Isotopic evidence for palaeowaters in the British Isles

doi:10.1016/S0883-2927(97)00038-3

Applied Geochemistry

Volume 12, Issue 6, November 1997, Pages 813-829

https://doi.org/10.1016/S0883-2927(97)00038-3 Get rights and content

Abstract

Before the 20th century, groundwater circulation in the aquifers of the British Isles had largely adjusted to the temperate maritime climate and sea levels established over the past 10 ka since the end of the Pleistocene. However, in the last 100 a this natural regime has been disturbed by abstraction of water for public supply and industrial use, and palaeowaters from earlier recharge episodes are now becoming a factor to be considered in water balance estimates. This paper presents a synthesis of the existing palaeowater distribution in the British Isles, based on isotopic evidence (δ¹⁸O, δ²H and and¹⁴C). As such, it has relevance to palaeoclimatic studies in addition to the water resource implications.

The Triassic basins of England and Northern Ireland contain saline waters beyond the range¹⁴C dating (>; 40 ka). Stable isotopic ratios show enrichment in some basins and depletion in others, without an overall pattern that would explain all the observed compositions. The results for the Wessex basin suggest recharge in pre-Quaternary times, but for the other basins some flushing by Pleistocene or Holocene meteoric waters is indicated. Isolated occurrences of apparently long-residence waters are found elsewhere throughout the British Isles, for example from Carboniferous and Lower Palaeozoic strata. In such cases, environmental isotopes are more useful as constraints on hydrogeological models than as indicators of palaeoconditions.

Major water supply aquifers are restricted almost entirely to England. The two sandstone formations (Triassic Sherwood Sandstone and Cretaceous Lower Greensand) have a greater range of stable isotopic values between phreatic and confined conditions than the two carbonate formations (Jurassic Lincolnshire Limestone and Cretaceous Chalk). This indicates that the sandstone aquifers are better archives of information on palaeoconditions than the carbonate aquifers. They show that atmospheric circulation patterns over Britain have probably remained the same since the late Pleistocene. However,¹⁴C data from all four of the major aquifers emphasise the hiatus in recharge during periglacial conditions which occurred between the late Pleistocene and early Holocene.

Reference (57)

AndrewsJ.N. et al.
Inert gases in groundwater from the Bunter Sandstone of England as indicators of age and palaeoclimatic trends
Journal of Hydrology
(1979)
AndrewsJ.N. et al.
²³⁴U²³⁸U activity ratios of dissolved uranium in groundwaters from a Jurassic Limestone aquifer in England
Earth and Planetary Science Letters
(1982)
AndrewsJ.N. et al.
Chlorine-36 in groundwater as a palaeoclimatic indicator: the East Midlands Triassic sandstone aquifer (UK)
Earth and Planetary Science Letters
(1994)
BathA.H. et al.
Identification of connate water in interstitial solution of Chalk sediments
Geochimica et Cosmochimica Acta
(1981)
BishopP.K. et al.
Chemical and isotopic evidence for the hydrogeological processes occurring in the Lincolnshire Limestone
Journal of Hydrology
(1990)
BishopP.K. et al.
Use of¹⁴C modelling to determine vulnerability and pollution of a carbonate aquifer: the Lincolnshire Limestone, Eastern England
Applied Geochemistry
(1991)
DowningR.A. et al.
The age of groundwater in the Lincolnshire Limestone, England and its relevance to the flow mechanism
EdmundsW.M. et al.
Baseline geochemical conditions in the Chalk aquifer, Berkshire, UK: a basis for groundwater quality management
Applied Geochemistry
(1987)
HiscockK.M.
The influence of pre-Devensian glacial deposits on the hydrogeochemistry of the Chalk aquifer system of north Norfolk, UK
Journal of Hydrology
(1993)
HiscockK.M. et al.
Hydrochemical and stable isotopic evidence for the extent and nature of the effective Chalk aquifer of north Norfolk, UK
Journal of Hydrology
(1996)

HoritaJ. et al.

The activity-composition relationship of oxygen and hydrogen isotopes in aqueous salt solutions: I. Vapor-liquid water equilibration of single-salt solutions from 50 to 100°C

Geochimica et Cosmochimica Acta

(1993)

KharakaY.K. et al.

Oxygen and hydrogen isotope geochemistry of deep basin brines

MookW.G.

Carbon-14 in hydrogeological studies

SmalleyP.C. et al.

⁸⁷Sr/⁸⁶Sr in waters from the Lincolnshire Limestone aquifer, England, and the potential of natural strontium isotopes as a tracer for a secondary seawater injection process in oilfields

Applied Geochemistry

(1988)

AlexanderJ. et al.

Hydrogeological Investigations in the Harwell Region: The Use of Environmental Isotopes, Inert Gas Contents and the Uranium Decay Series

British Geological Survey ReportFLPU 8487

(1984)

AndrewsJ.N. et al.

Dissolved gases as indicators of groundwater mixing in a Jurassic Limestone aquifer

AndrewsJ.N. et al.

The thermal springs of Bath

Nature

(1982)

AndrewsJ.N. et al.

Environmental Isotope Studies in Two Aquifer Systems: a comparison of groundwater dating methods

BathA.H.

Stable isotope evidence for palaeorecharge conditions of groundwater

BathA.H.

Hydrochemical characterisation of argillaceous rocks

BathA.H. et al.

Palaeoclimatic trends deduced from the hydrochemistry of a Triassic sandstone aquifer, United Kingdom

BathA.H. et al.

The age of groundwaters in the Chalk and Pleistocene sands of north-east Suffolk

British Geological Survey Report No.WD/ST/85/1

(1985)

BathA.H. et al.

Groundwater chemistry in the Sellafield area: a preliminary interpretation

Quarterly Journal of Engineering Geology

(1996)

BennisonG.M. et al.

The Geological History of the British Isles

BurdonD.J.

Geothermal investigations in Ireland

ColemanM.L. et al.

Reduction of water with zinc for hydrogen isotope analysis

Analytical Chemistry

(1982)

CraigH.

Isotopic variations in meteoric waters

Science

(1961)

CustodioE.

Hydrogeological and hydrochemical aspects of aquifer overexploitation

Cited by (77)

Using environmental tracers to evaluate the preservation of palaeoclimate signals in aquifers of the London Basin, UK
2023, Journal of Hydrology
The concept of aquifer basins as palaeoclimate archives has existed for some decades, yet few detailed studies comparing aquifer types have been carried out. To assess the potential of a particular aquifer as an archive, its hydrogeochemical characteristics must be thoroughly investigated, ideally in comparison to an adjacent aquifer which can be shown to substantially preserve its ice-age endowment at depth. The London Basin (UK) presents such an opportunity, containing two main aquifers of contrasting type: the Chalk, a fractured microporous limestone, and the Lower Greensand, a porous sandstone. Despite intensive exploitation of both, evidence for Devensian (late-glacial) water remains at depth, though this differs between aquifer type. To understand the reasons for this, a suite of environmental tracers has been applied. In addition to hydrochemistry, stable isotopes (δ¹⁸O, δ²H), carbon isotopes (δ¹³C-DIC, ¹⁴C-DIC) and noble gases (He, Ne, Ar, Kr and Xe), two tracers new to the basin (CFCs and ¹⁴C-DOC) have been used. In effect the Lower Greensand appears to be the ‘reference aquifer’, preserving recharge from prior to the Last Glacial Maximum (LGM), while the Chalk contains mixed water, with no remaining trace of the undiluted pre-LGM end member even at depth in remote parts of the confined basin. Whereas both aquifers had in the past given maximum ¹⁴C-DIC model ages ≥ 30 kyr (the effective limit of that method), in the present study the use of ¹⁴C-DOC has reduced this to 23.4 kyr (Lower Greensand) and 17.2 kyr (Chalk). Similar contrasts in maximum stable isotope depletions (−8.2 ‰ and −7.8 ‰ δ¹⁸O) and noble-gas-derived recharge temperature minima (2.6° and 4.1 °C) were also observed. CFCs were found at all Chalk sites, with traces detectable even at 40 km from outcrop, so some climate signal degradation appears inevitable throughout the Chalk aquifer of the basin. A correlation between ¹⁴C activity and excess ⁴He suggests that deep saline water in the Lower Greensand could be ≥ 50 kyr old. The use of ¹⁴C-DOC in particular appears to be key to understanding how reliable these individual aquifers are as palaeoarchives.
1D-4D electrical and electromagnetic methods revealing fault-controlled aquifer geometry and saline water uprising
2021, Journal of Hydrology
This paper presents new results of 1D-4D electrical resistivity and electromagnetic surveys for the delineation of aquifer geometry and the detection of saline paleo-water uprising along structural discontinuities. These geophysical surveys were undertaken at the alluvial aquifer of the Oltrepò Pavese plain sector (Po Valley, Northern Italy). At the investigated test site, the alluvial aquifer is strongly conditioned by the presence of an important tectonic discontinuity whose localization and trace were better defined by this study. This fault is responsible for the sudden deepening that affects the bedrock and is also responsible for the uprising of deep, saline paleo-waters which strongly influences the chemistry of groundwater.
During the campaign a variety of experimental setups were tested. This provided an ideal opportunity to cross-validate geophysical results with extensive ground truth provided by groundwater sampling and stratigraphic, electrical conductivity, temperature and redox potential logs undertaken within the wells. It also permitted an assessment of the usability of electrical and electromagnetic surveys in such a complex hydrogeological setting.
Geophysical surveys revealed the presence of sharp and irregular contact between the alluvial aquifer and the underlying bedrock. This is characterized by morphological irregularities, which are likely to have been shaped either by tectonics and/or by the paleo-river’s erosion. The bedrock is affected by saline water contaminations which are likely localized along structural discontinuities which represent and facilitate the flow towards the alluvial aquifer. Detailed 3D and time-lapse imaging revealed irregular-shaped shallow saline water contaminations within the alluvial aquifer, as well as temporal variability of groundwater salinity. Spatial distribution of contaminations and salinity degree are likely to be affected by different factors like the aperture of the discontinuities within the bedrock, the hydraulic conductivity of the aquifer, as well as seasonal variations in terms of fresh water recharge.
Subsurface hydrological processes and groundwater residence time in a coastal alluvium aquifer: Evidence from environmental tracers (δ18O, δ2H, CFCs, 3H) combined with hydrochemistry
2020, Science of the Total Environment
As an important part of the water cycle, the hydrologic process and chemical compositions of groundwater have changed significantly due to the joint influence of climate change and human activities. Groundwater salinization becomes a serious threat to water security in coastal areas. In order to assess the relationships between surface water, groundwater and seawater in the coastal plain, we performed a synthesis study based on hydrochemical-isotopic data, hydro-dynamical records and environmental tracers. Deuterium and oxygen isotopes and water chemical indicators were used to identify pollution status, salt sources and migration processes. Radioactive isotopes and gaseous tracers were used to obtain reasonable groundwater age. With the help of multi-tracer approach, the surface-groundwater interaction, salinization of groundwater and nitrate pollution were identified in the Yang-Dai River plain, northern China. The estimated groundwater ages determined from chlorofluorocarbons (CFCs) and tritium (³H) ranges from 18 to 41 years in this area, suggesting a modern groundwater circulation. The spatial distribution of the groundwater age varies significantly due to horizontal hydrogeological heterogeneity. The total dissolved solids (TDS) content of the groundwater near the Well Field (average: 970 mg/L) was higher than the TDS values in samples derived from places located at an equivalent distance to the coastal line (average is 708 mg/L), which resulted from the vertical seawater intrusion through river channels and pollutant inputs from agriculture activities. The nitrate concentrations in groundwater were elevated up to 271 mg/L and increased with increasing groundwater age, which was another water environment problem that should be solved urgently but lacks sufficient attention for years. This study provides a conceptual model with a number of comparable hydrochemical information, which is significant for regional pollution control and water resources management.
Population structure and dynamics of the Atlantic mackerel (Scomber scombrus) in the North Atlantic inferred from otolith chemical and shape signatures
2020, Fisheries Research
The Atlantic mackerel, Scomber scombrus, is an economically important and widely distributed fish species in the North Atlantic, currently considered to comprise two stocks: the North-West Atlantic (NWA) and the North-East Atlantic (NEA). Each stock is composed of different spawning components which involve temporal and spatial movements driven by the environment. Thus, resolving the species population structure and dynamics presents a challenge to scientists. In this study, the stock structure of S. scombrus was evaluated using otolith shape and chemical signatures. One hundred and eighty individuals of the same cohort (age 3), caught between January and February of 2018 from six key locations in the North Atlantic, were used. Individuals were collected from the two spawning components in the NWA stock, the Canadian Northern component (NWA-N) and the US Southern component (NWA-S); and from the three spawning components in the NEA stock, the North Sea (NEA-NS), the Western (NEA-W) and the Southern components (NEA-S), plus, an overlapping area of these last two components, the Bay of Biscay (NEA-BB). Combined otolith signatures fully discriminated the NEA and NWA stocks (100% of reclassification success, indicates distinct population-units) and discriminated the components within each stock with high reclassification percentages (100% and 68% for the overall reclassification of the NWA and NEA components, respectively). These data suggest that NWA stock should be regard as two distinct population-units for fisheries management purposes, confirms the complex metapopulational structure of the NEA stock, and calls for the need of continuous evaluation of these complex stocks in order to achieve a sustainable exploitation.
Paleoclimatic investigations using isotopic signatures of the Late Pleistocene-Holocene groundwater of the stratified aquifers in Kuwait
2020, Journal of Hydrology
Citation Excerpt :
The results were derived mainly by analyzing the value of d-excess, δ18O and δD of groundwater along with 14C. Climatic change during the Late Quaternary has been inferred from the isotopic composition of groundwater in various places all over the world, in Africa (Fontes et al., 1991; Edmunds et al., 1999; Bakari et al., 2012); North America (Stute et al., 1992; Dutton, 1995; Castro and Goblet, 2003; Hough et al., 2014); Asia (Sukhija et al., 1998; Saravana Kumar et al., 2008, Zhao et al 2018); Australia (Love et al., 1994); and Europe (Rozanski, 1985; Darling et al., 1997; Walraevens, 1998; Eiler, 2011; Ettayfi et al., 2012), but so far, no investigation has been carried out in this part of the peninsula. The isotopic investigations carried out so far in Kuwait have been related either to understanding its groundwater flow processes (Hadi et al., 2016; Saravana Kumar, 2013) or deciphering contamination sources (Akber et al., 2006).
The study attempts to determine paleo recharge sources for two major aquifer units of Kuwait, namely, Kuwait Group Aquifer (KGA), and Dammam Formation (DFm) were collected and analyzed for major ions and isotopes. The obtained results of ¹⁴C ages indicated that the groundwater samples ranged from 31.9 Ky to 3.9 Ky in DFm and 23.3 Ky to 0.8 Ky in KGA. The variations in δ¹⁸O signatures with respect to age reflected that there were two major sources of rainwater such as enriched southern Indian Ocean monsoon and the depleted northwesterly (Mediterranean) vapor source. The samples found to show variations during the three marine isotopic stages (MIS 1–3), Heinrich events, Bolling-Allerod, and Dryas time periods in both aquifers. A shift in the Intertropical convergence zone (ITCZ) was witnessed in the groundwater of both aquifers from 7.8 Ky to 4.9 Ky. The variation in the Holocene climate is mainly due to the influence of tropospheric easterly jet governed by the swing in ITCZ , as a result of Holocene volcanism. The mean δ¹⁸O values of DFm samples (-3.81‰) reflect depletion than KGA samples (-2.31‰), and the d-excess values were −0.95‰ and 2.05‰ respectively. Thus it could be inferred that the DFm was predominantly recharged during Late Pleistocene period and it was in a relatively cooler climate than recharge environment of KGA. The study infers that KGA was recharged between 26^oN and 26.8^oN latitudes, and that of the DFm was noted to be recharged (south west of Kuwait) in two different patches between 25.8^oN and 26.2^oN and 26.7^oN-27.4^oN latitudes during Late Pleistocene. The KGA was concluded to be recharged between 25.5^oN and 27.5^oN latitudes, south of Kuwait, during Holocene.
Moisture sources and climate evolution during the last 30 kyr in northeastern Tibetan Plateau: Insights from groundwater isotopes (2H, 18O, 3H and 14C) and water vapour trajectories modeling
2020, Quaternary Science Reviews
Understanding the past hydrological cycle and climate change may contribute to the sustainable utilization of water resources. Here we combined groundwater stable isotopes (²H and ¹⁸O), age dating (³H and ¹⁴C) and water vapour transport trajectories modeling to reveal the moisture source and climate evolution over the last 30 kyr in southeastern Qaidam Basin, northeast Tibetan Plateau. The compositions of δD and δ¹⁸O indicated that the groundwater was mainly recharged by precipitation and snowmelt water from the East Kunlun Mountains in the south. The groundwater stable isotopes exhibited a depleted trend from west to east across the four catchments of the basin which seemed not to alter since the late stage of the Late Pleistocene. A combination of the deuterium excess (d-excess) of groundwater and present-day moisture source modeling revealed that the moisture source had been dominated by the Westerlies without obvious impact of the summer monsoon since the last 30 kyr. The enriched δD and δ¹⁸O of groundwater during the Holocene suggested a warmer climate than the late stage of the Late Pleistocene, which seemed not to be accompanied by moisture source variations. The results of this study could be helpful for both climate change and water resource research in this region or even, over the entire Tibetan Plateau.

View all citing articles on Scopus

View full text

Isotopic evidence for palaeowaters in the British Isles

Abstract

Journal of Hydrology

Earth and Planetary Science Letters

Earth and Planetary Science Letters

Geochimica et Cosmochimica Acta

Journal of Hydrology

Applied Geochemistry

Applied Geochemistry

Journal of Hydrology

Journal of Hydrology

Geochimica et Cosmochimica Acta

Applied Geochemistry

Hydrogeological Investigations in the Harwell Region: The Use of Environmental Isotopes, Inert Gas Contents and the Uranium Decay Series

British Geological Survey ReportFLPU 8487

Dissolved gases as indicators of groundwater mixing in a Jurassic Limestone aquifer

The thermal springs of Bath

Nature

Environmental Isotope Studies in Two Aquifer Systems: a comparison of groundwater dating methods

Stable isotope evidence for palaeorecharge conditions of groundwater

Hydrochemical characterisation of argillaceous rocks

Palaeoclimatic trends deduced from the hydrochemistry of a Triassic sandstone aquifer, United Kingdom

The age of groundwaters in the Chalk and Pleistocene sands of north-east Suffolk

British Geological Survey Report No.WD/ST/85/1

Groundwater chemistry in the Sellafield area: a preliminary interpretation

Quarterly Journal of Engineering Geology

The Geological History of the British Isles

Geothermal investigations in Ireland

Reduction of water with zinc for hydrogen isotope analysis

Analytical Chemistry

Isotopic variations in meteoric waters

Science

Hydrogeological and hydrochemical aspects of aquifer overexploitation