Infiltration Experiments Research Articles

Фильтрационные исследования влияния забойного давления на фазовую проницаемость для нефти и вязкость нефти при частичном разгазировании

Фильтрационные исследования влияния забойного давления на фазовую проницаемость для нефти и вязкость нефти при частичном разгазировании

Capillary Barrier Effect in an Earthen Roof of Historical House

A capillary barrier is a widely used drainage system in recent years. It has been in practice since the end of the 1950s, and research over the past 60 years has provided valuable insight into its safe and economical design. Although capillary barrier application is not an old and traditional technique, it is possible to see its primitive application on earthen roofs of traditional buildings. One of these applications is in the earthen roofs of historical and protected houses in Kemaliye district in eastern Turkey. In this study, the capillary barrier behaviour of the earthen roof system of historical Kemaliye houses, which has existed for centuries, has been experimentally investigated. In this context, soil index properties and water characteristic curves were determined by conducting laboratory experiments on samples taken from the soil roof of a traditional Kemaliye house. In order to examine the capillary barrier behaviour of the roof in precipitation, 1D model infiltration experiments were carried out. In the light of the findings obtained from these experiments, it was concluded that the earthen roofs of traditional Kemaliye houses show varied capillary barrier behaviour depending on the initial conditions of the layers.

Investigating the effect of soil cracks on preferential flow using a dye tracing infiltration experiment in karst in Southwest China

AbstractSoil cracks significantly affect the preferential flow, and various uncertainties are associated with the effect of soil cracks on preferential flow in karst areas in Southwest China. This study investigated soil crack properties (inclusions, width, and configuration) by applying ground‐penetrating RADAR (GPR) to pedons. Blue dye‐tracing experiments were designed based on the geophysical detection results to assess the influences of crack inclusions (sand grains and rock fragments), crack widths (1, 1.5, and 2 cm), and configurations (I‐shape, V‐shape, and Λ‐shape) on preferential flow. The following results were obtained: (1) the GPR envelope can describe the configuration of isolated soil cracks; (2) soil cracks can accelerate infiltration and increase the maximum dye‐penetration depth, cumulative infiltration, and wetting‐front depth by averages of at least 5.2%, 63.2% and 4.4%, respectively; and (3) the I‐ and Λ‐shaped soil crack configurations contributed to preferential flow, but the preferential flow was not observed along the V‐shaped‐configuration‐crack pore paths despite the retardation of brilliant blue FCF. The I‐shaped configurations, with a crack width of 1.5 cm, were filled with rock fragments and had higher preferential flow ratios (18.2%–52.3%) and length indices (4.0%–33.8%) compared to the other configurations. In summary, inclusions, crack width, and configuration significantly influence the preferential flow (p < 0.05), and the influence of these soil crack properties on preferential flow cannot be neglected during vegetation restoration and groundwater security operations in karst areas.

Seasonal and Soil Use Dependent Variability of Physical and Hydraulic Properties: An Assessment under Minimum Tillage and No-Tillage in a Long-Term Experiment in Southern Italy

Defining the optimal sampling time across the growing season is crucial to standardize sampling protocols for soil physical status monitoring and to achieve comparable results under different experimental conditions and on different sites. In this study, the seasonal variability of soil physical and hydraulic properties under two conservative soil management strategies, minimum tillage and no-tillage, was evaluated in a long-term field experiment. On two sampling dates, autumn 2021 and summer 2022, soil bulk density (BD) and volumetric soil water content at the time of the experiments (θi) were measured in each experimental unit and Beerkan infiltration experiments were performed. The soil water retention curve and the hydraulic conductivity function were then estimated using the Beerkan estimation of soil transfer parameters (BEST) methodology. In this way, the saturated hydraulic conductivity (Ks) and a set of capacitive indicators—plant available water capacity (PAWC), soil macroporosity (PMAC), air capacity (AC) and relative field capacity (RFC)—were obtained. Results underlined the role of soil moisture conditions as a main factor affecting variability in soil physical properties. Different soil moisture under autumn and summer samplings significantly affected BD (1.0093 and 1.1905 g cm−3, respectively, in autumn and summer) and Ks (0.0431 and 0.0492 mm s−1). Relationships observed between BEST-derived variables, such as PMAC (or AC) and RFC, and measured variables, such as BD, showed consistent results, with increases in PMAC to BD decreases. However, a comparison of capacity-based indicators obtained by BEST with those obtained from measured soil water retention curves, in a previous year but under comparable soil conditions, highlighted some discrepancies. This finding drives the focus towards the need to use more robust datasets deriving from experimental measurements or from coupling information obtained from measured and estimated data. Finally, this study provided further evidence that, in the long-term field experiment investigated, the two soil management systems allowed keeping the values of key soil physical quality indicators, such as bulk density and saturated hydraulic conductivity, within the optimal or near- optimal reference ranges.

Subsurface mobility of land applied greenhouse nutrient feed water and environmental implications

Greenhouse nutrient feedwater (GNF) discharge is considered a potential contributor to eutrophication issues in Lake Erie, Ontario. Land application of GNF is an accepted legislated management response to mitigate the impact of such nutrient loads. To assess the potential environmental impacts of this management practice, field infiltration experiments were conducted at four different greenhouse operations near Leamington, Ontario. Over a three-year study, GNF was applied on agricultural land adjacent to the greenhouse operations in the fall during the first year, and along with a bromide tracer in the summer and fall in Years 2 and 3, respectively. The GNF was applied at the maximum allowable rates as defined in legislation. Chemical constituents (nutrients, metals and the conservative tracer bromide) were monitored within the soil profile matrix and pore water above the water table. The results showed that, even with the GNF being applied at the highest permissible rates, the species of interest remained within the unsaturated soil zone at low concentrations over three to six months sampling intervals. The bromide tracer test demonstrated that highly mobile species could move through permeable soils to the water table depth in a potential worst-case application scenario. However, considering the low initial concentrations, long vadose zone residence time and the low mass flux, it would appear that land application of GNF, when applied in accordance with Ontario's Regulations, is a feasible and environmentally reasonable treatment option for managing GNF.

Brackish water promote the ecological restoration of estuarine wetland

By taking the indoor soil column experiment as the experimental simulation object, an infiltration experiment was conducted using freshwater and brackish water with different concentrations (3-g/L, 9-g/L). The constant head or air boundary of 3 cm was set as different variables (Where the air boundary means the water surface is flush with the soil interface, and the 3 cm fixed head boundary means the water accumulation depth is 3 cm above the soil interface). By analyzing the cumulative infiltration, soil water content, wetting peak, and infiltration rate, the effects of different water and salt conditions and different boundary conditions on the infiltration process were summarized and analyzed. The results show that the infiltration rate was most favorable under the 3-g/L brackish water infiltration. Under this condition, the cumulative infiltration was the largest, the time for the soil moisture content to reach saturation was the shortest, the wetting peak first reached the bottom of the soil column, and the soil water potential changed first. The constant head condition accelerated the infiltration rate of soil water, increased the cumulative infiltration, increased the soil water content, and reduced the time for the wetting peak to reach the bottom. Compared with that in the air boundary condition, the soil water potential under the constant head infiltration condition was larger. These experimental results show that to some extent, proper concentrations of saltwater are conducive to the infiltration and circulation of soil water. The demand for water saving in agricultural irrigation is increasing, and the efficiency of agricultural irrigation can be improved by making full use of the theory of unsaturated soil infiltration. The instability and complexity of unsaturated soil is due to the presence of matrix suction, so the study of unsaturated soil has profound theoretical significance.

Study on Water Vertical Infiltration Characteristics and Water Content Simulation of Sandstone Overlying Loess

Research on the infiltration characteristics of surface water is fundamental for understanding the entire hydrological process. Therefore, studying the water infiltration process of sandstone slopes overlaid with loess and predicting soil moisture content are of great importance for investigating hydrological processes and controlling soil erosion in the hilly and gully areas of the Loess Plateau in China. This study mainly focuses on the simulation of the vertical water infiltration characteristics and water movement patterns of four kinds of sandstone (feldspathic and argillaceous sandstone) structures covered with thin layers of loess. In the one-dimensional vertical infiltration experiment and Hydrus-1D model simulation, the interlayer transition planes of loess–feldspathic and loess–feldspathic–argillaceous sandstones were found to present two conditions: fine soil covering coarse soil and coarse soil covering fine soil. Therefore, water infiltration reduced permeability. The existence of a transition layer between loess and feldspathic sandstone decreased the water infiltration rate and infiltration amount and decelerated the speed of the wetting front, thereby further affecting the ability of water infiltration. By using the Hydrus-1D model, 15 sets of soil hydraulic parameters, including θx (0.028–0.05795 cm3/cm3), θs (0.2306–0.4786 cm3/cm3), α (0.01899–0.06071 cm−1), n (1.438–6.408), and Ks (1.96·10−4–0.0576 cm/s) were inverted and optimized for each 20 cm soil layer (total of 60 cm). The Van Genuchten model constructed using these parameters demonstrated high accuracy in the simulation of water content in the vertical infiltration process of sandstone covered by loess with the coefficient of determination R2 > 0.849 and relative error RE < 5.311.

Local Stability in the Process of Excavation Located in High Permeability Saturated Sand of Diaphragm Wall Construction

The stability of the slurry trench is very important in the construction of the underground diaphragm wall. In the current research, the local instability of the slurry trench is mainly investigated after the excavation of a unit slot is completely completed. However, the local stability in the process of excavation has received little attention. In this paper, the local stability in the process of excavation located in high permeability strata of diaphragm wall construction is investigated. A slurry infiltration experiment was carried out to investigate the distribution of the excess pore pressure in the high permeability strata, which can determine the effective support pressure. Then, the local stability of the slurry trench in the process of excavation located in high permeability saturated sand is calculated. The results show that the same types of sand according to the design code cannot be simply treated to have the same permeability and similar distribution of the excess pore pressure, since whether the filter cake can be formed and the quality of the filter cake are the key factors to determine the distribution of the excess pore pressure. This is also crucial for the local stability in the process of excavation located in high permeability saturated sand. It is suggested that attention should be paid to the local stability in the process of excavation located in high permeability strata when the slurry infiltration mode is the pure permeable zone.

The Effects of Long-Acting Water Erosion on the Hydro-Pedological Characteristics of Chernozems

In sloped and intensively managed land, the soil characteristics are influenced mainly by water erosion intensity. In the present study, we evaluate the characteristics of Chernozems damaged by long-acting water erosion, particularly their retention and infiltration properties and possible impacts on soil fertility. Using infiltration experiments and a collection of intact samples, we performed analyses of the physical soil properties in individual transects. Our results confirm the lower infiltration capacity of deteriorated soil in the accumulation slope parts, which corresponded with the analyses of soil samples. The reduced bulk density in the accumulation slope parts exceeded 1.5 g·cm−3, indicating unsatisfactory (non-structured) soil conditions. In the transportation and eluvial slope zones, porosity values reached satisfactory numbers only at a depth of 10 cm. The median values of aeration showed a similar trend, but we recorded a higher value fluctuation.

The Effect of Molten Salt Infiltration on 2D SiCf/SiC Composite by Chemical Vapour Infiltration.

The SiCf/SiC composite manufactured by chemical vapour infiltration (CVI) is a kind of porous material. Liquid molten salt in a Molten Salt Reactor (MSR) may enter into the porous composites and affect their performance. Through the study of the internal pores in the material, the permeability behaviour of the material can be investigated, which is of great significance to the analysis of the properties of the material itself. However, there is less investigation on effects of molten salt infiltration on the internal pore structure of SiCf/SiC composites. In this paper, a molten salt infiltration experiment of 2D woven SiCf/SiC composites was implemented at 650 °C, 3 atm. SEM, CT and XRD were used to characterize it. The results indicated that the microstructure could be affected by partial molten salt infiltration and temperature change. The distribution of porosity of the composite showed an obvious transformation. The lattice spacing of SiC showed an increased tendancy of stress relaxation.

In situ estimation of soil hydraulic and hydrodispersive properties by inversion of electromagnetic induction measurements and soil hydrological modeling

Abstract. Soil hydraulic and hydrodispersive properties are necessary for modeling water and solute fluxes in agricultural and environmental systems. Despite the major efforts in developing methods (e.g., laboratory-based, pedotransfer functions), their characterization at applicative scales remains an imperative requirement. Accordingly, this paper proposes a noninvasive in situ method integrating electromagnetic induction (EMI) and hydrological modeling to estimate soil hydraulic and transport properties at the plot scale. To this end, we carried out two sequential water infiltration and solute transport experiments and conducted time-lapse EMI surveys using a CMD Mini-Explorer to examine how well this methodology can be used to (i) monitor water content dynamic after irrigation and to estimate the soil hydraulic van Genuchten–Mualem parameters from the water infiltration experiment as well as (ii) to monitor solute concentration and to estimate solute dispersivity from the solute transport experiment. We then compared the results with those estimated by direct time domain reflectometry (TDR) and tensiometer probe measurements. The EMI significantly underestimated the water content distribution observed by TDR, but the water content evolved similarly over time. This introduced two main effects on soil hydraulic properties obtained by the two methods: (i) similar water retention curve shapes, but underestimated saturated water content from the EMI method, resulting in a scaled water retention curve when compared with the TDR method; the EMI-based water retention curve can be scaled by measuring the actual saturated water content at the end of the experiment with TDR probes or by weighing soil samples; (ii) almost overlapping hydraulic conductivity curves, as expected when considering that the shape of the hydraulic conductivity curve primarily reflects changes in water content over time. Nevertheless, EMI-based estimations of soil hydraulic properties and transport properties were found to be fairly accurate in comparison with those obtained from direct TDR measurements and tensiometer probe measurements.

Automated calibration methodology to avoid convergence issues during inverse identification of soil hydraulic properties

Inverse modeling of in-situ experiments is already a standardized approach for identifying various types of material parameters. In this contribution we are focused on the single ring (hereafter SR) infiltration experiment, which is a standard and robust dynamic field experiment. The steady state part of this experiment is traditionally used for the identification of saturated hydraulic conductivity. We explore here the possibility of extending the applicability of this experiment for evaluating the hydraulic parameters for unsaturated conditions from an unsteady part of this experiment for the top soil layer using inverse analyses of the governing flow motion equation. The problem of SR infiltration is governed by the quasilinear Richards equation. We present a new scanning methodology to avoid convergence issues with the nonlinear operator, originating from difficult combinations of input parameters, which can be hard to avoid when automatically analyzing a broad parameter space. We validated our methodology with virtual infiltration problems for clay and sand, and applied it on real-world SR infiltration data. To evaluate non-uniqueness, local optima were identified and mapped using a modified genetic algorithm with niching.Our results show the existence of multimodality in, both, the benchmark problems and the real-world problem. This is an important finding as local optima can be identified, which are not necessarily physical and also for systems that do not exhibit multimodal grain size distributions. The identified local optima were distinct and showed different retention and hydraulic conductivity curves. The most physical set of SHP could be identified with the knowledge of the saturated water content.

Towards the influences of three types of biocrusts on soil water in drylands: Insights from horizontal infiltration and soil water retention

As a “living skin” of soil in drylands, biocrusts possibly change the retention and movement of soil water, and thus critically influence hydrological and erosion processes as well as soil moisture regime. Contrary to vertical infiltration, little attention was paid to horizontal infiltration, which may provide important information on soil water diffusivity and sorptivity. In this study, the one-dimensional horizontal infiltration experiments for bare soil and three types of biocrusts (cyanobacterial, cyanobacterial-moss mixed, and moss crusts) were conducted with disturbed soil samples in a semiarid dryland. Undisturbed soil samples were also taken for each treatment, and their soil water retention capacity were determined in the laboratory. The substantial differences that were found were analyzed, and the differences were further validated through monitoring and comparing their in situ soil moisture regimes at depth of 0–20 cm. Our results showed that the three types of biocrusts had significantly lower constant infiltration rate (0.11 vs. 0.18 cm min−1) and infiltration water amount (6.75 vs. 10.01 cm) than bare soil, and their wetting front moved much slower (0.60 vs. 1.14 cm min−1) in comparison to bare soil, with bare soil > cyanobacterial crusts > cyanobacterial-moss mixed crusts > moss crusts. Total sorptivity of cyanobacterial, mixed, and moss crusts were 21%, 32%, and 53% lower than that of bare soil, respectively. More importantly, at the same level of water content, all crust types had lower water diffusivity, sorptivity, and conductivity than the bare soil, and exhibited a higher water content than bare soil at a same level of matric potential (across the range of −15,000–0 hPa), indicating an increase in water-holding capacity and water availability of the biocrusts in contrast to bare soil. Furthermore, the in-situ soil water content of all biocrusts increased on average by 30% at depth of 0–10 cm but decreased by 23% at 10–20 cm. Confirming the lower infiltrability and higher water-holding capacity of the biocrusts in comparison to bare soil, biocrusts increase surface soil water retention capacity and water availability at the surface, thus playing a vital role in reshaping the surface soil water balance, which subsequently may affect surface hydropedological and biochemical processes in drylands.

Evaluating Spatial-Temporal Clogging Evolution in a Meso-Scale Lysimeter

When surface water infiltrates soil, the fine soil particles carried in water gradually clog soil pores and form a low-permeability soil layer. Clogging impacts the variations in pore water pressure heads in soil and effective hydraulic conductivity. However, few studies have connected field measurements of pore water pressure heads to clogging in soil. This study proposed a diagram to demonstrate the relationship between the normalized pore water pressure head (λ) and effective hydraulic conductivity (Keff) based on a conceptual 1-D vertical infiltration model. The coevolution of λ and Keff indicated the occurrence of clogging and its location relative to the pore-pressure measurement point. We validated the λ-Keff diagram based on a series of numerical simulations of infiltration experiments in a lysimeter. The simulation results showed that the proposed diagram not only indicated the occurrence of clogging but also the development of the unsaturated zone beneath the upper clogging layer. Furthermore, we used a diagram to analyze the spatiotemporal changes in permeability in a lysimeter during three cycles of physical infiltration experiments. The experimental data presented with λ-Keff diagram indicated cracking on the soil surface, and clogging gradually developed at the bottom of the lysimeter.

Visualization study on preferential flow in highly saturated and super hydrophilic porous media by combining dye tracking and infrared imaging

• New method to track finger flow in highly saturated superhydrophilic porous media. • Preferential flow recurrence was observed at high saturation. • The preferential flow was found to impair desalination efficiency. • The temperature distribution was controlled by preferential flow. Air-gap diffusion distillation (AGDD) is a practical desalination technique. The highly saturated super hydrophilic porous medium as its evaporation surface has a decisive influence on the desalination efficiency of AGDD. In experiments, we found preferential flow in porous media. However, the preferential flow in highly saturated super hydrophilic porous media has not been studied, and the effect of preferential paths on evaporation from porous media surfaces remains poorly understood. The method of combining dye tracking and infrared imaging was used to visualize the process of thermal seepage in highly saturated super hydrophilic porous media. Under the condition of uniform and continuous liquid supply on the upper surface, the preferential flow characteristics of hot stream seepage in porous media are tracked; Point source infiltration experiments were carried out at room temperature to compare the difference between preferential flow in super hydrophilic porous media and general soil (sand). The experimental results of thermal seepage showed that the preferential flow greatly influences the uneven temperature distribution of the porous media, which directly impairs the desalination efficiency of AGDD. According to the coefficient of variation (CV), the preferential flow development process can be divided into three stages: stable development, exponential development, and high-speed growth. As the seepage flow is stabilized, the influence of preferential flow on the flow field and temperature field still exists and is affected by these three stages. Preferential flow characteristics were also captured in the saturated capillary rise zone at the bottom of the porous medium (below the phreatic level). The point source infiltration experiment found that the preferential flow in superhydrophilic porous medium will reappear at high saturation, which is completely different from the soil (sand) studied by previous studies. In addition, the effects of inlet temperature, flow rate, thickness, and hydrophilic, hygroscopicity on preferential flow were discussed. Increasing the flow rate and inlet temperature and reducing the thickness of the porous media can weaken the influence of preferential flow on the temperature field. But increasing the temperature only superficially weakens the preferential flow. Increasing hydrophilicity and hygroscopicity can also reduce the preferential flow.

Effects of Microtopography on Runoff Generation in Plain Farmland: New Insights from an Event-Based Rainfall–Runoff Model

Plain farmland areas without significant topographic slope exhibit microtopographic features of different scales. Quantitative assessment of the effects of microtopography at different scales on runoff generation in typical farmland areas is of great significance for regional water resources management and flood disaster forecasting. The main objective of the study was to develop an event-based rainfall–runoff model based on the layered Green–Ampt model (LGAM) with the consideration of plot-scale microtopographic features in plain farmland areas. Our experimental field, located in Taihu Lake Basin, was classified into three types of topographic subunits (i.e., main field, rill, and ditch) according to the average elevation. To simplify the concentration process for three topographic subunits, the average concentration time method was employed. Here, various experimental scenarios were simulated, including two classical unsteady rainfall events in homogeneous soil, one ponding infiltration experiment, and two typical rainfall–runoff events in the experimental field. We found that the multilayered setting showed higher accuracy than the homogeneous setting for simulating infiltration in the ponding infiltration experiment in the field. The RMSE of simulated ponding water depth reduced from 0.166 cm to 0.035 cm and NSE rose from 0.988 to 0.999. The simulated hydrograph considering microtopography effects proved higher accuracy than that under unified topography assumption. After classifying topography, the RMSE and NSE of simulated hydrographs decreased and increased, respectively. The lower the topographic subunit, the earlier the outflow occurred. At the early stage, the runoff mostly originated from the relatively low topographic subunits. Infiltration-excess regime under saturated condition may initially dominate in the low-lying ditch under intense rainfall, with extremely high runoff coefficient. Concentration process in the plain farmland area was affected by both rainfall intensity and microtopography. The greater the rainfall intensity, the shorter the average concentration time. The concentration velocity under heavy rainfall was four times faster than that under light rainfall. The lower topographic subunit was characterized by shorter concentration pathway and average concentration time. Ditches reduced the peak flow and advanced the time to peak. This quantitative study provides new insights into effects of microtopography on runoff generation in plain farmland area as well as an effective alternative for plot-scale rainfall–runoff modeling.

Experimental study of wetting effect of surfactant based on dynamic wetting process and impedance response of coal.

Surfactant can improve the wettability of water to coal, which is beneficial to reduce the production of coal dust in coal seam water injection. Through the measurement and calculation of contact angle and its decay rate, the wettability differences of SDS (C12H25OSO3Na), AES (C14H29O5NaS), OP-10 (C18H30O10), and JFC (RO(CH2CH2O)nH) to anthracite were compared. In addition, the wetting modification effect and infiltration rate of anthracite by water, AES, and OP-10 were studied by infrared spectroscopy and complex impedance monitoring of coal pillar immersion process. The results show that when the concentration of surfactant is 0.1%, the contact angle decay time of OP-10 is very short, and the contact angle decay rate is as high as 19°/s. The decay rate can more obviously reflect the wettability difference of surfactants. And the wetting modification effect of OP-10 on anthracite is stronger than that of AES, and the peaks of oxygen-containing functional groups such as carboxyl and hydroxyl groups are stronger. Furthermore, the capillary force between OP-10 and anthracite is much larger than that of water, which shows the characteristics of fast water absorption and wide distribution in the infiltration experiment of columnar coal. The results of complex impedance measurement indicate that the impedance decay rate of coal is well correlated with capillary rise factor FC, contact angle decay rate, and contact angle. It is hoped that the research results can provide help for coal seam water injection and dust prevention.

Effect of the Water-Air Coupling on the Stability of Rainfall-Induced Landslides Using a Coupled Infiltration and Hydromechanical Model

The water and air flow in soil pores in response to rainfall infiltration is an important factor affecting the stability of rainfall-induced landslides. The objective of this paper is to investigate the effect of water-air flow on the deformation and stability of rainfall-induced landslides based on a coupled infiltration and hydromechanical model. The model is formulated by the water and air flow equation, the mechanical equilibrium, and porosity equations. The rainfall infiltration is introduced as a flux boundary, which is determined according to the comparison of the infiltration capacity and rainfall intensity. The numerical model and solution approach are validated by simulating the Liakopoulos drainage test and a rainfall infiltration experiment with satisfactory results. Taking the Tanjiawan landslide as a case study, the water and air flow in response to rainfall infiltration and its effect on deformation and stability are examined. The results show that the pore air is gradually trapped and compressed due to rainwater infiltration. The entrapped air has a slowing effect on the rainfall infiltration and a pushing-out effect on the front sliding body, which is an important driving force for the evolution of the slope deformation and stability due to rainfall infiltration.

Vein and Wehrlite Formation in the Lithospheric Mantle Below the West Eifel Volcanic Field: Modelling the Effects of Pressure, Temperature and Peridotite/Melt Ratio on Magma-Peridotite Interaction Using pMELTS and a Melt Infiltration Experiment

Abstract The mantle peridotite xenoliths of the West Eifel Volcanic Field in Germany preserve evidence of multiple phases of metasomatism. The most recent metasomatic episode produced a variety of veins in the peridotite: high temperature (>1150°C), phlogopite–clinopyroxenite intermediate temperature (~1150°C), olivine clinopyroxenite and relatively low temperature (<1100°C) hornblendite together with marginal reaction zones of wehrlite and dunite. The veins and associated reaction zones have been interpreted as products of crystallization of magmas similar to those that transported the xenoliths to surface. We describe a high temperature melt infiltration experiment and thermodynamic (pMELTS) models that examine the origin of high temperature phlogopite–clinopyroxenite veins and the evolution of the wall rock adjacent to the veins and compare the result to the major and trace element signatures of the minerals in the veins. The infiltration experiment replicates the common reaction textures such as partially dissolved orthopyroxene and sieved secondary clinopyroxene that are found associated with veins. In the thermodynamic model, we calculated the equilibrium assemblages and mineral compositions for peridotite–melt mixtures ranging from peridotite only to melt only over the range of 1150 to 1350°C and 1 GPa to 2 GPa. The models reproduce the composition of vein minerals at a small peridotite/melt ratio, whereas at larger peridotite/melt ratios they produce wehrlite/dunite assemblages that are similar both in modal mineralogy and composition to the natural samples. The models show that olivine clinopyroxenite veins may have been produced at a higher pressure than the phlogopite–clinopyroxenite veins. Our models show that interaction of magma with a trace element signature indicative of a garnet-bearing source with spinel facies mantle will result in a dilution of the trace element garnet signature with little to no variation in the major oxide composition.

Transfer of trace organic compounds in an operational soil-aquifer treatment system assessed through an intrinsic tracer test and transport modelling.

Soil Aquifer Treatment (SAT) can provide supplementary treatment of trace organic compounds (TrOCs) such as pharmaceutical and industrial compounds present in Secondary Treated Wastewater (STWW). Concern on presence of unregulated TrOCs in natural systems has raised recently as well as the interest in SAT systems for remediation. The present study quantifies, at the field scale over35 m of lateral groundwater flow, the effectiveness of the Agon-Coutainville SAT system (Manche, Normandy, France) for TrOCs removal by sorption and biodegradation through monitoring of seven TrOCs (oxazepam, carbamazepine, benzotriazole, tolyltriazole, caffein, paracetamol, ibuprofen) and major inorganic compounds as intrinsic tracers in STWW and groundwater during a 34-day STWW infiltration experiment during operational use of the SAT. Cationic exchanges and mixing between groundwater and STWW during the experiment were highlighted by major ions and geochemical simulations. Due to the low thickness of the unsaturated zone, a 1D analytical solution of the advection-dispersion equation (ADE) was applied on chloride data. Chloride was used as conservative intrinsic tracer to calibrate the horizontal flow and transport parameters such as the aquifer dispersion coefficient (D) and the average pore water velocity (ν) allowing estimation of the groundwater residence time. Transport and attenuation of the TrOCs were simulated assuming first-order degradation constant (μ) and linear retardation coefficient (R), calibrated to simulate the observed temporal changes in the breakthrough of TrOCs. Sorption was found to play a role in the transport of TrOCs, notably for oxazepam with a higher linear retardation coefficient value of 2.2, whereas no significant differences of retardation were observed for carbamazepine, tolyltriazole, benzotriazole (1.37, 1.35, 1.36 respectively). Estimated first order degradation rate constants, between 0.03d-1 for carbamazepine and 0.09d-1 for tolyltriazole, were generally high compared to the literature, possibly due to favourable redox conditions and important microbial activities within the system. This study provides evidence of the efficiency of the Agon-Coutainville SAT system for the removal of TrOCs.