Long-term Holocene groundwater fluctuations in a chalk catchment: evidence from Rock-Eval pyrolysis of riparian peats

Newell, Andrew J.; Vane, Christopher H. ORCID: https://orcid.org/0000-0002-8150-3640; Sorensen, James P.R.; Moss-Hayes, Vicky; Gooddy, Daren C.. 2016 Long-term Holocene groundwater fluctuations in a chalk catchment: evidence from Rock-Eval pyrolysis of riparian peats. Hydrological Processes, 30 (24). 4556-4567. https://doi.org/10.1002/hyp.10903

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Official URL: http://dx.doi.org/10.1002/hyp.10903

Abstract/Summary

he depositional history of peat-dominated wetlands can be used to understand palaeoclimate and palaeohydrology and also constrain the impacts of future climate change. However, in chalkland valleys, seasonal water table fluctuations and a high alkalinity have diminished key environment indicators such as pollen, and there is a need for alternative investigative techniques. The method of Rock-Eval pyrolysis can track changes in organic matter source and degradation, potentially relating to historic changes in vegetation cover. This is the first Rock-Eval on cores from a groundwater-dependent riparian chalk valley wetland combined with radiocarbon dating. The dating showed that the cores represented approximately 4000 years of depositional history. Changes in hydrocarbon chemistry including normal alkane composition of the peat indicated shifts of around 500 to 1000 years between terrestrial and more aquatic species, relating to periods of climate wetness. These climatic shifts are broadly consistent with other evidence from ombrotrophic peatland and lacustrine sediments across northwest Europe. However, the connection between climate wetness and groundwater dependent chalkland wetlands is complicated by external anthropogenically driven factors relating to land use and vegetation cover changes in the catchment. Nonetheless, this study suggests that Rock-Eval pyrolysis is a useful and cost-effective tool that can provide evidence for long-term Holocene groundwater fluctuations

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1002/hyp.10903
ISSN:	08856087
Additional Keywords:	GroundwaterBGS, Groundwater, Aquifer characterisation, Surface water interaction
Date made live:	13 Jan 2017 13:50 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/515820

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1002/hyp.10903

ISSN:

08856087

Additional Keywords:

GroundwaterBGS, Groundwater, Aquifer characterisation, Surface water interaction

Date made live:

13 Jan 2017 13:50 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/515820