Intracrystalline water adsorption of Ca-montmorillonite was calculated as the product of one-half the interlayer spacing from X-ray powder diffraction analysis and the difference between the desorption surface area determined with ethylene glycol-monoethyl ether and BET surface area determined by N2 adsorption. Osmotic adsorption was calculated as the product of the N2 surface area and theoretical double layer thickness. Measured water adsorption of P2O5-dry clay, compacted to initial densities (γ0) from 0.52 to 1.59 g/cm3 and submerged in 0.01 N CaCl2 was 2.4 to 4.2 times greater than intracrystalline plus osmotic adsorption due to the occurrence of pores exceeding double layer dimensions. The increase in expansion caused by reducing electrolyte concentration to 0.001 N was equal to the predicted increase in double layer volume, verifying the existence of an osmotic component to swelling.

Measured expansion following submersion in 0.01 N CaCl2 increased continuously with γ0 from 0.53 cm3/g at γ0 = 0.52 g/cm3 to 1.17 cm3/g at γ0 = 1.59 g/cm3, while estimated osmotic plus intracrystalline expansion was constant at 0.30 cm3/g. This discrepancy is attributed to swelling caused by gas pressures developing ahead of advancing wetting fronts. The effect of compaction on expansion is explained by reductions in pore size, as measured by N2 desorption, which accompany compaction. Reduced pore size should increase entrapped air pressures, whereas gradual wetting should favor their dissipation. Accordingly, slow wetting reduced the expansion of a sample where γ0 = 1.06 g/cm3 from 0.77 to 0.37 cm3/g. Swelling due to entrapped air pressures produced a large increase in the number of pores > 104 Å in diameter, as determined by Hg intrusion porosimetry.

Direct water-activity measurements were made for calcium-smectite-CaCl2 mixtures. The samples used were prepared by high-pressure filtration and had water contents <0.60% by weight of clay. For deionized water, the water activity (aw) ranged between 1 and 0.4 and was independent of the pressure history of the clay cake. Good agreement was found with the results of an adsorption isotherm. Samples were also prepared in 1,3, and 5 M CaCl2 solutions. The final concentration of chloride present in the cakes was measured: substantial anion exclusion was observed. The water activity of the clay-salt mixtures depended on both the water content and the concentration of CaCl2. The data can be well represented by the expression aw = min(aw0, aw*c × aw*s), where aw0 is the water activity of the brine used to prepare the cake, and aw*c and aw*s are water activities calculated for clay (in absence of salt) and salt (in absence of clay), respectively. The compaction and swelling behavior of a core of the same Ca-smectite was also investigated for pressures (P) between 0.5 and 800 bar. In two compaction-swelling cycles total recovery of the void ratio (e) was observed with, however, large hysteresis in the relationship between e and P. The osmotic pressure developed in the core at equilibrium, evaluated using the water-activity data, was intermediate between the compaction and swelling pressures. Apparently, another force, Pm, linked to irreversible changes in the structure of the matrix was contributing to the resistance to compaction. Pm values agreed with literature results for Ca-smectite suspensions.

We report on how the effects of mechanical compaction and clay mineral diagenesis have affected the alignment of phyllosilicates in a suite of Miocene-Pliocene mudstones buried to sub-seabed depths of between 1.8 and 5.8 km in the deep-water Gulf of Mexico. Mechanical compaction has reduced the porosity of the samples to 15% at 5 km, with modal pore sizes between 10 and 20 nm. High-resolution X-ray texture goniometry data show that the intense mechanical compaction has not resulted in a strongly aligned phyllosilicate fabric. The muds were apparently deposited with a weak or isotropic phyllosilicate fabric which was not substantially realigned by mechanical compaction. Unusually, X-ray diffraction of <0.2 µm separates shows that: (1) there is no illitization trend between 90 and 120°C; and (2) discrete smectite persists to ∼120°C, coexisting with R1 I-S or R0 I-S with 30–40% expandable layers. Between 120 and 130°C, discrete smectite disappears and the expandability of I-S decreases to ∼25–30%. We propose a two-stage diagenetic process involving (1) the alteration of volcanic glass to smectite and (2) the illitization of smectite and I-S; the alteration of glass results in smectite without a preferred orientation and retards the illitization reaction. We suggest that the lack of a strongly aligned phyllosilicate fabric reflects the apparently limited extent of illitization, and thus recrystallization, to which these mudstones have been subjected.

Collecting sea-level data from restricted coastal areas is essential for understanding local effects on relative sea level. Here, a revised relative mean sea-level curve for the area of the East Frisian island Langeoog, northwestern Germany, for the time period from 7200 cal BP until Recent is presented. The revision is based on the reinterpretation of previously published and unpublished data following the HOLSEA standardisation of data handling. Altogether 68 sea-level data taken from 32 cores and outcrops from Langeoog, its back-barrier and the adjacent mainland, which have been collected since the 1950s for mapping and landscape reconstruction purposes, are presented. The age constraints, derived from radiocarbon ages of basal peat, intercalated peat and molluscs and optical dating of tidal deposits, were evaluated in terms of the HOLSEA sea-level protocol and their stratigraphic context. For 7200 cal BP until modern times, 30 sea-level index points with different uncertainty ranges were defined. Additionally, a factor of decompaction was estimated for the remaining basal peat samples as well as for the underlying sediments of intercalated peat samples.

The comparison of the Langeoog relative sea-level curve with the relative sea-level curve from the western Netherlands shows that the Langeoog curve lies up to 0.80 m lower than the Dutch curve and diverges for the time before 6000 cal BP. Though the offset coincides with the overall predicted trend of glacial-isostatic adjustment, it is less than predicted.

Our study provides a useful assessment of legacy data and contributes to an improved sea-level index dataset for the southern North Sea coast.

Disposal of Finnish spent nuclear fuel is planned to be based on the KBS-3 repository concept. The role of the bentonite buffer in this concept is essential, and thus the behaviour of the bentonite has to be known. The experiments in this paper concentrated on providing information about the effects of carbon dioxide CO2(g) partial pressure on compacted sodium bentonite, giving an insight into the buffering capacity. The experimental setup consisted of a hermetic box which had a CO2-adjusted atmosphere, and the bentonite was in contact with this atmosphere through water reservoirs. The results indicated that it is possible to measure online the changing pH in the porewater inside compacted bentonite using IrOx electrodes. It was found that the pH fell if the CO2 partial pressure increased above atmospheric conditions. The experimental results indicated a greater fall in pH than in our model in the test cases where CO2 was present. The pH in the experiment with 0 PCO2 remained nearly constant throughout the 5 month period. On the other hand, the pH dropped to near 6 with 0.3 PCO2 and to 5.5 with 1 PCO2.

Bentonite mixed with varying quantities of sand is currently of widespread interest as engineering liners for water containment and waste disposal. However, the alternative use of pumice, widespread in many volcanic regions, has been less studied and requires further characterization of geotechnical properties and performance prior to its extensive use. The objective of this study was to determine and compare the compaction and swelling characteristics of sandbentonite and pumice-bentonite mixtures using available geo-materials from Turkey. Standard Proctor compaction tests and constant volume swell tests were carried out using mixtures with four different bentonite contents (15, 20, 25, 30%) and three different sand and pumice grain size ranges (2.00–1.00; 1.00–0.50; 0.50–0.25 mm). The results indicate that pumice-bentonite mixtures have lower maximum dry unit weights, higher optimum moisture contents and greater swelling potentials than equivalent sand-bentonite mixtures. Important differences occur in the swelling potentials of the sand and pumice mixtures with respect to grain size whereby sand-bentonite mixtures show increased swelling with coarsening grain size, in contrast to the pumice–bentonite mixtures which showed a decrease. These differences are attributed to the amount of grain-size-dependent connected pore space that can be filled during bentonite expansion and the presence of dissolvable salts in the pumice. It is concluded that locally available pumice material could be used to replace sand in engineering bentonite seals, despite some differences in their geotechnical properties.

In situ measurements were carried out to quantify montmorillonite dissolution rates at a compaction pressure ranging from 0.04 to 10.00 MPa and temperature of 70°C in 0.3 M NaOH solution (pH 12.1 at 70°C) using vertical scanning interferometry (VSI) and an auto-compaction cell. Ex situ measurements of the reacted samples using atomic force microscopy (AFM) were performed to quantify the ratio of edge surface area (ESA) to total surface area (TSA) (XESA = ESA/TSA). Accordingly, the actual ESA for the montmorillonite examined by in situ VSI could be estimated. The XESA value increases as a function of run duration or compaction pressure. At atmospheric pressure, XESA is approximately 0.0054 and converges to ∼0.0107 at 10 MPa, An expression that relates reactive surface area and montmorillonite compaction (XESA/XESA initial = kXESA, k: variable factor) is kXESA = 1.0 + 0.64628 P0.1527 where P is in MPa. Using the calculated XESA, dissolution rates from the in situ VSI measurements are obtained. The early dissolution (<1500 min) at less compaction pressure tends to show faster rates (>1.0 × 10-11 mol/m2/s) than that at higher compaction pressure. The rates after >1500 min are slower, with values of less than 3×6 10-12 mol/m2/s, but there is no significant dependency on the density in the range from 1.0 to 1.7 Mg/m3. These observed rates for compacted montmorillonite are two-orders of magnitude slower (2.63×10-13 mol/m2/s) than dissolution rates in the suspended state.

The ignimbrites of the northeast Niğde area, which are subdivided into the Lower, Middle and Upper ignimbrites on the basis of their compositional and stratigraphical characteristics, display textural variations from the base to the top. A large proportion of these ignimbrites have been altered and recrystallized by the processes of compaction, welding and devitrification, and as a result of volatile movement. The alteration and recrystallization processes include four stages: hydration, glassy and spherulitic stages accompanied by vapour-phase crystallisation. In the early phases of devitrification, detailed shard shapes are easily recognisable with the scanning electron microscope, but as alteration proceeds clarity of detail disappears because compaction results in collapse of the structure of the rock. Spherulitic and vapour-phase crystallisation usually involves the growth of alkali feldspar and cristobalite. These later stages are more common in the Upper Ignimbrite than the Middle and Lower ignimbrites.

Although investigation of the hydraulic conductivity behaviour of zeolite-bentonite mixtures (ZBMs) has been a topic of interest for researchers recently, the influence of compaction water content on the hydraulic conductivity of ZBMs has not been studied so far. This study discusses the hydraulic conductivities of ZBMs and compares the results with those of sand-bentonite mixtures (SBMs). The hydraulic conductivities of SBMs were unaffected by compaction water content and bentonite content, but the hydraulic conductivities of ZBMs were substantially different in mixtures containing 10% and 20% bentonite. The hydraulic conductivity of 10% ZBM (i.e. containing 10% bentonite and 90% wt. zeolite) gradually decreased as the water content increased to optimum water content and then it tended to decrease rapidly when the water content exceeded the optimum. In contrast, the hydraulic conductivity of 20% ZBM sharply decreased at the early stages of compaction water content (i.e. on the dry side of optimum water content) and levelled off when the water content was at the optimum water content. However, there is at least one order of magnitude difference between the hydraulic conductivities of ZBMs and SBMs, supporting the zeolite network model as suggested in previous works.

Not long after discovery of the Groningen field, gas-production-induced compaction and consequent land subsidence was recognised to be a potential threat to groundwater management in the province of Groningen, in addition to the fact that parts of the province lie below sea level. More recently, NAM's seismological model also pointed to a correlation between reservoir compaction and the observed induced seismicity above the field. In addition to the already existing requirement for accurate subsidence predictions, this demanded a more accurate description of the expected spatial and temporal development of compaction.

Since the start of production in 1963, multiple levelling campaigns have gathered a unique set of deformation measurements used to calibrate geomechanical models. In this paper we present a methodology to model compaction and subsidence, combining results from rock mechanics experiments and surface deformation measurements. Besides the optical spirit-levelling data, InSAR data are also used for inversion to compaction and calibration of compaction models. Residual analysis, i.e. analysis of the difference between measurement and model output, provides confidence in the model results used for subsidence forecasting and as input to seismological models.

Oceanic mangroves accumulate peat with sea-level rise without terrestrial sediment inputs, but fossil peat’s elevation as a tide-range limited sea-level indicator is assumed to be affected by compaction. Despite assumption of decomposition, compression, and dewatering, pure Rhizophora mangle peat appears coarse, water-saturated, and loose even at depth. Calibrated peat densities from computed tomography (CT) and petrologic analysis allow quantitative assessment of compaction in continuous peats from Florida (6 m thick), Belize (12 m thick), and Panama (3.5 m thick). Pure peat exhibits voids at all depths and >80% water contents. CT density does not increase with depth; bulk densities are low, minimally variable, and trend-free. Higher CT-density intervals coincide with compositional changes (sediment, coral). CT of peat buried under sediment shows a shift to higher densities. CT of air-dried continuous peat shows uncompressed fine and coarse roots and voids, with negative densities indicative of air in place of interstitial water. Peat’s high water content and hydraulic conductivity prevent dewatering and compaction, hypothetically maintaining original sea-level indicative elevations at intermediate depths. Non-compacted, sediment-free, offshore peats can provide a continuous proxy for reconstructing the record of sea-level rise at any site, if depositional, disturbance, and geochemical and biotic processes affecting 14C ages are also assessed.

The Groningen gas field has shown considerable compaction and subsidence since starting production in the early 1960s. The behaviour is understood from the geomechanical response of the reservoir pressure depletion. By integrating surface movement measurements and modelling, the model parameters can be constrained and understanding of the subsurface behaviour can be improved. Such a procedure has been employed to formulate new compaction and subsidence forecasts. The results are put into the context of an extensive review of the work performed in this field, both in Groningen and beyond. The review is used to formulate a way forward designed to integrate all knowledge in a stochastic manner.

Dynamical system theory is applied to the integrable nonlinear wave equation ut±(u3–u2)x+(u3)xxx=0. We obtain the single peak solitary wave solutions and compacton solutions of the equation. Regular compacton solution of the equation correspond to the case of wave speed c=0. In the case of c≠0, we find smooth soliton solutions. The influence of parameters of the traveling wave solutions is explored by using the phase portrait analytical technique. Asymptotic analysis and numerical simulations are provided for these soliton solutions of the nonlinear wave equation.

During its maximum extension, the Saalian ice cap reached into the central Netherlands, where glacier tongues excavated over 100 m deep basins in the unconsolidated Middle and Early Pleistocene sediments. The basins are filled by relatively thick successions of Late Saalian, Eemian and Weichselian sediments. The fill of the Amsterdam glacial basin is among the best known and studied in the Netherlands. The Late Saalian sediments consist mainly of warves and ill-bedded clays and silts with, along its southern margin, influxes of sands from the surrounding ice-pushed ridges. During deposition of these sediments, the Amsterdam basin formed part of a large lake extending into the present North Sea. Draining of this lake at the end of the Late Saalian left small, shallow pools at the site of the glacial basins.

Late Saalian and Eemian sediments are probably separated by a short break, although sedimentation may have been continuous in the deepest part of the basin. The Eemian deposits consist in main lines of a thin, diatom-rich sapropel at the base, overlain by an up to 30 m thick clay-rich sequence covered by a wedge of sand that measures more than 20 m in the northern part of the basin and that peters out southwards. As appears from the fauna, most of the clays were deposited in a lagoonal setting shielded behind a threshold and/or barrier. The rate of sediment supply was low so that lagoonal conditions were maintained over a long timespan. Sands derived from the surrounding ice-pushed ridges and transported by longshore drift and tidal currents formed a spit at the northern margin of the basin, which moved southward after eustatic sea-level rise stabilized and the lagoon was filled by clay. Loading of this clay-rich sequence by the spit and its washover fans induced subsidence, however, because of compaction, so that marine conditions were maintained until after the Eemian highstand. Fluvial and eolian sediments of Weichselian age, locally reaching a thickness of almost 10 m, eventually levelled the Amsterdam glacial basin.

The province of Groningen is flat and level, lying at an elevation close to sea level. The area is intensely cultivated and water table levels are a matter of concern. When the size of the Groningen gasfield was recognized in the sixties, it was realized, that substantial subsidence might occur at the surface affecting a large area.

Intensive studies were performed over time to predict future subsidence. These studies are supported by theoretical and experimental research in Shell since the 1950’s concerning reservoir compaction and related surface subsidence. To monitor reservoir compaction and surface subsidence on a regular basis, an extensive monitoring program was set up by NAM. The program comprises leveling surveys, GPS measurements, measurements of shallow formation compaction and in-situ reservoir compaction.

In Groningen weak earthquakes have occurred since 1991 at irregular intervals. A multidisciplinary study from 1991–1993 on the relationship between gas production and earthquakes in the northern part of the Netherlands, combined with further studies concluded, that under certain circumstances these earthquakes may result from gas production. Monitoring is carried out through a seismic observation network with borehole sensors and locally installed accelerometers.

Because of the expected impact of subsidence induced by gas production on surface water management, an Agreement was concluded between the Province of Groningen and NAM.

In line with the 1983 Agreement the ‘Commissie Bodemdaling’ was founded, in which both NAM and the Province of Groningen are represented. On the basis of NAM predictions and actual measurements this Committee determines, what measures are to be taken to prevent, minimize or to correct for effects of gas production induced surface subsidence.

Surface-soil structural condition in perennial pastures is expected to be modified by how forage is (a) harvested through haying or grazing and (b) stimulated through source of nutrients applied, as well as by compactive forces, e.g., grazing cattle or hay harvest machinery. Changes in surface-soil condition can affect hydrologic processes that have important implications for plant growth, greenhouse gas emissions and off-site water quality. We determined the effects of harvest management and nutrient source on the rate of ponded water infiltration and penetration resistance in a bermudagrass [Cynodon dactylon (L.) Pers.]/tall fescue (Lolium arundinaceum Schreb. S.J. Darbyshire) pasture on a Typic Kanhapludult in Georgia. During a period when soil was wet (61% water-filled pore space), the rate of water infiltration was 2.8 ± 1.5 times greater when forage was left unharvested as when hayed or grazed (mean ± standard deviation among nine nutrient source × harvest management comparisons). During a subsequent period, when soil was dry (28% water-filled pore space), the rate of water infiltration followed the same treatment pattern, but was not statistically different among harvest-management practices (1.5 ± 0.4 times greater between unharvested and other systems). Penetration resistance of the surface at 10 cm depth followed the order: unharvested (62 J) < hayed (100 J) < low grazing pressure (119 J) < high grazing pressure (137 J). Water infiltration during the wet period was negatively related (P ⩽ 0.01) to soil-water content (r = − 0.57), penetration resistance at 0–10 cm depth (r = − 0.50) and bulk density at 3–6 cm depth (r = − 0.53), but was positively related to surface residue C (r = 0.47) and soil organic C concentration at 12–20 cm depth (r = 0.42). These results suggest that complex soil physical (i.e., aggregation, penetration resistance and infiltration) and biological (i.e., plant growth, surface residues and soil organic matter) interactions occur in pastures. We conclude that well-managed grazing systems with excellent ground cover should have adequate hydrologic condition to promote pasture productivity and limit environmental contamination from runoff. Further work is needed to understand the linkages between field- and watershed-scale hydrology in perennial pastures and their implications on water quality.

The events resulting in compaction have an important influence on the processes related to blastocyst formation. To analyse the quality of the embryos obtained by somatic cell nuclear transfer (SCNT) in aspects different from previous studies, not only the number of blastomeres of cloned embryos during the initiation of compaction, but also the distribution of microvilli in cloned, normal, parthenogenetic, and tetraploid embryos before and after compaction was preliminarily investigated in mouse. Our results showed that during compaction the number of blastomeres in SCNT embryos was fewer than that in intracytoplasmic sperm injection (ICSI) embryos and, before compaction, there was a uniform distribution of microvilli over the blastomere surface, but microvilli became restricted to an apical region after compaction in the four types of embryos. We also reported here that the time course of compaction in SCNT embryos was about 3 h delayed compared with that in ICSI embryos, while there was no significant difference between SCNT and ICSI embryos when developed to the 4-cell stage. We concluded that: (i) the cleavage of blastomeres in cloned embryos was slow at least before compaction; (ii) the distribution of microvilli in cloned, normal, parthenogenetic, and tetraploid embryos was coherent before and after compaction; and (iii) the initiation of compaction in SCNT embryos was delayed compared with that of ICSI embryos.

We have examined immunocytochemically the subcellular distribution of the cell adhesion molecule uvomorulin in cleavage stage mouse embryos using conventional and confocal microscopy, under a range of detergent extraction and fixation regimes. Only traces of uvomorulin were detectable on the surface of unfertilised oocytes, whereas between 6 and 11 h after activation detergent-resistant surface expression was evident. This shift correlates with previously demonstrated changes in the pattern of synthesis and accumulation of uvomorulin from precursor state in unfertilised oocytes to mature protein after fertilisation. Embryos at subsequent stages up to the 8-cell stage exhibited a uniform distribution of uvomorulin on free surfaces and its concentration in regions of contact between blastomeres. At the 8-cell stage, during compaction, there was increased intercellular adhesion with concomitant accumulation of uvomorulin at intercellular contacts, whilst free surface uvomorulin was reduced and became relatively more susceptible to detergent extraction. When compact 8-cell embryos were decompacted in calcium-free medium, uvomorulin at contacts decreased while free surface and cytoplasmic staining increased. Blastomeres disaggregated from 4- and 8-cell embryos showed traces or ‘footprints’ of anti-uvomorulin staining in regions previously in apposition. These footprints disappeared over 45–60 min, during which time uvomorulin distribution became uniform. Possible mechanisms underlying the rearrangements which take place both at fertilisation and during compaction and experimental decompaction are discussed.

Staurosporine, an inhibitor of protein kinase activity, causes premature intercellular flattening of blastomeres but does not induce their premature polarisation. The flattening induced is calcium dependent, is reversed transiently at mitosis and requires the continuing presence of the drug. Staurosporine also blocks the decompacting effect of phorbol ester on 8-cell embryos.