Combining multi-scale geophysical techniques for robust hydro-structural characterisation in catchments underlain by hard rock in post-glacial regions

Cassidy, Rachel; Comte, Jean-Christophe; Nitsche, Janka; Wilson, C.; Flynn, Raymond; Ofterdinger, Ulrich

doi:10.1016/j.jhydrol.2014.06.004

Cited by 46 publications

(32 citation statements)

References 51 publications

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“…Gabriel et al () used a combination of seismic, gravity and electrical methods to delineate extent of subglacial valleys and impacts of salt intrusion on the groundwater reservoirs. A number of other studies have shown the strength of multidimensional and multiscale geophysical applications to flow path delineation (e.g., McClymont et al ; Cassidy et al ; Meier et al ), contaminant transport and fate (e.g., Atekwana and Atekwana ; Konstantaki et al ), and karst characterization (e.g., Martínez‐Moreno et al ). While these previous studies demonstrate the capacity of geophysical techniques to understand various hydrogeological and geological problems, few have shown how an integrated, multidisciplinary and multiscaled approach can generate a robust conceptualization of a heterogeneous sedimentary bedrock environment, exhibiting multiple geologic unconformities with contrasting sedimentary rock types and characteristics, with varying hydrological impacts associated with dense nonaqueous phase liquid (DNAPL) migration and source evolution.…”

Section: Introductionmentioning

confidence: 99%

Multidimensional Investigation of Bedrock Heterogeneity/Unconformities at a DNAPL‐Impacted Site

Steelman¹,

Meyer

Parker

2017

Groundwater

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Organic solvent (i.e., dense nonaqueous phase liquid, DNAPL) migration in the subsurface is known to be extremely sensitive to geologic heterogeneity. There is often a focus on heterogeneity that results from changing depositional conditions over short spatial scales. Similar or even more extreme spatial heterogeneity can result postdeposition due to erosional processes. This study applies a synergistic approach based on a combination of high-resolution lithologic logs of continuous cores, borehole geophysical logs, surface electrical resistivity, and seismic refraction tomography models to assess spatial heterogeneity in a shallow bedrock sequence subject to multiple unconformities and contaminated with a mixture of organic chemicals. The persistence of DNAPL in the source zone and an associated dissolved-phase plume led to variable impacts on formation resistivity across the study site. Seismic refraction in combination with electrical resistivity tomography improved interpretation of highly irregular erosional boundaries by delineating sharp lateral transitions in lithologic composition near the source zone and across the dissolved-phase plume. Electrical resistivity was effective at differentiating between clean and mud-rich sandstones and their unconformable contact with an underlying dolostone. Geophysical measurements revealed eroded dolostone mounds encased by a network of younger mud-rich sandstones channelized by clean semi-lithified sand, all of which was buried beneath variable glacial drift. Our synergistic multidimensional approach resulted in the development of a detailed three-dimensional shallow bedrock geospatial model, which has led to an improved understanding of DNAPL migration and contaminant plume heterogeneity.

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Section: Introductionmentioning

confidence: 99%

Multidimensional Investigation of Bedrock Heterogeneity/Unconformities at a DNAPL‐Impacted Site

Steelman¹,

Meyer

Parker

2017

Groundwater

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“…This sandstone-dominated succession represents the UK's second most important aquifer, covering 25% of the total licensed volume of groundwater abstractions in the country (Abesser and Lewis 2015;Binley et al 2002;Bricker et al 2012). Contamination has been detected in the aquifer at relatively shallow (<~150 m BGL) depths due to agricultural activity, and the release of industrial waste and sewage in urban areas (Barrett et al 1999;Bottrell et al 2008;Bloomfield et al 2001;Cassidy et al 2014;Lawrence et al 2006;Rivett et al 2012); furthermore, the Sherwood Sandstone Group hosts important hydrocarbon resources onshore in Dorset (~1,500 m BGL), as well as in the Irish Sea and in the North Sea (McKie and Williams 2009;McKie and Shannon 2011).…”

Section: Hydrogeological Settingmentioning

confidence: 99%

Characterization of a fluvial aquifer at a range of depths and scales: the Triassic St Bees Sandstone Formation, Cumbria, UK

2017

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Fluvial sedimentary successions represent porous media that host groundwater and geothermal resources. Additionally, they overlie crystalline rocks hosting nuclear waste repositories in rift settings. The permeability characteristics of an arenaceous fluvial succession, the Triassic St Bees Sandstone Formation in England (UK), are described, from core-plug to well-test scale up to~1 km depth. Within such lithified successions, dissolution associated with the circulation of meteoric water results in increased permeability (K~10 −1 -10 0 m/day) to depths of at least 150 m below ground level (BGL) in aquifer systems that are subject to rapid groundwater circulation. Thus, contaminant transport is likely to occur at relatively high rates. In a deeper investigation (> 150 m depth), where the aquifer has not been subjected to rapid groundwater circulation, well-test-scale hydraulic conductivity is lower, decreasing from K~10 −2 m/day at 150-400 m BGL to 10 −3 m/day down-dip at~1 km BGL, where the pore fluid is hypersaline. Here, pore-scale permeability becomes progressively dominant with increasing lithostatic load. Notably, this work investigates a sandstone aquifer of fluvial origin at investigation depths consistent with highly enthalpy geothermal reservoirs (~0.7-1.1 km). At such depths, intergranular flow dominates in unfaulted areas with only minor contribution by bedding plane fractures. However, extensional faults represent preferential flow pathways, due to presence of high connective open fractures. Therefore, such faults may (1) drive nuclear waste contaminants towards the highly permeable shallow (< 150 m BGL) zone of the aquifer, and (2) influence fluid recovery in geothermal fields.

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“…Siliciclastic deposits of continental origin can serve as important hosts for hydrocarbon, geothermal, and groundwater resources (Aldinucci, Gandin, & Sandrelli, ; Cassidy et al, ; McKie & Williams, ; Tellam & Barker, ). Mesozoic sedimentary successions of mixed fluvial and aeolian origin host major groundwater aquifers in Europe, as well as in North America (Olivarius et al, ; Swanson, Bahr, Bradbury, & Anderson, ; Tellam, ).…”

Section: Introductionmentioning

confidence: 99%

Sedimentary flow heterogeneities in the Triassic U.K. Sherwood Sandstone Group: Insights for hydrocarbon exploration

2018

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Fluvial and aeolian sedimentary successions host important hydrocarbon resources as well as major groundwater aquifers. This review of the lithological characteristics of Triassic fluvio‐aeolian successions of the Sherwood Sandstone Group (United Kingdom) demonstrates how distance from a fluvial sediment source and rate of rift‐related tectonic subsidence play important roles in governing reservoir quality in continental successions. Increasing distance from the fluvial sediment source area results in increased porosity and permeability in deposits of mixed fluvial and aeolian reservoir successions that accumulated in arid and semiarid settings. Indeed, successions of the U.K. Sherwood Sandstone Group reveal an increase in the proportion of highly permeable deposits of aeolian origin with increasing distance from the principal uplands, represented by the Armorican Massif in northern France, which formed the main source for delivery of fluvial sediment to a series of rift basins. A progressive reduction in the discharge of fluvial systems entering and passing through a series of interlinked rift basins encouraged aeolian accumulation in more distal basins. Extensional tectonics enabled preservation of highly permeable aeolian facies in basins subject to high rates (≳100 m/Myr) of tectonic subsidence by rapidly placing such deposits below the water table. However, successions exclusively characterized by fluvial lithofacies record decreases in both porosity and permeability with increasing distance (~250–750 km) from the sediment source due to the coupling of porosity reduction and increasing clay content.

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Combining multi-scale geophysical techniques for robust hydro-structural characterisation in catchments underlain by hard rock in post-glacial regions

Cited by 46 publications

References 51 publications

Multidimensional Investigation of Bedrock Heterogeneity/Unconformities at a DNAPL‐Impacted Site

Multidimensional Investigation of Bedrock Heterogeneity/Unconformities at a DNAPL‐Impacted Site

Characterization of a fluvial aquifer at a range of depths and scales: the Triassic St Bees Sandstone Formation, Cumbria, UK

Sedimentary flow heterogeneities in the Triassic U.K. Sherwood Sandstone Group: Insights for hydrocarbon exploration

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