Boulder Clay Research Articles

Ground investigation and design for a landfill at Seater, Caithness

Abstract This paper describes the site investigations and design considerations for a landfill development near Wick in Caithness, Scotland. The site is underlain by the Caithness Flagstone Series of the Middle Devonian with a thin cover of boulder clay and peaty topsoils. The location is on raised ground sloping gently to the north with poor natural drainage. The near-surface geology was investigated with a combination of ground-probing radar and trial pitting. Radar profiles from traverses across the site were correlated with the lithological information from the trial pits to provide an estimate of the thickness and nature of the superficial deposits. Groundwater and surface water conditions were investigated and a water balance calculated for design considerations. The final design allows for a 25-year landfilling facility operated on the containment principle. Perimeter, sub-level and internal drainage systems were incorporated in the design.

The genesis of the brown boulder clay of Dublin

Abstract This paper presents the results of a study into the physical, chemical and mineralogical composition of two glacial sediments in Dublin, Ireland which are colloquially called Dublin ‘brown’ and ‘black boulder clays’. The objective of this study was to ascertain whether the ‘brown’ was formed through weathering of the ‘black boulder clay‘ or whether it represents a depositional feature. The study included fabric, clast lithological and microscopic analyses as well as X-ray diffraction. This work has shown that the sedimentology and fabrics of both are of the same glacigenic origin and that the lithology and mineralogy are identical apart from oxidation of the clay particles in the ‘brown’. It is therefore concluded that the ‘brown boulder’ clay arises from the weathering processes affecting the upper levels of the ‘black boulder clay’. This finding is consistent with the differences in the geotechnical parameters.

Discussion on excavations at the Lower Palaeolithic site at East Farm, Barnham, Suffolk, 1989-1992

R. G. West & P. L. Gibbard write: The recent report 'Excavations at the Lower Palaeolithic site at East Farm, Barnham, Suffolk 1989-92' ( Ashton et al. 1994 a ) is welcome in providing initial results of a multi-disciplinary study of an important Lower Palaeolithic site, where local stratigraphy has provided a framework in which to place biostratigraphical and archaeological data. We wish, however, to discuss the question of dating of the temperate silts in the part of the paper entitled ‘Dating’. This relates temperate faunally-rich silt and clay at Barnham to Stage 11 of the global marine Quaternary stratigraphy based on Oxygen Isotope Stages (Shackleton & Opdyke 1973). The problem concerns the application of amino-acid analysis (AA) of mollusc shells, in particular D-alloisoleucine/L-isoleucine epimerization rates, to regionally established biostratigraphical and lithostratigraphical sequences. Amino-acid geochronology has made a major contribution to Quaternary stratigraphy, especially because it is a method which is applicable to freshwater and marine faunas, of age greater than those suitable for radiocarbon-dating. In the present case, there is a marked discrepancy between the present state of East Anglian regional stratigraphy (Table 1 and Ehlers et al. 1991 , table 41) and the correlation of the Barnham sediments with the global marine stratigraphy. The former says that the cold Anglian Stage, the latest part of which included the most widespread glaciation represented by Lowestoft Formation till (chalky boulder clay) in East Anglia, is succeeded by the temperate Hoxnian Stage. This stage is typified by the lacustrine sediments filling an enclosed depression in

A multiple till sequence near Ellon, Grampian Region: T. F. Jamieson’s ‘indigo boulder clay’ re-examined

Synopsis Jamieson in 1906 described an ‘indigo boulder clay’ lying beneath younger glacial deposits in the Ellon area, Grampian Region. A pitting survey has revealed that this unit (the Pitlurg Till) lies beneath Late Devensian glacial and glacifluvial deposits (the Hatton Till and the Kippet Hills Gravels and Sands) and rests on a basal till (the Bellscamphie Till). The Pitlurg Till contains palynomorphs of Kimmeridge Clay age and shows weak northerly fabrics, suggesting ice transport from the Moray Firth. Amino acid ratios for sparse included shells indicate that the Pitlurg Till is younger than Oxygen Isotope Stage 7 and may post-date Stage 5e. The Bellscaphie Till lies beneath weathered gravels at Tillybrex and probably predates Stage 5.

The iodine supply of humans depending on site, food offer and water supply

In Central Europe, the iodine content of weathered soils of new red sandstone, Muschelkalk, keuper and lower strata of new red sandstone, which developed from marine sediment is low. Boulder clays and diluvial sands also exhibit low iodine concentrations. In the same areas, the iodine concentration of drinking water decreases from 9 to 1 μg/l with increasing distance from the oceans. Cereals and foodstuffs produced from them are extremely iodine-poor. The iodine content of plants increases with the proportion of leaves. Soil contamination raises the iodine content of foodstuffs and improves the iodine supply of animals. The iodination of mineral mixtures increased the iodine content of cow's milk from 17 to 81 μg/l. The iodination of packed cooking salt and of the mineral mixtures for cattle and pigs resulted in a mean increase of the iodine intake of adults from about 30 μg/day to 48 and 59, respectively. Although iodine intake remained considerably below the calculated requirement for adults (100 to 150 μg/day), it led to the disappearance of Struma konnata and reduced the frequency of struma in children.

Effect of cultivation on physico—chemical, humus—chemical and biotic properties and fertility of two forest soils

A loamy Orthic Luvisol (Typic Hapludalf) and a sandy Haplic Podzol (Typic Haplorthod) under forest and agricultural cultivation were compared to assess the effects of cultivation on chemical and biotic properties and soil fertility. In the field, water, oxygen,thermal and nitrogen supply, soil respiration and cellulose degradation were determined during a 2 year period. In the laboratory soil organic matter (SOM) compounds, using a wet-chemical procedure, microbial biomass, enzyme activities and CO 2-release were determined in samples taken in autumn. In the arable Luvisol SOM turnover is limited by the lack of oxygen. A large mineral N-input enhances microbial activity in comparison with forest soil. This affects soil fertility and productivity. However, good environmental conditions for microorganisms are unecessary to obtain high yields. In spite of the high N-fertilization in the loamy soils derived from boulder clay there is little risk of groundwater pollution by nitrates. The Iron-Humus Podzol has been improved by agricultural management, which has increased pH, base saturation, SOM turnover and microbial activity. However, only 50% of the fertilizer is taken up by the crops and the remainder is leached or probably incororated into the SOM. In the sandur region characterized by sandy Podzols (1) large fertilizer nitrogen inputs nitrogen pollute the groundwater and (2) slurry fertilization of the arable soils also enhances the NH 4 + input into the forest soils. At present the nitrogen is fixed in solid organic matter and nitrate leaching in the forest soils is not important.

Photographic Feature The Scarborough Landslide

Early on Friday, 4 June 1993, a large portion of Scarborough's South Cliff collapsed into the sea. The length of the gardens of the Holbeck Hall Hotel, Scarborough's only four star accommodation, had been reduced drastically from 60m to a mere 15 m. The photograph shown in Fig. 1 was taken that morning by an RAF Air Sea Rescue helicopter. Cracks had begun to appear in the Hotel itself and the guests were evacuated during breakfast. Over the following three days, the cliff retreated another 35m, thereby undermining the hotel, which toppled over the cliff piece by piece whilst thousands of onlookers and the media watched in fascination. The police closed off the area to prevent the foolhardy and those interested in antiques from trying to climb the unstable mass. As the hotel gradually collapsed over several days, the national press in their search for new angles on the story, managed to draw parallels between the collapsing Hotel, the state of British sport and that of the Government. Residents of the houses behind the hotel wondered where the slip was going to stop and feared that the value of their properties would plummet. The ground behind the slip was monitored continually for signs of movement. The South Cliff consists mainly of glacial till (boulder clay), which overlies Middle Jurrassic rocks. In the cliff to the left of the landslide (Fig. 1), the Scalby Formation (part of the Upper Estuarine series of the Middle Jurassic Inferior Oolite) crops out and is

The application of geostatistical techniques to in situ resource estimation in the sand and gravel industry

Abstract In June 1990, a research project was commenced at a site in Southern England, in which sands and gravels of the Kesgrave Formation are overlain by Anglian boulder clay. This site was, at the time, under evaluation by RMC (UK) Ltd as a potential new source of natural aggregate. The primary aim of the research was to ascertain whether standard geostatistical techniques could be applied to Quaternary fluvio-glacial sand and gravel deposits. Comparisons would then be possible with the results of evaluations carried out using inverse distance weighting and digital terrain modelling techniques. The data used in the project were collected by shell and auger drilling on a localized detailed drilling grid (25 m spacing), and a less regular grid (100 m hole spacing) covering the whole site. The latter was carried out as part of a standard site evaluation. The variables used in the study included mineral and overburden thickness, size gradings as defined by BS:812, and petrography. The work has highlighted the need for improved methods of drilling and sampling in unconsolidated deposits. Loss of fine (<75 μm) material and poor sampling of the coarser (> 40 mm) fraction had resulted in excessively high nugget variances which caused difficulties in the modelling of semi-variograms for these size fractions. This paper presents the results of the geostatistical modelling of the above parameters using a range of methods including indicator variography and kriging. In particular, the deviation of the kriged block values from specific British Standards was assessed in order to determine the potential end use of the in situ material, before or after selective blending/processing.

The migration of uranium into peat-rich soils at Broubster, Caithness, Scotland, U.K.

Uranium is being actively transported from uraniferous sedimentary rocks into a peat bog at the Broubster natural analogue site in Caithness, Scotland. Massive calcareous sandstone within the Caithness Flags sequence is the main source of uranium which resides primarily within diagenetic apatite and dispersed USiTi phases. Supergene weathering processes have decalcified the sandstone and are effective in mobilising uranium by groundwater leaching, primarily along a fault zone. Uranium transport in solution by means of groundwater and surface flows is effectively terminated by retardation within 4-kyr-old peat deposits laid down on boulder clay. This process of secondary fixation has resulted in a young uranium anomaly in the peat which comprises in excess of 0.1 wt% U. The site has been investigated comprehensively to define the geometry of the anomaly together with the hydrogeology, hydrochemistry, petrology, mineralogy and the nature of the peat sink-term. The main physical and geochemical properties of the system, including the uranium decay series radionuclide distributions in water and solid samples, are documented in this paper. From these data, the processes governing the distribution of uranium have been quantified using a three-dimensional groundwater flow package and an equilibrium speciation model incorporating a recently developed electrostatic surface complexation model to account for cation-organic interactions. The results described form part of a coordinated project on natural radionuclide migration undertaken to improve confidence in predictive methods used for radiological assessment.

Quantification of the water balance and hydrogeological processes in the vicinity of a small groundwater-fed wetland, East Anglia, UK

Badley Moor Fen exists in a region of the UK where potential evapotranspiration exceeds annual rainfall. The wetland is maintained by an input of Chalk groundwater in an area where the groundwater aquifer is regionally confined below boulder clay. The large groundwater contribution to the water balance arises from a unique local geological situation on the margin of the valley floor that allows the vertical movement of groundwater to the surface under a strong upward head gradient. The groundwater contribution is the dominant water input and maintains saturation within the immediate vicinity of the source of groundwater. Surface water outflow, via adjacent drainage channels, is the major output. The groundwater component is also important in that, as a result of hydrochemical change in the groundwaters with flow towards the surface, tufa has been precipitated. The calcium bicarbonate rich groundwater and tufa accumulation have given the site a unique character, with an exceptionally rich calcareous fen community.

The influence of pre-Devensian glacial deposits on the hydrogeochemistry of the Chalk aquifer system of north Norfolk, UK

The distribution of hydrochemical facies in the Chalk aquifer system of north Norfolk, UK, is interpreted to reveal the hydraulic and hydrogeochemical processes operating in the area. The occurrence of two distinct glacial tills covering the Chalk aquifer is shown to dominate aquifer conditions. Chalk groundwater in the interfluve regions covered by Chalky Boulder Clay is characteristically of the order of 10 000 years old and compares with Chalk groundwater of about 1000–2000 years old in areas covered by North Sea Drift. The difference in age reflects the different mechanical compositions of the two glacial tills, with the Chalky Boulder Clay containing a higher clay content and lower sand content than the North Sea Drift. Hydrochemically, Chalk groundwater from beneath Chalky Boulder Clay is distinguished from groundwater associated with North Sea Drift by a HCO 3 concentration of 300 mgl −1, with higher values occurring beneath Chalky Boulder Clay. The reason for the difference is that recharge water entering the carbonatedepleted soils developed on North Sea Drift attains calcite saturation for low values of soil PCO 2 (in the range 10 −2.5–10 −2.0), whereas recharge entering carbonate-rich soils developed on Chalky Boulder Clay achieves calcite saturation for higher values of soil PCO 2 (in the range 10 −2.1–10 −2.0). Additionally, pyrite oxidation and SO 4 reduction associated with the Chalky Boulder Clay interfluve regions evolve further HCO 3 and, to maintain calcite equilibrium, increase the dissolved PCO 2 of the Chalk groundwater. In the interfluve regions, Mg, Sr and SiO 2 are able to increase because of the groundwater residence time which favours incongruent dissolution of the rock carbonate and breakdown of clay minerals contained in the glacial deposits and the Chalk. In contrast, modern valley zone Chalk groundwaters contain high concentrations of NO 3 (up to 120 mgl −1), SO 4 (up to 130 mgl −1) and Cl (up to 100 mgl −1) contributed by contamination, mainly from an agricultural source. The hydrochemical interpretation demonstrates that the varying glacial deposits are important in controlling recharge and groundwater flow within the Chalk aquifer. The Chalk aquifer in the interfluvial areas experiences minor recharge whereas the Chalk in the valley zone receives direct, modern recharge water. At the fluvial margin, glacial sands and gravels control the storage and release of water, transferred laterally through the glacial tills, to the high-transmissivity Chalk in the valley zone.

The Anglian—Hoxnian evolution of an ice-marginal drainage system in Suffolk, England

Deposits relating to the former Anglian ice-margin have been studied at two sites in southeast Suffolk: Rookery Farm, near Eyke; and at Shottisham. Their 3D geometry was established by a combination of ground conductivity mapping and augering/drilling. The deposits are predominantly clay-rich and commonly preserved in channels comparable with the ice-marginal channels described from adjacent parts of Suffolk. The early phase of sedimentation is characterized by till (boulder clay) and/or sand and gravel; subsequently lacustrine clay was deposited. These lacustrine clays are variably organic and were distinguished by their very high conductivity, enabling the thickest sequences to be pinpointed and drilled. Palynological investigation has shown that at both sites clays of mid-Hoxnian age are present. This indicates that the channelized Anglian ice-marginal drainage topography persisted until well into the succeeding warm Hoxnian Stage, with deposition of lacustrine clays commencing during a regional rise in water table in the mid-Hoxnian.

Late Quaternary stratigraphic signature, offshore from the Dutch barrier shoreline

More than 400 km of high-resolution, partially digitally acquired seismic data were collected in a 30 × 60 km area offshore from the Dutch mesotidal barrier island shoreline, in order to analyze the Holocene transgressive sequence. The investigated area was subaerially exposed during the most recent (Weichselian) Pleistocene lowstand and glaciated during the previous (Saale/Illinoian) glacial period. Sea level was probably at a level comparable to that of the present during the intervening Eem/Sangamonian highstand. The area's seismic signature is characterized by several levels of channelization, separated by major, area-wide high-amplitude reflectors. The lowermost aerial reflector represents the Saale boulder clay. The largest channel system, which cuts this reflector, was incised during the Older Dryas cooling event and filled during the Allerød warming period. It was subsequently re-incised during the Younger Dryas and refilled during the early Holocene. The most pronounced and extensive reflector represents the base of the Holocene, and almost everywhere equals the planed-off top of the Eem highstand section. This reflector is overlain by aggradational facies, separated by one level of channelization and one planed-off (ravinement?) surface. The most prominent type of seismic facies above the lowermost level of channelization is a set of progradational clinoforms, which is interpreted as a preserved ebb-tidal delta system. This system is associated with the first Holocene shoreline of ca. 7500 yrs BP. The eastern part of the study area contains sand ridges with a complex pattern of internal cross-stratification. Ridge-crest sediments are very well-sorted with a mean grain size of 2.8-2.6 φ (ca. 0.15 mm), whereas sediments in the troughs are well-sorted with a mean grain size of 1.8-0.8 φ (0.25–0.5 mm). Origin of these ridges is tentatively thought to be related to reworking since 5000 yrs BP, when the dynamic regime was more or less similar to that of the present and sediment supply had decreased substantially.

Modelling soil water dynamics in a forest ecosystem. II: Evaluation of spatial variation of soil profiles

AbstractThis paper is the second in a series of three papers, dealing with the hydrology of a forested lowland catchment, within the context of soil acidification research. the hydrological behaviour of the unsaturated soil zone is described with the numerical simulation model SWIF. the first paper presents a site specific model calibration and discusses the implications of the hydrological behaviour for soil acidification (Bouten et al., 1992). the present paper deals with the extension of the model results from one specific site to a larger research area. a third paper gives a model description and discusses its numerical behaviour (Tiktak and Bouten, 1992).In order to evaluate the effects of the field variability of soil horizon thicknesses, the model SWIF is validated by using measured groundwater table dynamics of three sites, each having different soil horizon thicknesses. Subsequently, a sensitivity analysis is carried out in order to select the location‐dependent model parameters that cause the main variation in hydrological behaviour. Finally, the spatial patterns of model results and of the location‐dependent model parameters are compared.The drainage depth and the depth of the boundary between the sandy top soil and the underlying boulder clay appear to be the key parameters that cause large differences in transpiration and in the vertical distribution of root water uptake and soil water fluxes. Spatial patterns of model results, therefore, also show resemblance with the spatial patterns of these location‐dependent model parameters.Simulation results for a reference location with averaged soil horizon thicknesses turn out to be beyond the 90 per cent confidence interval of the areal mean model results. This emphasizes the necessity to simulate first and then average.

The application of lime and cement soil stabilization at BAA airports

The Paper covers the introduction and progressive development of soil stabilization of the natural soil conditions at Gatwick, Stansted, Heathrow and Glasgow airports in the period 1980–1990. The main applications relate to the Weald Clay at Gatwick and the Boulder Clay at Stansted; reference is also made to work at Heathrow involving Gravel/Brickearth deposits and at Glasgow where soft clay deposits occur. The dual use of both lime and cement to modify and strengthen the natural subgrades and earthwork formation are described together with summaries of the main control testing results. Reference is also made to a general description of the specification and construction plant methods in use. The prime object of the Paper is to make available full practical details of large scale lime and cement soil stabilization work, bearing in mind the shortage of such information on construction site work undertaken in the UK.

Finite element analyses of an in situ wall propped at formation level

The use of formation-level props to support an in situ retaining wall can result in a structural system which is stiff and remote from rotational failure. However, the interaction between the wail, the soil and a continuous prop slab cannot be analysed using simple techniques. Finite element analyses have been carried out to investigate some of the factors affecting the behaviour of an in situ wall, propped at formation level, retaining 9 m of stiff overconsolidated boulder clay. This Paper describes the results of a parametric study in which the effects of soil/wall/prop stiffness and the pre-excavation earth pressure coefficient were investigated. It is found that, because the wall is very stiff, computed deformations are governed by the assumed stiffness of the soil rather than the flexura! rigidity of the wall. Bending moments in the wall are influenced significantly by the assumed pre-excavation lateral earth pressures and, to a lesser extent, by the nature of the structural connection between the wall and the permanent prop slab. L'emploi d'étais mis en place lors de la construction pour conforter un mur de soutènement en place peut produire un système structural rigide et peu sujet à la rupture circulaire. Il est cependant impossible d'analyser à l'aide de techniques simples l'interaction entre le mur, le sol et et une semelle d'appui continue. Des analyses a' éléments finis ont été effectuées pour étudier quelques-uns des facteurs qui influencent le comportement d'un mur en place étayé en cours de construction qui retient 9m d'argile à blocaux rigide surconsolidée. L'article décrit les résultats d'une étude paramétrique pour examiner les effets de la rigidité sol/mur/support et du coefficient de poussée des terres avant l'excavation. On a trouvé qu'en raison de la rigidité élevée du mur les déformations calculées sont regies par la rigidité admise du sol plutôt que par la rigidité en flexion du mur. Les moments de flexion dans le mur sont affectés de façon significative par les pressions latérales admises des terres avant l'excavation et aussi à un moindre degré par la nature du rapport structural entre le mur et la semelle d'appui permanente.

Rare temporary exposure of the Southern Upland Fault near Abington, Strathclyde

The Midland Valley of Scotland, long recognised as an ancient rift-valley structure, is bounded on both sides by major Caledonoid-trending faults which have a long history of repeated movemen t (Fig. la). The Southern Upland Fault (SUF) on its southeastern margin, though often expressed topographically as a good fault-scarp or valley feature, is usually blanketed by superficial deposits and the actual fault-plane is rarely seen. The authors therefore welcomed the opportunity to make a detailed examination of the Southern Upland Fault zone which was exposed briefly during earthmoving operations for the Millbank to Nether Abington phase of the new M74 currently under construction in Lanarkshire. The new road line runs u p to 1.5 km N E of the existing A74 and necessitated an 8 m cut into the boulder clay drape on the NE slope of Knock Leaven, some 4 km NW of Abington \[NS 911 266\] (Fig. 1b). Although the consultants (Kirkpatrick & Partners) had anticipated that the line of the new road would cross the SUF in this approximate location, it was not expected that the fault itself would be visible due to the depth of the overlying superficial deposits. It was only during final trim of the excavation on the northbound carriageway that the tell-tale traces of the fault were exposed, and careful excavation revealed an excellent planed-off section almost normal to the SUF (Figs. 2, 3, 4).

The structure of the cultivated horizon of a Stagnogleyic Luvisol developed from loam, within the zone affected by tractor wheel traffic

An analysis of the structure and physical properties was performed for a Stagnogleyic Luvisol developed from boulder clay and compacted by the front and rear wheels of a U-1212 tractor in the course of spring tillage. It was found that as a result of the compaction the structure of the soil was transformed from aggregated to non-aggregated. The rear wheel deformed the soil more strongly than the front wheel, the greatest compaction occurring in the soil mass pressed into the tyre tread grooves. Consequently, the greatest deterioration in the aeration properties of the soil was observed in that zone.

Physical and chemical properties of brown earths developed from boulder clay in Western Pomerania under arable farming, apple-tree orchard and deciduous forest, as affected by soil compaction

This paper presents the results of studies of changes in the physical and chemical properties of brown earths developed from light and medium silty loams as a consequence of different utilization. The effects of the soil utilization on its properties were determined by comparison of arable soil with adjacent forest soil (old deciduous forest) and with soil which was under apple-tree orchard for 35 years. Arable soils were more compacted than forest soils (total porosity 35.8–42.1 and 41.3–53.6%, v/v, respectively), had a lower non-capillary porosity and a worse structure. Chemical changes in these soils were not significant. Many years of orchard utilization worsened soil physical properties, especially at a depth of 15–45 cm in the grassed strips between tree rows and caused an increase in acidity and higher concentrations of zinc, copper and lead.

The geotechnical characteristics of the till deposits of Holderness

Abstract The glacial deposits of Holderness are well displayed along the coast of Humberside from Bridlington to Spurn Head. These deposits consist primarily of tills which may contain chalky debris and include pockets and lenses of sands and gravel. They have been subdivided in the past into four units the Basement, Drab, Purple and Hessle Boulder Clays. This has been re-interpreted as three tills (the Basement, Skipsea and Withernsea Tills) below a composite weathered unit of Skipsea and Withernsea Till. The dominant clay minerals in all the clays are kaolinite and illite. In addition, the clay fraction usually constitutes up to 30% of the deposit. Accordingly the clays have a low plasticity. However, because the Basement Till contains a larger content of fines it does have higher consistency limits. The geotechnical data confirm the interpretation of the “Hessle Clay” as a weathered product of the Skipsea and Withernsea Tills