scholarly journals First assessment of the pore water composition of Rupel Clay in the Netherlands and the characterisation of its reactive solids

2016 ◽  
Vol 95 (3) ◽  
pp. 315-335 ◽  
Author(s):  
Thilo Behrends ◽  
Iris van der Veen ◽  
Alwina Hoving ◽  
Jasper Griffioen
Keyword(s):  
The Netherlands ◽  
Pore Water ◽  
Solid Phase ◽  
Clay Material ◽  
Pore Waters ◽  
Calcium Carbonates ◽  
Boom Clay ◽  
Water Composition ◽  
Dilution Experiments ◽  
Chloride Concentrations

AbstractThe Rupel Clay member in the Netherlands largely corresponds to the Boom Formation in Belgium, and this marine, clay-rich deposit is a potential candidate to host radioactive waste disposal facilities. Prediction of the speciation of radionuclides in Rupel Clay pore water and their retardation by interactions with Rupel Clay components requires knowledge about the composition of Rupel Clay pore water, the inventory of reactive solids and understanding of interactions between Rupel Clay and pore water. Here, we studied Rupel Clay material which was obtained from cores collected in the province of Zeeland, the Netherlands, and from drilling cuttings retrieved from a drilling in the province of Limburg, the Netherlands. Pore water was obtained by mechanical squeezing of Rupel Clay material from Zeeland. Additionally, anaerobic dilution experiments were performed in which the clay material was suspended with demineralised water or a 0.1M NaHCO3solution. Solid-phase characterisation included determination of carbon, nitrogen and sulphur contents, measurement of cation exchange capacity (CEC) and sequential extraction of iron phases.In contrast to the pore water in Belgian Boom Clay, pore water collected from the location in Zeeland has a higher salinity, with chloride concentrations corresponding to 70–96% of those in seawater. The high chloride concentrations most likely result from the intrusion of ions from saline waters above the Rupel Clay in Zeeland. Cation exchange during salinisation might account for the observed deficit of marine cations (Na, K, Mg) and excess of Ca concentrations, in comparison with seawater. The measured CEC values at both locations in the Netherlands vary between 7 and 35 meq(100g)−1and are, for most samples, in the range reported for Boom Clay in Belgium (7–30meq(100g)−1).Pore water and solid-phase composition indicate that Rupel Clay from Zeeland has been affected by oxidation of pyrite or other Fe(II)-containing solids. When coupled to the dissolution of calcium carbonates, oxidation of pyrite can account for the elevated sulphate and calcium concentrations measured in some of the pore waters. The relatively low concentrations of pyrite, organic carbon and calcite in the Rupel Clay in Zeeland, in comparison to Limburg, might be an indicator for an oxidation event. Higher contents of dithionite-extractable Fe in Rupel Clay in Zeeland (0.7–2.6mg Fe / g clay) than in Limburg (0.4–0.5mg Fe / g clay) might also be a consequence of the oxidation of Fe(II) minerals. Oxidation in the past could have accompanied partial erosion of Rupel Clay in Zeeland before deposition of the Breda Formation. However, indications are given that oxidation occurred in some of the pore waters after sampling and that partial oxidation of the cores during storage cannot be excluded. Results from dilution experiments substantiate the influence of equilibration with calcium carbonates on pore water composition. Furthermore, removal of dissolved sulphate upon interaction with Rupel Clay has been observed in some dilution experiments, possibly involving microbial sulphate reduction.

Dissolution and recrystallization in modern shelf carbonates: evidence from pore water and solid phase chemistry

1993 ◽  
Vol 344 (1670) ◽  
pp. 27-36 ◽  
Keyword(s):  
Organic Matter ◽  
Pore Water ◽  
Solid Phase ◽  
Chemical Exchange ◽  
Isotope Composition ◽  
Geochemical Data ◽  
Carbonate Sediments ◽  
Pore Waters ◽  
Carbonate Minerals ◽  
Carbonate Production

We present an overview of geochemical data from pore waters and solid phases that clarify earliest diagenetic processes affecting modern, shallow marine carbonate sediments. Acids produced by organic matter decomposition react rapidly with metastable carbonate minerals in pore waters to produce extensive syndepositional dissolution and recrystallization. Stoichiometric relations among pore water solutes suggest that dissolution is related to oxidation of H 2 S which can accumulate in these low-Fe sediments. Sulphide oxidation likely occurs by enhanced diffusion of O 2 mediated by sulphide-oxidizing bacteria which colonize oxic/anoxic interfaces invaginating these intensely bioturbated sediments. Buffering of pore water stable isotopic compositions towards values of bulk sediment and rapid 45 Ca exchange rates during sediment incubations demonstrate that carbonate recrystallization is a significant process. Comparison of average biogenic carbonate production rates with estimated rates of dissolution and recrystallization suggests that over half the gross production is dissolved and/or recrystallized. Thus isotopic and elemental composition of carbonate minerals can experience significant alteration during earliest burial driven by chemical exchange among carbonate minerals and decomposing organic matter. Temporal shifts in palaeo-ocean carbon isotope composition inferred from bulk-rocks may be seriously compromised by facies-dependent differences in dissolution and recrystallization rates.

The Boom Clay geochemistry: Natural evidence

2006 ◽  
Vol 932 ◽  
Author(s):  
M. De Craen
Keyword(s):  
Pore Water ◽  
Point Of View ◽  
Water Sampling ◽  
Spent Fuel ◽  
Geochemical Composition ◽  
Boom Clay ◽  
Water Composition ◽  
Geological Processes ◽  
Long Time ◽  
High Level

ABSTRACTIn Belgium, the Boom Clay is studied as the reference formation for geological disposal of high-level radioactive waste and spent fuel. As the Boom Clay is considered as the main barrier for radionuclide migration/retention, a thorough characterisation of the clay and its pore water was done. This facilitates better understanding of the long-term geological processes and the distribution of the trace elements and radionuclides.From a mineralogical/geochemical point of view, the Boom Clay is considered as a rather homogeneous sediment, vertically as well as laterally. It is composed of detrital minerals, organic matter and fossils. Minerals are mainly clay minerals, quartz and feldspars. Minor amounts of pyrite and carbonates are also present. Small variations in mineralogical/geochemical composition are related to granulometrical variations. The radiochemical study indicates that the Boom Clay is in a state of secular radioactive equilibrium, meaning that the Boom Clay has not been disturbed for a very long time.Pore water sampling is done in situ from various piezometers, or by the squeezing or leaching of clay cores in the laboratory. These three pore water sampling techniques have been compared and evaluated. Boom Clay pore water is a NaHCO3 solution of 15 mM, containing 115 mg·1−1 of dissolved natural organic carbon. Some slight variations in pore water composition have been observed and can be explained by principles of chemical equilibrium.

scholarly journals Diagenetic Processes in Aquaculture Ponds Showing Metal Accumulation on Shrimp Gills

2021 ◽  
Vol 8 ◽  
Author(s):  
Hugues Lemonnier ◽  
Florence Royer ◽  
Florian Caradec ◽  
Etienne Lopez ◽  
Clarisse Hubert ◽  
...  
Keyword(s):  
Pore Water ◽  
Solid Phase ◽  
Acid Volatile Sulfide ◽  
Pore Waters ◽  
Dissolved Metals ◽  
Ecological Processes ◽  
Physico Chemical ◽  
Aquaculture Ponds ◽  
Tropical Aquaculture ◽  
Carbon Acid

The gill is the organ by which many toxic metals are taken up by crustaceans. Iron is known to precipitate at its surface, a phenomenon recently observed in some tropical aquaculture ponds. The present study uses a field approach to understand better the environmental conditions and ecological processes involved in this deposit. Because shrimp are exposed to reduced products originating from organic waste accumulated in the sediment, spatial variation in pH, redox potential and concentrations of dissolved metals in pore water were investigated in these ponds. Total organic carbon, acid volatile sulfide and pyrite were also analyzed in the solid phase. Fe2+ in pore waters showed high spatial variability between ponds and within the same pond with concentrations up to 1,193 μmol l–1. Behaviors of Fe2+, Mn2+ and Co2+ in pore water were similar. Four geochemical environments were identified, based on their physico-chemical characteristics. Highest concentrations for Fe2+, Mn2+ and Co2+ in sediment pore water occurred in slightly acidic and suboxic conditions. When the sediment became anoxic, the H2S produced reacted with Fe2+ and/or Co2+ to form acid volatile sulfide and pyrite. When pH increased, the concentration of free H2S rose up to 736 μmol l–1. With neutral and suboxic conditions, dissolved metal concentrations could be controlled by their precipitation as oxides and hydroxides. The production of pyrite suggested the existence of a possible process of sediment acidification between two crop periods through the production of sulfuric acid. This acidification could increase with pond age and be the cause of the accumulation of reduced metal after 30 years of aquaculture activity.

scholarly journals Palaeohydrogeology and Transport Parameters Derived from 4He and Cl Profiles in Aquitard Pore Waters in a Large Multilayer Aquifer System, Central Australia

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Stacey C. Priestley ◽  
Tavis Kleinig ◽  
Andrew J. Love ◽  
Vincent E. A. Post ◽  
Paul Shand ◽  
...  
Keyword(s):  
Solute Transport ◽  
Pore Water ◽  
Transport Model ◽  
Chloride Concentration ◽  
Pore Waters ◽  
Transport Parameters ◽  
Aquifer System ◽  
Water Composition ◽  
Central Australia ◽  
Upper Aquifer

A study of chloride and 4He profiles through an aquitard that separates the Great Artesian Basin from the underlying Arckaringa Basin in central Australia is presented. The aquitard separates two aquifers with long water residence times, due to low recharge rates in the arid climate. One-dimensional solute transport models were used to determine the advective flux of groundwater across the aquitard as well as establish any major changes in past hydrological conditions recorded by variations of the pore water composition. This in situ study showed that both diffusion and slow downward advection (vz=0.7 mm/yr) control solute transport. Numerical simulations show that an increase in chloride concentration in the upper part of the profile is due to a reduction in recharge in the upper aquifer for at least 3000 years. Groundwater extraction since 2008 has likely increased chloride and 4He concentrations in the lower aquifer by pulling up water from deeper layers; however, there has been insufficient time for upward solute transport into the pore water profile by diffusion against downward advection. The transport model of 4He and chloride provides insight into how the two aquifers interact through the aquitard and how climate change is being recorded in the aquitard profile.

Determination of Interstitial Chloride in Shales and Consolidated Rocks by a Precision Leaching Technique

1985 ◽  
Vol 25 (05) ◽  
pp. 704-710
Author(s):  
F.T. Manheim ◽  
E.E. Peck ◽  
C.M. Lane
Keyword(s):  
Pore Water ◽  
Interstitial Water ◽  
Bound Water ◽  
Chloride Content ◽  
Pore Fluid ◽  
Distilled Water ◽  
Water Composition ◽  
Deep Earth ◽  
Chloride Concentrations

Abstract We have devised a technique for determining chloride in interstitial water of consolidated rocks. Samples of rocks ranging from 5 to 10 g are crushed and sieved under controlled conditions and then ground with distilled water to submicron size in a closed mechanical mill. After ultra-centrifugation, chloride content is determined by coulometric titration. The chloride concentrations and total pore-water concentrations, obtained earlier from the same pore-water concentrations, obtained earlier from the same samples by low-temperature vacuum desiccation, are used to arrive at the "original" pore-water chloride concentrations by a simple iteration procedure. Interstitial chlorinity results obtained from Cretaceous and Jurassic strata in the Gulf of Mexico coastal areas ranged from 20 to 100 g/kg Cl with reproducibility approaching +/- 1%. We have also applied the technique to igneous and metamorphic bedrocks as well as ocean basalts containing 1 % water or less. Chloride values ranging from 6.7 to 20 g/kg with a reproducibility of about 5% were obtained. Introduction This paper outlines a technique for precision analysis of interstitial chloride and water content (porosity) of shales and other consolidated rocks from deep-earth strata. Nearly all the literature on the composition of interstitial water (formation fluid) of deep-earth strata refers to fluids from reservoir rocks or permeable horizons. In many areas, shales or other nonreservoir rocks constitute the bulk of sedimentary sequences. These rocks contain interstitial fluids of generally unknown composition. The paucity of data is caused partly by the lack of access to fresh cores and partly by analytical difficulties in obtaining interstitial water from such materials. Until the late 1960's, much of the analytical literature dealing with pore fluids from deep sedimentary nonreservoir rocks was published in the Soviet Union and in references cited by those authors. Since then, interest in several hydrochemical phenomena relating to nonreservoir rocks has increased among phenomena relating to nonreservoir rocks has increased among scientists in the U.S. and other Western countries: interest in hydrocarbon resources in overpressured strata dominated by undercompacted shales that may have anomalous chloride content; need for knowledge of the proportion of bound water (electrolyte-poor) in porosity proportion of bound water (electrolyte-poor) in porosity during quantitative interpretation of electrical logs for oil and gas saturation in shaly sands; need for better understanding of nonreservoir rocks as sealing beds for deep waste disposal; and, finally, a desire to understand better the hydrochemical history of deeper sedimentary basins. However, only a relatively few field studies are available on the topics in question. Many of these are student theses or work based on them. The basic procedure underlying the studies of interstitial water composition of shales is simply crushing and grinding a rock sample, leaching it with distilled water, and analyzing the leachate. The salt content of the solid is then related to an independent determination of total pore fluid or porosity. Techniques based on this principle were used for shallow groundwater studies, for general rocks, and for studying oilfield drill cores. Comments in the literature and our own experiments suggest that simple approaches to the leaching process may yield accuracies of 10 to 20% for chlorides in rocks with a significant PV fraction. As water contents decrease to 1%, however, an uncontrolled system may easily yield errors of several hundred percent and uncertainties associated with the bound water (see the section called Discussion). Most of the studies of interstitial chlorinity of water composition in deep oilfield strata have been performed on stored, dried, or partly dried materials and/or have used insufficiently documented or quantified techniques. The goal of this study has been to approach a reproducibility and relative accuracy of I % in the values of interstitial chloride, given our definition of mobile water discussed later. Sampling and Handling of Drilling-Core Samples A potential source of error in interstitial fluid analysis is the contamination of cores by drilling fluid. However, experience in the Deep Sea Drilling Project and other drilling studies 11–15 show that, if external contaminated layers are cut or chipped away from undeformed normal, non-fractured silty-clay cores soon after recovery, virtually unaffected inner sections can be obtained. Even permeable (reservoir-type) rocks sometimes may be sampled successfully for pore-fluid study. During wireline coring by the AMCOR project with the drilling vessel Glomar Conception on the Atlantic Continental Shelf, virtually identical pore-fluid chloride profiles were obtained in repeated drillings performed with seawater and freshwater drilling fluids (Fig. 1). SPEJ P. 704

Early diagenetic processes in Labrador Sea sediments: uranium-isotope geochemistry

1994 ◽  
Vol 31 (1) ◽  
pp. 28-37 ◽  
Author(s):  
C. Gariépy ◽  
B. Ghaleb ◽  
C. Hillaire-Marcel ◽  
A. Mucci ◽  
S. Vallières
Keyword(s):  
Isotopic Composition ◽  
Pore Water ◽  
Iron Reduction ◽  
Molecular Diffusion ◽  
Solid Phase ◽  
Redox Conditions ◽  
Labrador Sea ◽  
Benthic Boundary Layer ◽  
Ionization Mass ◽  
Pore Waters

The concentration and isotopic composition of U dissolved in pore waters from hemipelagic sediments of the Labrador Sea were determined by thermal ionization mass spectrometry in two 30 cm long box cores. The present fluxes of seawater U that diffuses across the sediment–seawater interface are on the order of 2–4 μg/(cm2∙ka). This diffusion imposes decreasing gradients of dissolved U downwards, but the U concentration in pore waters immediately below the surface is much lower than that of open-ocean seawater. This is a primary feature that cannot be explained by carbonate precipitation due to decompression during core retrieval. More likely, it reflects the presence of a stagnant benthic boundary layer above the sediment–water interface, in which molecular diffusion of U is slower than in the overlying turbulently mixed seawater, and (or) of microzones near the interface where U is bioaccumulated. Uranium is adsorbed at depths onto the solid phase in response to changes in the redox conditions within the sediments. In the Labrador Sea, this occurs at the onset of iron reduction and corresponds to a colour transition from brown to grey. Adsorption of U is sufficiently large to alter the initial content and the isotopic composition of U in the detrital component. Accumulation of authigenic U on the solid phase does not proceed at a steady state. This is due to the uneven burial rates of organic matter, which is essential to the establishment of redox conditions appropriate for U reduction, and concomitant stepwise displacement of the redox fronts. This indicates that discrete periods of enhanced primary productivity recurred over the last millenium in the Labrador Sea, inducing U fluxes to the sediments greater than they are now. Measured pore-water U concentrations are greater than the overlying seawater at depth in the cores, despite the fact that none of the conditions necessary to release U under reducing conditions are present in the sediments. More likely, U-bearing particles < 0.45 μm were transferred with the solution phase through the filtering device, artificially increasing the pore-water U content.

In Situ Measurements of Pore Water Diffusion Coefficients Using Tritiated Water

1980 ◽  
Vol 37 (3) ◽  
pp. 545-551 ◽  
Author(s):  
R. H. Hesslein
Keyword(s):  
Pore Water ◽  
Diffusion Coefficients ◽  
Molecular Diffusion ◽  
Solid Phase ◽  
Tritiated Water ◽  
Water Diffusion ◽  
Pore Waters ◽  
Sediment Depth ◽  
Constant Diffusivity

In situ diffusion coefficients in the pore waters of Lake 227 were measured by monitoring the movement of tritiated water into the pore waters. The diffusion coefficients were determined by analytical and numerical modeling of the tritium profiles. During the summer, tritiated water diffuses into the sediment by molecular diffusion and this process is well approximated by a constant diffusivity model. The summer coefficients for diffusion were 1–2 × 10−5 cm2∙s−1 at a water depth of 1.5 m (20 °C) and 0.3–0.8 × 10−6 cm2∙s−1 at 8.75 m (4 °C). During fall overturn, clear evidence was found for enhanced mixing of pore waters to a sediment depth of 10 cm at water depths of 0.75 and 3.85 m. This enhanced mixing was not accompanied by mixing of the solid phase of the sediments.Key words: sediments, pore water, diffusion coefficients, tritium, lake sediments

scholarly journals Hydrochemistry of sediment pore water in the Bratsk reservoir (Baikal region, Russia)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
V. I. Poletaeva ◽  
E. N. Tirskikh ◽  
M. V. Pastukhov
Keyword(s):  
Pore Water ◽  
Ionic Composition ◽  
Water System ◽  
Water Reservoir ◽  
Environmental Parameters ◽  
Water Area ◽  
Pore Waters ◽  
Overlying Water ◽  
Major Ion ◽  
Bratsk Reservoir

AbstractThis study aimed to identify the factors responsible for the major ion composition of pore water from the bottom sediments of the Bratsk water reservoir, which is part of the largest freshwater Baikal-Angara water system. In the Bratsk reservoir, the overlying water was characterized as HCO3–Ca–Mg type with the mineralization ranging between 101.2 and 127.7 mg L−1 and pore water was characterized as HCO3–SO4–Ca, SO4–Cl–Ca–Mg and mixed water types, which had mineralization varying from 165.9 to 4608.1 mg L−1. The ionic composition of pore waters varied both along the sediment depth profile and across the water area. In pore water, the difference between the highest and lowest values was remarkably large: 5.1 times for K+, 13 times for Mg2+, 16 times for HCO3−, 20 times for Ca2+, 23 times for Na+, 80 times for SO42−, 105 times for Cl−. Such variability at different sites of the reservoir was due to the interrelation between major ion concentrations in the pore water and environmental parameters. The major factor responsible for pore water chemistry was the dissolution of sediment-forming material coming from various geochemical provinces. In the south part of the reservoir, Cl−, Na+ and SO42− concentrations may significantly increase in pore water due to the effect of subaqueous flow of highly mineralized groundwater.

scholarly journals Spatial variation in porosity and permeability of the Rupel Clay Member in the Netherlands

2016 ◽  
Vol 95 (3) ◽  
pp. 253-268 ◽  
Author(s):  
Hanneke Verweij ◽  
Geert-Jan Vis ◽  
Elke Imberechts
Keyword(s):  
The Netherlands ◽  
Spatial Variation ◽  
Clay Content ◽  
Burial Depth ◽  
Southeastern Part ◽  
Boom Clay ◽  
The North ◽  
Sealing Capacity ◽  
Porosity And Permeability ◽  
Permeability Data

AbstractThe spatial distribution of porosity and permeability of the Rupel Clay Member is of key importance to evaluate the spatial variation of its sealing capacity and groundwater flow condition. There are only a limited number of measured porosity and permeability data of the Rupel Clay Member in the onshore Netherlands and these data are restricted to shallow depths in the order of tens of metres below surface. Grain sizes measured by laser diffraction and SediGraph® in samples of the Rupel Clay Member taken from boreholes spread across the country were used to generate new porosity and permeability data for the Rupel Clay Member located at greater burial depth. Effective stress and clay content are important parameters in the applied grain-size based calculations of porosity and permeability.The calculation method was first tested on measured data of the Belgian Boom Clay. The test results showed good agreement between calculated permeability and measured hydraulic conductivity for depths exceeding 200m.The spatial variation in lithology, heterogeneity and also burial depth of the Rupel Clay Member in the Netherlands are apparent in the variation of the calculated permeability. The samples from the north of the country consist almost entirely of muds and as a consequence show little lithology-related variation in permeability. The vertical variation in permeability in the more heterogeneous Rupel Clay Member in the southern and east-southeastern part of the country can reach several orders of magnitude due to increased permeability of the coarser-grained layers.

Pore water composition of volcanogenic sediments from across the Central American Subduction Zone

2009 ◽  
Vol 101 (1) ◽  
pp. 88
Author(s):  
Ulrike Schacht ◽  
Steffen Kutterolf ◽  
Oliver Bartdorff ◽  
Emelina Corrales Cordero
Keyword(s):  
Subduction Zone ◽  
Pore Water ◽  
Central American ◽  
Water Composition ◽  
Central American Subduction Zone
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