation profiles and core X-rays. © 2006 Elsevier Ltd. All rights reserved.

Publication Title

Journal of Environmental Radioactivity

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