Geomorphological, geophysical, archaeological and documentary investigations have been employed to establish the variation of sea level change, sediment supply and geological control from the Late-Holocene, through the Historical period to the Present day, in Sanday. Techniques such as Ground-Penetrating Radar and geomorphological Radar and geomorphological surveying have identified a suite of gravel ridge recurves and placed them within their geomorphological context. The provisional regional sea level curve has been updated and clarified following the discovery and successful dating of a submerged forest. This sea level curve was then used to constrain the development of the coast of Sanday into separate time period. A range of archaeological and historical evidence also informed and corroborated the geomorphological evidence to allow the island’s coastal development to be established over the last few thousand years towards the present day, where differential-GPS and sonar techniques allowed these long-term trends to be placed into their modern context. Island-building occurred during Holocene submergence along with other radical changes to the shape and form of the coastline, all reflecting the changing dominance between the three controlling factors. The accepted outcome of submergence is transgression and fragmentation of islands rather than island building and this is wholly a result of a healthy sediment supply at the early stages. However, this sediment source has since begun to diminish and fragmentation, erosion and transgression may well be the outcome of the present trends in Sanday. This coastal change scenario has been projected forward, using climate change scenarios, to raise significant questions not only for Sanday and those regions which have historically experienced submergence, but also for those areas which previously experienced emergence and more recently are starting to be affected by relative sea level rise

Sellafield in West Cumbria is the potential site of a repository for radioactive, Intermediate Level Waste (ILW). The proposed repository lies at 650 m beneath the ground surface to the west of the 1000 m uplands of the Lake District. The fractured Borrowdale Volcanic Group (BVG) host rock is overlain by a sequence of Carboniferous and Permo-Triassic sediments. Fresh, saline and brine groundwaters exist in the subsurface. Upward trending fluid pressure gradients have been measured in the area of the potential repository site. Steady-state, 2-D simulations of fluid flow were undertaken with the OILGEN code. Topographically driven flow dominates the regional hydrogeology. Subsurface fluid flow trended persistently upwards through the potential repository site. The dense brines to the west of the site promoted upward deflection of groundwaters. The groundwater flow rate through the potential repository site was dependent upon the hydraulic conductivity of the BVG. Calibration of the model was achieved by matching simulated subsurface pressures to those measured in-situ. Emergent repository fluids could reach the surface in 15,000 years. The measured BVG hydraulic conductivity is up to 1000 times too high to be simply declared safe. Geochemical simulations, with Geochemist's Workbench?, showed natural BVG groundwaters display redox disequilibrium. The in-situ Eh is most probably +66 mV. Pyrite, absent from rock fractures, would not enforce a reducing -250 mV Eh. Steel barrels and alkaline cement are intended to geochemically retain 2.5x106 kg of uranium. Simulations of repository cement/BVG groundwater interactions produced pH 10 at 80°C but no change in the +66 mV Eh. Steel barrel interactions produced an alkaline fluid with Eh -500 mV. Uranium solubility in the high pH repository near field was as high as 10-2.7 M, regardless of steel interactions. Uranium solubility adjacent to the repository (pseudo near field) was controlled by Eh; ranging from 10-13 M in the presence of steel, to 10-2.7 M with no steel. Uranium retention is controlled only by steel barrel durability. Oxidising, natural BVG groundwater will enhance steel barrel destruction. Distant from repository (far field) uranium solubility was 10-5.4 M if Eh was as measured in-situ. Thermodynamic data variations affect the calculation of uranium solubility; uranium near field solubility can be as high as 10-1.4 M. Uranium solubilities in near-field high pH groundwater could be more than 600 times greater than the 10-5.5 M used by the UK Nirex Ltd. in their safety case simulations.

A field-based research study has been undertaken on the River Tame within the industrial city of Birmingham, UK, to understand better the influence of urban groundwater discharge on surface-water quality. The 8 km study reach receives ~6% of its total baseflow (60% of which is groundwater) from the underlying Triassic Sandstone aquifer and flood-plain sediments. An integrated set of surface water and groundwater flow, head and physical/chemical data was collected from installed riverbed piezometers and existing monitoring across the aquifer. Field data and supporting computer modelling indicated the convergence of groundwater flows from the sandstone/drift deposits and variable discharge to the river (0.06 to 10.7 m\(^3\)d\(^{-1}\)m\(^{-1}\), mean 3.6 m\(^3\)d\(^{-1}\)m\(^{-1}\)), much of which occurred through the riverbanks. Significant heterogeneity was also observed in groundwater quality along and across the river channel. Key contaminants detected were copper, nickel, sulphate, nitrate, chlorinated solvents, e.g. trichloroethene, and their biodegradation products. Groundwater contaminant concentrations were generally lower than expected and ascribed to dilution and natural attenuation within the aquifer and riverbed. High concentration plumes were detected, but their effect was localised due to substantial dilution within the overlying water column of the river. Estimated contaminant fluxes were not found to reduce significantly the present surface water quality, which is poor (>30% is pipe-end discharge). Comparative studies elsewhere and further elucidation of heterogeneity and natural attenuation controls are recommended.

Processes controlling the transport of dissolved-phase organic solutes through clay aquitards have been investigated. The study was centred upon a former UK industrial facility at which dissolved-phase aromatic solutes contaminated, and in areas penetrated, a discrete clay bed underlying the site. The lacustrine clay stratum (1-2 m thick) at 6 m bgs located in a sand aquifer was cored in 13 locations and intensively sampled with depth (primarily benzene, ethylbenzene, toluene and styrene). Two types of hydrocarbon invasion profiles were identified; (i) diffusion-based invasion and (ii) advection-dominated invasion. The latter has been shown from extensive physicochemical analysis of the clay cores in the laboratory to be primarily through connected “palaeo-root” holes. Root connectivity has been shown at various scales (serial sectioning, x-ray tomography). The hydraulic conductivity in the case of the advection-based profiles was ~0.04 m/d, whereas in the case of the diffusion-based profiles it was much lower at approximately 3 x 10-5 m/d. Sorption characteristics of the clay have been investigated yielding Kd over 2.98 – 6.95 l/kg and Kf over 2.27- 6.89 μgkg-1/ μgl-1 for PCE and Kd over 0.49 l/kg and Kf over 0.57 μgkg-1/ μgl-1 for benzene. Freundlich isotherms over 3-4 orders of magnitude concentration were found to be near-linear, a phenomenon likely attributed to the occurrence of modern organic matter within the sediments. A 2-D (Fractran) numerical model confirmed that where the clay deposits are homogeneous or contain partially penetrating root holes, slow diffusion dominated invasion will offer significant protection to the lower aquifer with breakthrough times through 1 m of clay of 40 years. Conversely, where the clays contain fully penetrating root holes, advection through the root holes causes much faster contaminant penetration. Matrix diffusion from preferential flowpaths causes contaminant to become distributed completely through the clay stratum. Discharge from the bottom of the clay stratum through root holes will be associated with a significant flux of dissolved-phase contaminant (where 30% of clay is rooted with 7.5 cm spaced root holes, ~0.25 mm aperture, contaminant flux is 0.134 g/m2/d) causing contamination of the lower aquifer. The accumulation of mass in the clay stratum is likely to cause prolonged contamination of the adjacent aquifers should the original source concentrations decrease. Indeed, evidence for such reverse diffusion at this site has been observed in one of the profiles. A 3-D code using high resolution data from x-ray tomography was developed to enable modelling of contaminant transport in finely characterised root holes.

This research is united by both geographical area, principally the Vale of York, and methodology, stressing the use of insect remains in interpreting archaeological environments. Firstly the Cover Sands of North Lincolnshire and the Vale of York are considered. A terminal Devensian age is suggested for the majority of this extensive aeolian deposition and evidence for mode of origin and palaeoenvironment is discussed, with particular regard to insect faunas from within the Sands at Flixborough and Messingham, near Scunthorpe. A brief examination of the nebulous Creswellian industry in relation to the Sands is followed by the study of Mesolithic and Neolithic artifacts from on top of the Cover Sands at Misterton Carr, Nottinghamshire, and the affinities of the earlier part of this assemblage are considered with some current archaeological models of the palaeoenvironment. The trackway beneath Thorne Moor provides an opportunity to examine a local Bronze Age environment and the problems of the genesis of this lowland raised bog and also to discuss more widely the insect fauna of undisturbed forest and the effects of human interference, particularly forest clearance, upon it. The Roman sewer in York contrasts with the largely natural environments examined previously and the attempt to interpret the slight environmental data obtained leads into an essay upon synanthropic insects and the archaeological evidence for their long association with man. This unwanted alliance provides the means to reinterpret a Roman deposit, the Malton burnt grain, which has been linked with the historical events of A.D. 296. The apparent evidence for barbarian attack in northern England is reviewed and a less histrionic interpretation suggested.

Natural aquatic colloids (solids with dimensions between 1 nm and 1 micron) were studied in cave waters that feed secondary carbonates [speleothems]. Results show that during hydrologically quiescent periods, trace metal (Tr) binding (e.g. Cu, Ni, Co) is dominated by humic-like, natural organic matter (NOM), with the smallest NOM-Tr complexes (≤1 to ca. 4 nm diameter) being the least labile at high pH (>pH 10). Partitioning of NOM:Tr between solution and crystal occurs minimally for the strongest complexes, providing a measure of NOM adsorption. Rapid fluxes of coarse (>100 nm) soil organic matter (SOM) and Tr in dripwaters often follow peak infiltration events, the coarse fraction of NOM quenching fluorescence in finer fractions (<100 nm). Termed ‘high-flux’ (HF), this mode of NOM-metal transport contrasts with the humic-like or ‘low-flux’ (LF) mode both hydrologically and chemically, resulting in shifts in trace metal ratios (e.g. Cu:Ni) which are characteristic of changes in the competitive binding of metals for suitable sites in NOM, and diagnostic of qualitative shifts in NOM composition (i.e. relatively more aromatic/hydrophobic). This process becomes manifest in speleothems, resulting in high- and low-flux trace metal end-members and providing information on NOM aromaticity. Changes in HF:LF metal ratios in speleothems are linked to processes in soils which are ultimately mediated by climate (i.e. ambient temperature and infiltrating precipitation); they may provide information on infiltrating precipitation, on the occurrence of surface disturbances (e.g. deforestation) and NOM composition. HF:LF indices complement the existing array of speleothem climate proxies, but each specific system and setting must be understood to ensure their proper interpretation.

No description available.