Integrating petrography, mineralogy and hydrochemistry to constrain the influence and distribution of groundwater contributions to baseflow in poorly productive aquifers

Insights from Gortinlieve catchment, Co. Donegal, NW Ireland

John Caulfield, Merlyn Chelliah, Jean-Christophe Comte, Rachel Cassidy, Raymond Flynn

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Identifying groundwater contributions to baseflow forms an essential part of surface water body characterisation. The Gortinlieve catchment (5 km2) comprises a headwater stream network of the Carrigans River, itself a tributary of the River Foyle, NW Ireland. The bedrock comprises poorly productive metasediments that are characterised by fracture porosity. We present the findings of a multi-disciplinary study that integrates new hydrochemical and mineralogical investigations with existing hydraulic, geophysical and structural data to identify the scales of groundwater flow and the nature of groundwater/bedrock interaction (chemical denudation). At the catchment scale, the development of deep weathering profiles is controlled by NE-SW regional scale fracture zones associated with mountain building during the Grampian orogeny. In-situ chemical denudation of mineral phases is controlled by micro- to meso-scale fractures related to Alpine compression during Palaeocene to Oligocene times. The alteration of primary muscovite, chlorite (clinochlore) and albite along the surfaces of these small-scale fractures has resulted in the precipitation of illite, montmorillonite and illite-montmorillonite clay admixtures. The interconnected but discontinuous nature of these small-scale structures highlights the role of larger scale faults and fissures in the supply and transportation of weathering solutions to/from the sites of mineral weathering. The dissolution of primarily mineral phases releases the major ions Mg, Ca and HCO3 that are shown to subsequently form the chemical makeup of groundwaters. Borehole groundwater and stream baseflow hydrochemical data are used to constrain the depths of groundwater flow pathways influencing the chemistry of surface waters throughout the stream profile. The results show that it is predominantly the lower part of the catchment, which receives inputs from catchment/regional scale groundwater flow, that is found to contribute to the maintenance of annual baseflow levels. This study identifies the importance of deep groundwater in maintaining annual baseflow levels in poorly productive bedrock systems.
Original languageEnglish
Pages (from-to)224-234
Number of pages11
JournalScience of the Total Environment
Volume500-501
Early online date15 Sep 2014
DOIs
Publication statusPublished - 1 Dec 2014

Fingerprint

Hydrochemistry
Petrography
hydrochemistry
Mineralogy
baseflow
petrography
Aquifers
Catchments
Groundwater
mineralogy
Groundwater flow
aquifer
catchment
Weathering
groundwater
groundwater flow
Minerals
Bentonite
bedrock
denudation

Keywords

  • poorly productive bedrock aquifers
  • fracture porosity
  • weathering
  • clay
  • groundwater
  • baseflow

Cite this

@article{80797ecf8ed3419ea2533a52f64dc11c,
title = "Integrating petrography, mineralogy and hydrochemistry to constrain the influence and distribution of groundwater contributions to baseflow in poorly productive aquifers: Insights from Gortinlieve catchment, Co. Donegal, NW Ireland",
abstract = "Identifying groundwater contributions to baseflow forms an essential part of surface water body characterisation. The Gortinlieve catchment (5 km2) comprises a headwater stream network of the Carrigans River, itself a tributary of the River Foyle, NW Ireland. The bedrock comprises poorly productive metasediments that are characterised by fracture porosity. We present the findings of a multi-disciplinary study that integrates new hydrochemical and mineralogical investigations with existing hydraulic, geophysical and structural data to identify the scales of groundwater flow and the nature of groundwater/bedrock interaction (chemical denudation). At the catchment scale, the development of deep weathering profiles is controlled by NE-SW regional scale fracture zones associated with mountain building during the Grampian orogeny. In-situ chemical denudation of mineral phases is controlled by micro- to meso-scale fractures related to Alpine compression during Palaeocene to Oligocene times. The alteration of primary muscovite, chlorite (clinochlore) and albite along the surfaces of these small-scale fractures has resulted in the precipitation of illite, montmorillonite and illite-montmorillonite clay admixtures. The interconnected but discontinuous nature of these small-scale structures highlights the role of larger scale faults and fissures in the supply and transportation of weathering solutions to/from the sites of mineral weathering. The dissolution of primarily mineral phases releases the major ions Mg, Ca and HCO3 that are shown to subsequently form the chemical makeup of groundwaters. Borehole groundwater and stream baseflow hydrochemical data are used to constrain the depths of groundwater flow pathways influencing the chemistry of surface waters throughout the stream profile. The results show that it is predominantly the lower part of the catchment, which receives inputs from catchment/regional scale groundwater flow, that is found to contribute to the maintenance of annual baseflow levels. This study identifies the importance of deep groundwater in maintaining annual baseflow levels in poorly productive bedrock systems.",
keywords = "poorly productive bedrock aquifers, fracture porosity, weathering, clay, groundwater, baseflow",
author = "John Caulfield and Merlyn Chelliah and Jean-Christophe Comte and Rachel Cassidy and Raymond Flynn",
note = "Mark Russell is thanked for analytical assistance with powder XRD analysis and the discussion of results. Robbie Goodhue kindly provided access to the TCD collection of Clay Mineral Society Source Clays. John Meneely and Pat McBride from the School of Geography, Archaeology and Palaeoecology (QUB) are thanked for assistance with the separation of the < 2 μm clay fraction and the preparation of polished thin sections respectively. John Finn and Zuansi Cai provided help with sampling during the 2013 field season. Marie Archbold and Alison Orr provided useful information on sampling and sample details for 2010–2012 baseflow monitoring. Discussion of Gortinlieve bedrock geology with Janka Nitsche and Katarina Pilatova helped to identify suitable field outcrops. J.C. gratefully acknowledges the support of the Queen's University Researcher Training and Development Fund for the FTIR analyses. The comments of three anonymous reviewers helped to improve the clarity of the manuscript. Damia Barcelo is thanked for his editorial assistance. This study was undertaken as part of a research grant funded by the Irish Department of Communications, Energy and Natural Resources under the National Geoscience Programme 2007–2013. The views expressed are the authors' own and do not necessarily reflect the views and opinions of the Minister for Communications, Energy and Natural Resources.",
year = "2014",
month = "12",
day = "1",
doi = "10.1016/j.scitotenv.2014.08.105",
language = "English",
volume = "500-501",
pages = "224--234",
journal = "Science of the Total Environment",
issn = "0048-9697",
publisher = "Elsevier",

}

TY - JOUR

T1 - Integrating petrography, mineralogy and hydrochemistry to constrain the influence and distribution of groundwater contributions to baseflow in poorly productive aquifers

T2 - Insights from Gortinlieve catchment, Co. Donegal, NW Ireland

AU - Caulfield, John

AU - Chelliah, Merlyn

AU - Comte, Jean-Christophe

AU - Cassidy, Rachel

AU - Flynn, Raymond

N1 - Mark Russell is thanked for analytical assistance with powder XRD analysis and the discussion of results. Robbie Goodhue kindly provided access to the TCD collection of Clay Mineral Society Source Clays. John Meneely and Pat McBride from the School of Geography, Archaeology and Palaeoecology (QUB) are thanked for assistance with the separation of the < 2 μm clay fraction and the preparation of polished thin sections respectively. John Finn and Zuansi Cai provided help with sampling during the 2013 field season. Marie Archbold and Alison Orr provided useful information on sampling and sample details for 2010–2012 baseflow monitoring. Discussion of Gortinlieve bedrock geology with Janka Nitsche and Katarina Pilatova helped to identify suitable field outcrops. J.C. gratefully acknowledges the support of the Queen's University Researcher Training and Development Fund for the FTIR analyses. The comments of three anonymous reviewers helped to improve the clarity of the manuscript. Damia Barcelo is thanked for his editorial assistance. This study was undertaken as part of a research grant funded by the Irish Department of Communications, Energy and Natural Resources under the National Geoscience Programme 2007–2013. The views expressed are the authors' own and do not necessarily reflect the views and opinions of the Minister for Communications, Energy and Natural Resources.

PY - 2014/12/1

Y1 - 2014/12/1

N2 - Identifying groundwater contributions to baseflow forms an essential part of surface water body characterisation. The Gortinlieve catchment (5 km2) comprises a headwater stream network of the Carrigans River, itself a tributary of the River Foyle, NW Ireland. The bedrock comprises poorly productive metasediments that are characterised by fracture porosity. We present the findings of a multi-disciplinary study that integrates new hydrochemical and mineralogical investigations with existing hydraulic, geophysical and structural data to identify the scales of groundwater flow and the nature of groundwater/bedrock interaction (chemical denudation). At the catchment scale, the development of deep weathering profiles is controlled by NE-SW regional scale fracture zones associated with mountain building during the Grampian orogeny. In-situ chemical denudation of mineral phases is controlled by micro- to meso-scale fractures related to Alpine compression during Palaeocene to Oligocene times. The alteration of primary muscovite, chlorite (clinochlore) and albite along the surfaces of these small-scale fractures has resulted in the precipitation of illite, montmorillonite and illite-montmorillonite clay admixtures. The interconnected but discontinuous nature of these small-scale structures highlights the role of larger scale faults and fissures in the supply and transportation of weathering solutions to/from the sites of mineral weathering. The dissolution of primarily mineral phases releases the major ions Mg, Ca and HCO3 that are shown to subsequently form the chemical makeup of groundwaters. Borehole groundwater and stream baseflow hydrochemical data are used to constrain the depths of groundwater flow pathways influencing the chemistry of surface waters throughout the stream profile. The results show that it is predominantly the lower part of the catchment, which receives inputs from catchment/regional scale groundwater flow, that is found to contribute to the maintenance of annual baseflow levels. This study identifies the importance of deep groundwater in maintaining annual baseflow levels in poorly productive bedrock systems.

AB - Identifying groundwater contributions to baseflow forms an essential part of surface water body characterisation. The Gortinlieve catchment (5 km2) comprises a headwater stream network of the Carrigans River, itself a tributary of the River Foyle, NW Ireland. The bedrock comprises poorly productive metasediments that are characterised by fracture porosity. We present the findings of a multi-disciplinary study that integrates new hydrochemical and mineralogical investigations with existing hydraulic, geophysical and structural data to identify the scales of groundwater flow and the nature of groundwater/bedrock interaction (chemical denudation). At the catchment scale, the development of deep weathering profiles is controlled by NE-SW regional scale fracture zones associated with mountain building during the Grampian orogeny. In-situ chemical denudation of mineral phases is controlled by micro- to meso-scale fractures related to Alpine compression during Palaeocene to Oligocene times. The alteration of primary muscovite, chlorite (clinochlore) and albite along the surfaces of these small-scale fractures has resulted in the precipitation of illite, montmorillonite and illite-montmorillonite clay admixtures. The interconnected but discontinuous nature of these small-scale structures highlights the role of larger scale faults and fissures in the supply and transportation of weathering solutions to/from the sites of mineral weathering. The dissolution of primarily mineral phases releases the major ions Mg, Ca and HCO3 that are shown to subsequently form the chemical makeup of groundwaters. Borehole groundwater and stream baseflow hydrochemical data are used to constrain the depths of groundwater flow pathways influencing the chemistry of surface waters throughout the stream profile. The results show that it is predominantly the lower part of the catchment, which receives inputs from catchment/regional scale groundwater flow, that is found to contribute to the maintenance of annual baseflow levels. This study identifies the importance of deep groundwater in maintaining annual baseflow levels in poorly productive bedrock systems.

KW - poorly productive bedrock aquifers

KW - fracture porosity

KW - weathering

KW - clay

KW - groundwater

KW - baseflow

U2 - 10.1016/j.scitotenv.2014.08.105

DO - 10.1016/j.scitotenv.2014.08.105

M3 - Article

VL - 500-501

SP - 224

EP - 234

JO - Science of the Total Environment

JF - Science of the Total Environment

SN - 0048-9697

ER -