Chloride waters of Great Britain revisited: from subsea formation waters to onshore geothermal fluids

Younger, P. L. , Boyce, A. J. and Waring, A. J. (2015) Chloride waters of Great Britain revisited: from subsea formation waters to onshore geothermal fluids. Proceedings of the Geologists’ Association, 126(4-5), pp. 453-465. (doi: 10.1016/j.pgeola.2015.04.001)

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Abstract

It has long been known that chloride-dominated saline ground waters occur at depth in the UK, not only beneath the sea but also onshore at depths of a few hundred metres. In a few places in northern England, these saline waters discharge naturally at surface in the form of springs. In recent years, however, these saline ground waters have come to be regarded as resources: as potential geothermal fluids intercepted in deep boreholes. Comparisons of the major ions and stable isotopes (δ2H, δ18O and δ34S) of these saline ground waters with North Sea oilfield formation waters, and with brines encountered in former subsea workings of coastal collieries, reveal that they are quite distinct from those found in North Sea oilfields, in that their as δ2H/δ18O signatures are distinctly “meteoric”. δ34S data preclude a significant input from evaporite dissolution – another contrast with many North Sea brines and some colliery waters. Yet, enigmatically, their total dissolved solids contents are far higher than typical meteoric waters. It is tentatively suggested that these paradoxical hydrogeochemical properties might be explained by recharge during Cenozoic uplift episodes, with high concentrations of solutes being derived by a combination of high-temperature rock–water interaction in the radiothermal granites and/or ‘freeze out’ from overlying permafrost that surely formed in this region during cold periods. Geothermometric calculations suggest these saline waters may well be representative of potentially valuable geothermal reservoirs.

Item Type:Articles
Additional Information:The work was funded by NERC Isotope Community Support Facility at SUERC via contract F14/G6/11/01 to Adrian Boyce, Scottish Universities Environmental Research Centre.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Boyce, Professor Adrian and Younger, Professor Paul
Authors: Younger, P. L., Boyce, A. J., and Waring, A. J.
College/School:College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:Proceedings of the Geologists’ Association
Publisher:Elsevier Ltd
ISSN:0016-7878
Copyright Holders:Copyright © 2015 The Authors
First Published:First published in Proceedings of the Geologists’ Association 162(4-5)453-465
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
617381A conceptual hydo geological model for fault related geothermal energy resources in Northern EnglandPaul YoungerNatural Environment Research Council (NERC)NE/I018905/2ENG - ENGINEERING SYSTEMS POWER & ENERGY