Mine water geothermal energy could provide sustainable heating, cooling and storage to assist in the decarbonisation of heat and achieving Net Zero carbon emissions. However, mined environments are highly complex and we currently lack the understanding to confidently enable a widespread, cost-effective deployment of the technology. Extensive and repeated use of the mined subsurface as a thermal source/store and the optimisation of operational infrastructure encompasses a range of scientific and technical challenges that require broad partnerships to address. We present emerging results of a pioneering multidisciplinary collaboration formed around an at-scale mine water geothermal research infrastructure in Glasgow, United Kingdom. Focused on a mined, urban environment, a range of approaches have been applied to both characterise the environmental change before geothermal activities to generate “time zero” datasets, and to develop novel monitoring tools for cost-effective and environmentally-sound geothermal operations. Time zero soil chemistry, ground gas, surface water and groundwater characterisation, together with ground motion and seismic monitoring, document ongoing seasonal and temporal variability that can be considered typical of a post-industrial, urban environment underlain by abandoned, flooded coal mine workings. In addition, over 550 water, rock and gas samples collected during borehole drilling and testing underwent diverse geochemical, isotopic and microbiological analysis. Initial results indicate a connected subsurface with modern groundwater, and resolve distinctive chemical, organic carbon and stable isotope signatures from different horizons that offer promise as a basis for monitoring methods. Biogeochemical interactions of sulphur, carbon and iron, plus indications of microbially-mediated mineral oxidation/reduction reactions require further investigation for long term operation. Integration of the wide array of time zero observations and understanding of coupled subsurface processes has significant potential to inform development of efficient and resilient geothermal infrastructure and to inform the design of fit-for-purpose monitoring approaches in the quest towards meeting Net Zero targets.

The ability to identify similar sandstones to a given sample is important where the provenance of the sample is unknown or the quarry of origin is no longer in operation. In the case of building stones from heritage buildings in protected areas, it may be mandatory. Here, a proof of concept for an automated similarity measure is presented by means of a convolutional autoencoder that is able to extract features from a sample thin section and use these features to identify the most similar sample in an existing image library. The approach considers only the shape of the pore space between grains, as, if the pore space alone contains enough information to distinguish between samples, the required image pre-processing and training of a model is greatly simplified. The trained model is able to predict correctly the progenitor quarry of a thin section, from an eight-class dataset of Scottish sandstones, with an accuracy of 47.9%. This prototype, although insufficient for commercial purposes, forms a benchmark for future models against which improvements can be assessed and some of which are suggested. Thematic collection: This article is part of the Digitization and Digitalization in engineering geology and hydrogeology collection available at: https://www.lyellcollection.org/cc/digitization-and-digitalization-in-engineering-geology-and-hydrogeology

ABSTRACTThree collated geochemical surveys of surface water in the Clyde catchment have established the spatial variability in water composition, primarily under baseflow conditions. The waters are broadly pH-neutral to alkaline (maximum pH 8.7) in the lowlands, but mildly acidic in uplands on the catchment periphery. Electrical conductance is relatively high in lowland streams (maximum 8320μgL–1), with lower values in the uplands. Dissolved chromium (Cr; <0.05–971μgL–1) and lead (Pb; <0.05–19.4μgL–1) are of importance due to recognised pollution sources within the catchment. High aqueous Cr concentrations (>5μgL–1) are recorded in urban areas associated with the disposal of alkaline industrial chromite ore processing residue. Under such conditions, Cr probably occurs as Cr(VI). Numerous relatively high Pb values occur in the upland and urban areas. These are likely to be associated with a combination of soil reactions, diffuse pollution and contamination from Pb mineralisation/mining. Pb has a stronger correlation with water pH than with stream sediment Pb content, suggesting that pH has a greater control on Pb mobility than host-rock Pb. Exceedances of water-quality standards are <1% for both Cr and Pb across the catchment. Absolute exceedances are more extreme for Cr than for Pb, highlighting the scale of the Cr pollution problem for urban surface water within the catchment.

ABSTRACTConcentrations of total organic carbon (TOC), total petroleum hydrocarbons, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were determined in 84 near-surface soils (5–20cm depth) taken from a 255km2 area of Glasgow in the Clyde Basin, UK, during July 2011. Total petroleum hydrocarbon range was 79–2,505mgkg–1 (mean 388mgkg–1; median 272mgkg–1) of which the aromatic fraction was 13–74 % (mean 44 %, median 43 %) and saturates were 28–87 % (mean 56 %, median 57 %). ∑16 PAH varied from 2–653mgkg–1 (mean 32.4mgkg–1; median 12.5mgkg–1) and ∑31 PAH range was 2.47–852mgkg–1 (mean 45.4mgkg–1; median 19.0mgkg–1). ∑PCBtri-hepta range was 2.2–1052μgkg–1 (mean 32.4μgkg–1; median 12.7μgkg–1) and the ∑PCB7 range was 0.3–344μgkg–1 (mean 9.8μgkg–1; median 2.7μgkg–1). The concentration, distribution and source of the persistent organic pollutants were compared with those found in urban soils from other cities and to human health assessment criteria for chronic exposure to chemicals in soil. Total concentrations encountered were generally similar to other urban areas that had a similar industrial history. Benzo[a]pyrene concentrations were assessed against four different land use scenarios (irrespective of current land use) using generic assessment criteria resulting in six of 84 samples exceeding the residential criteria. Isomeric PAH ratios and relative abundance of perylene suggest multiple and environmentally modified pyrogenic PAH sources, inferred to be representative of diffuse pollution. ∑PCB7 concentrations were exceeded in 10 % of sites using the Dutch target value of 20μgkg–1. PCB congener profiles were environmentally attenuated and generally dominated by penta-, hexa- and hepta-chlorinated congeners.

Controls on surface water quality in the River Clyde catchment, Scotland, UK, with particular reference to chromium and lead J. M. Bearcock, P. L. Smedley, F. M. Fordyce, P. A. Everett and E. L. Ander 1 British Geological Survey, Environmental Science Centre, Keyworth, Nottingham NG12 5GG, UK. Email: jear1@bgs.ac.uk 2 British Geological Survey, The Lyell Centre, Research Avenue South, Edinburgh EH14 4AP, UK. *Corresponding author

ABSTRACTAn assessment of topsoil (5–20cm) metal/metalloid (hereafter referred to as metal) concentrations across Glasgow and the Clyde Basin reveals that copper, molybdenum, nickel, lead, antimony and zinc show the greatest enrichment in urban versus rural topsoil (elevated 1.7–2.1 times; based on median values). This is a typical indicator suite of urban pollution also found in other cities. Similarly, arsenic, cadmium and lead are elevated 3.2–4.3 times the rural background concentrations in topsoil from the former Leadhills mining area. Moorlands show typical organic-soil geochemical signatures, with significantly lower (P<0.05) concentrations of geogenic elements such as chromium, copper, nickel, molybdenum and zinc, but higher levels of cadmium, lead and selenium than most other land uses due to atmospheric deposition/trapping of these substances in peat. In farmland, 14% of nickel and 7% of zinc in topsoil samples exceed agricultural maximum admissible concentrations, and may be sensitive to sewage-sludge application. Conversely, 5% of copper, 17% of selenium and 96% of pH in farmland topsoil samples are below recommended agricultural production thresholds. Significant proportions of topsoil samples exceed the most precautionary (residential/allotment) human-exposure soil guidelines for chromium (18% urban; 10% rural), lead (76% urban; 45% rural) and vanadium (87% urban; 56% rural). For chromium, this reflects volcanic bedrock and the history of chromite ore processing in the region. However, very few soil types are likely to exceed new chromiumVI-based guidelines. The number of topsoil samples exceeding the guidelines for lead and vanadium highlight the need for further investigations and evidence to improve human soil-exposure risk assessments to better inform land contamination policy and regeneration.

The requirements for quantitative data in geological surveillance are ever increasing; traditional geological maps and 3D models are evolving into quantitative conceptual models based on a broad range of analytical measurements of surface and subsurface properties. The British Geological Survey's Geochemical Baseline Survey of the Environment (G-BASE) project provides one such source of data: national coverage of stream sediment, stream water and soil geochemistry. While this geochemical data is of obvious benefit to our understanding of the present day surface environment, the rich geological diversity of south west England provides an ideal setting in which to showcase the potential of such data to enhance our understanding of the underlying bedrock. In this paper we use compositional data analysis to extract lithostratigraphic information from G-BASE stream sediment data. We find that variations in G-BASE stream sediment geochemistry correspond very closely to mapped variations in bedrock geology. Geochemical variations between the 16 lithostratigraphic domains into which we classify the region provide insight into the distinct geological histories of the lithologies within each domain, particularly in relation to depositional environments and sediment provenance. (C) 2016 The British Geological Survey, NERC. Published by Elsevier B.V.

Geological mapping, the classification of bedrock into distinct identifiable units, has traditionally been conducted at the discretion of the field geologist on the basis of human-observable properties such as those of mineralogical composition and texture. In recent years technological developments have allowed the collection and analysis of ever more advanced quantitative geoscientific datasets. We are now approaching a point where migration of traditional mapping procedures to the digital domain is a feasible reality, with such benefits as consistency, transferability and transparency. One issue that we encounter is that the most geologically informative measurements, such as those of chemical composition, tend to have their sampling density limited by their high cost. Meanwhile, remote sensed data will tend towards extremely high sampling density, but may lack stand-alone geological significance. Nonparametric regression techniques have the potential to negate this issue by modelling the most geologically informative measurements as complex interactions of multiple remote sensed covariates. In this poster we present the use of random forest regression to model soil geochemistry in south west England using remote sensed data, and demonstrate how clustering of the predicted high resolution soil geochemistry is able to differentiate geological units – a process that can be trained to match pre-existing rock classifications. We find that random forest regression based on remote sensed data is capable of predicting element concentrations in soils with superior accuracy to that of ordinary kriging of sparsely sampled point data. Crucially the random forest predictions incorporate the high resolution structure of the remote sensed covariates. This allows geological units, in this case defined purely on the basis of the geochemical composition of their soils, to be mapped with sharp boundaries limited only by the resolution of the remote sensed covariates. It seems likely that such techniques could take centre stage in the future of geological mapping: improving not only on the consistency of classified maps based on human observations, but also allowing the continuous mapping of any geologically constrained variables, such as radon potential, to the best resolution and accuracy that our covariate datasets can support.

Recently, the British Geological Survey’s (BGS) Geochemical Baseline Survey of the Environment (G-BASE) project carried out extensive surveys of rural and urban soil quality in the River Clyde catchment (Clyde basin) on the west coast of Scotland. The Clyde basin is interesting as it extends from a rural upland environment in the south, to the River Clyde estuary in the north. The catchment contains an historic lead mining area known as Leadhills that was active until the mid 20th century. In addition, the estuary and lower reaches of the river formed the transport and shipping links that drove the development of Scotland’s main conurbation – the city of Glasgow, which is centred on the River Clyde. Although heavy industry and mining have now declined, the newly available G-BASE soil datasets demonstrate the impacts of urbanisation and the post-industrial legacy of the Glasgow conurbation as well as of historical mining activities on environmental quality.

Mapping the chemistry of stream and river water across the Clyde Basin serves both to characterise the water quality and assess the dominant controls. Surveys of the Clyde drainage network, undertaken between 2003 and 2010, have generated data encompassing rural and urban streams, rivers, and estuarine water. Mapping displays the large spatial variability in chemical composition across the Basin and the varying influences of controls such as rainfall, land cover and geology. They also display the chemistry of the urban area within the context of the wider drainage network. This presentation highlights the upcoming production of an online atlas and database of surface-water chemistry which characterises the Clyde drainage network and provides a new resource for stakeholder organisations

The distribution of potentially harmful substances in the environment is of growing concern under current environmental protection legislation. Recently the British Geological Survey (BGS) has carried out extensive surveys of rural and urban soil and stream quality in the Clyde Basin to aid land and water management/protection. The results reveal metal concentrations in urban soils are typically up to 2.5 times (median values) that of rural soils as a result of pollution. These newly available datasets demonstrate the impacts of urbanisation and the post-industrial legacy of the Glasgow conurbation as well as of historical mining activities on environmental quality.

This paper provides an overview of regional geochemical mapping using stream sediments from central and south-western Nigeria. A total of 1569 stream sediment samples were collected and 54 major and trace elements determined by ICP-MS and Au, Pd and Pt by fire assay. Multivariate statistical techniques (e.g., correlation analysis and principal factor analysis) were used to explore the data, following appropriate data transformation, to understand the data structure, investigate underlying processes controlling spatial geochemical variability and identify element associations. Major geochemical variations are controlled by source geology and provenance, as well as chemical weathering and winnowing processes, more subtle variations are a result of land use and contamination from anthropogenic activity.This work has identified placer deposits of potential economic importance for Au, REE, Ta, Nb, U and Pt, as well as other primary metal deposits. Areas of higher As and Cr (>2 mg/kg and >70 mg/kg respectively) are associated with Mesozoic and younger coastal sediments in SW Nigeria. High stream sediment Zr concentrations (mean >0.2%), from proximal zircons derived from weathering of basement rocks, have important implications for sample preparation and subsequent analysis due to interferences. Associated heavy minerals enriched in high field strength elements, and notably rare earths, may also have important implications for understanding magmatic processes within the basement terrain of West Africa.This study provides important new background/baseline geochemical values for common geological domains in Nigeria (which extend across other parts of West Africa) for assessment of contamination from urban/industrial land use changes and mining activities. Regional stream sediment mapping is also able to provide important new information with applications across a number of sectors including agriculture, health, land use and planning. (C) 2012 Natural Environment Research Council. Published by Elsevier Ltd. All rights reserved.

The London Earth field survey followed a systematic sampling approach to collect a representative suite of soil samples from across London from a variety of land uses, in order to ensure a robust, unbiased dataset which will represent the baseline geochemistry of the city’s environment. Soil geochemical baseline data can be used to investigate soil quality and geochemical processes in the urban environment, as well as determining where the levels of certain chemical elements are potentially hazardous to humans as well as the natural environment (Johnson and Ander, 2008). In addition to the collection of samples, important accompanying information including observations about the soil colour and composition, and land use details for each sampling site were recorded. This data is an important aspect of the survey as it allows us to assess the site and supports interpretation of the geochemical results. The combination of the geochemical survey data and related field observations provides a comprehensive data resource which will provide valuable information to land use planning and development applications such as urban regeneration as well as provide opportunity for science in the interest of national good. The aim of this report is to present and assess the observational data in order to: i. show the spatial distribution of certain properties of the data set, such as the land use types that were recorded for each sample; ii. to discuss their relative proportions; and, iii. to explain, where possible, any trends or patterns that can be seen in the data. This will be done primarily by presenting maps and graphs of the data and by some discussion of the information they contain. This is intended to provide a useful resource to support the ongoing interpretation of the geochemical data.

The London Earth field survey followed a systematic sampling approach to collect a representative suite of soil samples from across the capital. Samples were taken from a variety of land uses, in order to ensure a robust, unbiased dataset which will represent the baseline geochemistry of the city’s environment. In addition to the collection of samples, important accompanying information including observations about the soil and details for each sampling site were recorded. This data is an important aspect of the survey as it allows us to assess the site and supports interpretation of the geochemical results. The combination of the geochemical survey and related field observations provides a comprehensive data resource which will provide valuable information for land-use planning and development applications such as urban regeneration and contaminated land assessments.

Regional geochemical surveys in Nigeria have consistently found very high concentrations of Zr in the fine ( 2150 Ma, 2200 Ma) to match published absolute ages from the migmatitic gneisses of Nigeria. The ‘anomalous’ high values of Zr, as well as other elements concentrated in resistant ‘heavy’ minerals in Nigeria’s streams is predominantly due to in-stream winnowing processes and may not reflect anomalous concentrations of these elements in the bedrock of catchment areas of the collected stream sediment samples. This conclusion has important implications for using stream sediment chemistry as an exploration tool for primary metal deposits associated with heavy minerals. However, Zr appears to be a good pathfinder element for placer deposits of heavy minerals.