Characterizing the hydrogeology of a complex clay-rich aquitard system using detailed vertical profiles of the stable isotopes of water

Hendry, M. Jim; Kelln, Chris J.; Wassenaar, Leonard I.; Shaw, J.

doi:10.1016/j.jhydrol.2004.01.010

Cited by 50 publications

(12 citation statements)

References 37 publications

(53 reference statements)

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“…In general, physical extraction methods are laborious and have the potential for evaporative isotopic fractionation caused by storage, multistep procedures, or by incomplete recovery of the water or evaporative loss during handling. Alternative methods for obtaining pore water isotopes from cores include radial diffusion mass-balance mixing cells (Altinier et al, 2007;Bensenouci et al, 2013;Rubel et al, 2002;Savoye et al, 2006;van der Kamp et al, 1996) or direct equilibration of the pore water in core sub-samples using helium-CO 2 or a He-H 2 catalyst mixtures with headspace gas-water equilibration (Hendry et al, 2004;Kelln et al, 2007;Koehler et al, 2000). Wassenaar et al (2008) proposed a novel method for measuring the δ 2 H and δ 18 O of pore water in saturated and unsaturated geologic (core, soil) samples by using a direct vapour equilibration and laser spectrometry (DVE-LS) approach.…”

Section: Published By Copernicus Publications On Behalf Of the Europementioning

confidence: 99%

Determining the stable isotope composition of pore water from saturated and unsaturated zone core: improvements to the direct vapour equilibration laser spectrometry method

Hendry

Schmeling

Wassenaar

et al. 2015

Hydrol. Earth Syst. Sci.

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Abstract.A method to measure the δ 2 H and δ 18 O composition of pore waters in saturated and unsaturated geologic core samples using direct vapour equilibration and laser spectrometry (DVE-LS) was first described in 2008, and has since been rapidly adopted. Here, we describe a number of important methodological improvements and limitations encountered in routine application of DVE-LS over several years. Generally, good comparative agreement, as well as accuracy, is obtained between core pore water isotopic data obtained using DVE-LS and that measured on water squeezed from the same core. In complex hydrogeologic settings, high-resolution DVE-LS depth profiles provide greater spatial resolution of isotopic profiles compared to long-screened or nested piezometers. When fluid is used during drilling and coring (e.g. water rotary or wet sonic drill methods), spiking the drill fluid with 2 H can be conducted to identify core contamination. DVE-LS analyses yield accurate formational isotopic data for fine-textured core (e.g. clay, shale) samples, but are less effective for cores obtained from saturated permeable (e.g. sand, gravels) geologic media or on chip samples that are easily contaminated by wet rotary drilling fluid. Data obtained from DVE-LS analyses of core samples collected using wet (contamination by drill water) and dry sonic (water loss by heating) methods were also problematic. Accurate DVE-LS results can be obtained on core samples with gravimetric water contents > 5 % by increasing the sample size tested. Inexpensive Ziploc ™ gassampling bags were determined to be as good as, if not better than, other, more expensive specialty bags. Sample storage in sample bags provides acceptable results for up to 10 days of storage; however, measurable water loss, as well as evaporitic isotopic enrichment, occurs for samples stored for up to 6 months. With appropriate care taken during sample collection and storage, the DVE-LS approach for obtaining high-resolution pore water isotopic data is a promising alternative to study the hydrogeology of saturated and unsaturated sediments. Eliminating analytical interferences from volatile organics remains a challenge.

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Section: Published By Copernicus Publications On Behalf Of the Europementioning

confidence: 99%

Determining the stable isotope composition of pore water from saturated and unsaturated zone core: improvements to the direct vapour equilibration laser spectrometry method

Hendry

Schmeling

Wassenaar

et al. 2015

Hydrol. Earth Syst. Sci.

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show abstract

“…The δ 2 H and δ 18 O have frequently been used to identify the source of groundwater (Desaulniers et al ., ; Remenda et al ., ; Hendry and Wassenaar, ; Clark et al ., ; Husain et al ., ; Hendry and Woodbury, ; Hendry et al ., , ). Researchers also used δ 2 H and δ 18 O depth profiles to characterize the hydrogeology and hydraulic properties of aquitard systems (Remenda et al ., ; Hendry et al ., ; Hendry and Wassenaar, ; Hendry et al ., ). Recent studies show that sedimentation may also have a significant effect on the evolution of δ 2 H and δ 18 O depth profiles in sediment under seawater (Paul et al ., ; Schrag et al ., ).…”

Section: Introductionmentioning

confidence: 99%

Numerical studies of vertical Cl⁻, δ²H and δ¹⁸O profiles in the aquifer-aquitard system in the Pearl River Delta, China

2015

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Abstract:Sedimentation may have a significant effect on the transport of solutes and environmental isotopes in sediment. The depth profiles of the Cl À , δ 2 H and δ 18 O in a borehole in the aquifer-aquitard system in the Pearl River Delta (PRD), China, were obtained by centrifuging the core sediment samples. A one-dimensional model based on the sedimentation and sea level changes of the PRD during the Holocene was built to investigate numerically the transport mechanisms of Cl À , δ 2 H and δ 18O. The sedimentation process was modelled as a moving boundary problem with the moving rate equal to the sedimentation rate. The model was calibrated and the parameters were obtained by comparing simulated and measured data. Very good agreement between all the three observed profiles and the simulated ones demonstrates the reliability of the model and the parameters. Simulation results show that the shapes of the curves are controlled by the combination of sedimentation and upper boundary conditions. Diffusion solely is adequate to reconstruct the observed profiles, which indicates that diffusion is the dominant vertical transport mechanism. The effective diffusion coefficients of the aquitard and the aquifer equal to 5.0 × 10 À11 and 2.0 × 10 À10 m 2 /s, respectively. The results of this study will help in understanding the transport mechanisms of solutes and environmental tracers in deltas with geology and hydrogeology similar to the PRD.

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“…0.5 m). The hydrogeology of clay tills is often difficult to characterize due to the potential presence of fractures and/or sand lenses, which can create a complex network of preferential flow paths through the clay till [Gerber et al, 2001;Hendry et al, 2004;Kessler et al, 2013]. Migration of DNAPL into clay tills is only possible if the till is fractured [O'Hara et al, 2000].…”

Section: Conceptual Representations Of the Clay Tillmentioning

confidence: 99%

“…Clay tills are common in northern Europe and parts of North America [Christiansen et al, 2008;Parker et al, 2008] and can lead to a complex system of preferential flow paths (e.g. fractures or sand lenses) in a low permeability matrix [Damgaard et al, 2013a;Damgaard et al, 2013b;Gerber et al, 2001;Hendry et al, 2004;Kessler et al, 2012;Kessler et al, 2013]. Capturing a correct conceptual understanding of such sites is crucial in risk assessment and management where predictions of contaminant breakthrough, leaching time and remedial options are required.…”

Section: Introductionmentioning

confidence: 99%

A Bayesian belief network approach for assessing uncertainty in conceptual site models at contaminated sites

Thomsen¹,

Binning²,

McKnight³

et al. 2016

Journal of Contaminant Hydrology

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Characterizing the hydrogeology of a complex clay-rich aquitard system using detailed vertical profiles of the stable isotopes of water

Cited by 50 publications

References 37 publications

Determining the stable isotope composition of pore water from saturated and unsaturated zone core: improvements to the direct vapour equilibration laser spectrometry method

Determining the stable isotope composition of pore water from saturated and unsaturated zone core: improvements to the direct vapour equilibration laser spectrometry method

Numerical studies of vertical Cl⁻, δ²H and δ¹⁸O profiles in the aquifer-aquitard system in the Pearl River Delta, China

A Bayesian belief network approach for assessing uncertainty in conceptual site models at contaminated sites

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Characterizing the hydrogeology of a complex clay-rich aquitard system using detailed vertical profiles of the stable isotopes of water

Cited by 50 publications

References 37 publications

Determining the stable isotope composition of pore water from saturated and unsaturated zone core: improvements to the direct vapour equilibration laser spectrometry method

Determining the stable isotope composition of pore water from saturated and unsaturated zone core: improvements to the direct vapour equilibration laser spectrometry method

Numerical studies of vertical Cl−, δ2H and δ18O profiles in the aquifer-aquitard system in the Pearl River Delta, China

A Bayesian belief network approach for assessing uncertainty in conceptual site models at contaminated sites

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Numerical studies of vertical Cl⁻, δ²H and δ¹⁸O profiles in the aquifer-aquitard system in the Pearl River Delta, China