Hydrogeochemical indications of regional flow in the Lower Greensand aquifer of the London Basin

Darling, W. George; Lewis, Melinda A.. 2021 Hydrogeochemical indications of regional flow in the Lower Greensand aquifer of the London Basin. Quarterly Journal of Engineering Geology and Hydrogeology, 55 (2), qjegh2021-028. https://doi.org/10.1144/qjegh2021-028

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Official URL: http://dx.doi.org/10.1144/qjegh2021-028

Abstract/Summary

The Lower Greensand (LGS) forms the second most important aquifer in the London Basin but, being largely absent beneath the city itself, has received much less attention than the ubiquitous overlying Chalk aquifer. While the general directions of groundwater flow in the Chalk are well established, there has been much less certainty about flow in the LGS owing to regionally sparse borehole information. This study focuses on two hitherto uncertain aspects of the confined aquifer: the sources of recharge to the west-central London Basin around Slough, and the fate of LGS water where the aquifer thins out on the flank of the London Platform in the Gravesend–Medway–Sheppey area on the southern side of the basin. The application of hydrogeochemical techniques including environmental isotopes indicates that recharge to the Slough area is derived from the northern LGS outcrop, probably supplemented by downward leakage from the Chalk, while upward leakage from the LGS in North Kent is mixing with Chalk water to the extent that some Chalk boreholes on the Isle of Sheppey are abstracting high proportions of water with an LGS fingerprint. In doing so, this study demonstrates the value of re-examining previously published data from a fresh perspective.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1144/qjegh2021-028
ISSN:	1470-9236
Additional Keywords:	GroundwaterBGS, Groundwater
Date made live:	27 Sep 2021 12:27 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/531112

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1144/qjegh2021-028

ISSN:

1470-9236

Additional Keywords:

GroundwaterBGS, Groundwater

Date made live:

27 Sep 2021 12:27 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/531112