Geochemical methods in studies of recent and past environmental changes
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Date
2013-11-17
Authors
Journal Title
Journal ISSN
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Publisher
The Association of Applied Geochemists
Abstract
A multi‐proxy approach is advocated in studies of recent and past environmental changes, as the use of too few diagnostic criteria often leads to misinterpretations. Geochemistry is a powerful tool which, when combined with other proxies, can provide information on short‐ and long‐term
changes preserved in the sedimentary record.
Geochemical methods used in the studies
presented here include ion chromatography, ICPAES, ICP‐MS, portable‐XRF and X‐ray core
scanning. While IC, ICP‐AES and ICP‐MS are well established techniques, P‐XRF and X‐ray core scanning have only recently been used in
geosciences, particularly in Australasia. The latter, coupled with magnetic susceptibility, produces a continuous record along the length of a core with high resolution fingerprinting of environmental
changes, albeit with qualitative data. Portable‐XRF is a rapid non‐destructive method, but results are semi‐quantitative. Here we discuss the application of these two methods in recent studies.Long‐ and short‐term environmental changes in Moawhitu Wetland, d’Urville Island, New Zealand,
were reconstructed using a suite of multi‐proxy analyses. It was high resolution X‐ray core scanning though that provided the geochemical evidence for tsunami inundation into the wetland, beyond the extent of any sand deposit. ICP‐AES and ICP‐MS analyses of selected samples were also used to quantify and corroborate the results of the X‐ray core scanning.
saltwater is more commonly used in
archaeological studies, although it has recently been used to map the inundation limit following the 2011 Tohoku‐oki tsunami, and to assess the longevity of marine chemical markers in different sediment types. Concurrent analyses of waterleachable
ions by IC and ICP‐AES were also used to
corroborate the results of p‐XRF analysis,
confirming the occurrence of saltwater indicators in the sediment.
Description
Keywords
Environmental effects, Geochemistry, Sediments, Chromatography, Australia, Wetlands
Citation
Chagué-Goff, C., Wong, H. K. Y., Gadd, P., Cohen, D., & Cope, J. (2013). Geochemical methods in studies of recent and past environmental changes. Paper presented at the 26th International Applied Geochemistry Symposium 17 – 21 November 2013
Rotorua, New Zealand.