310 research outputs found

    Devonian and Carboniferous stratigraphical correlation and interpretation in the Orcadian area, Central North Sea, Quadrants 7 - 22

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    This report details the stratigraphy and palaeogeography of Devonian and Carboniferous rocks of the northern sector of the UK Central North Sea (the ‘Orcadian Area’) for the 21CXRM Palaeozoic project. The work integrates the lithostratigraphic framework for the Middle Devonian to Late Carboniferous succession in the region of the Mid North Sea High developed in the first phase of the 21CXRM Palaeozoic project (Kearsey et al., 2015), with the Early Devonian to Early Carboniferous succession present in the north Central North Sea. This report describes the stratigraphical correlation of Devonian and Carboniferous strata of the Orcadian Basin and the northern extension of the Forth Approaches into the Witch Ground Graben (Quadrants 7 – 22). A lithostratigraphic framework for the region is presented, building on the work of Cameron (1993) and Marshall and Hewett (2003). For the Devonian strata, the lithostratigraphic framework developed by Marshall and Hewett (2003) is followed. Their study presented a substantial revision of the previous Devonian stratigraphy for the region, particularly related to (1) reassessment of the Devonian - Permian contact and (2) the identification of the Eday Group offshore in the Inner Moray Firth Basin. In this study, onshore outcrops, well data and seismic interpretation (cf. Arsenikos et al., 2016) verify the key elements of the framework of Marshall and Hewett (2003). In addition, well interpretations further define the extent of the stratigraphical units and form the basis of potential source and reservoir horizon palaeogeographic reconstructions for four time intervals within the Devonian succession. For example, the potential source rock of the Orcadia Formation has been interpreted to the north of the Halibut Horst and into the East Orkney Basin, significantly increasing the extent of this unit outside the Inner Moray Firth. A revised lithostratigraphic framework for the Carboniferous strata of Quadrants 14, 15, 20 and 21 is presented. This framework links the Carboniferous succession of the Orcadian Area with equivalent age strata in areas on and surrounding the Mid North Sea High (Kearsey et al., 2015). Well and seismic interpretations have been integrated to better define the extent of Carboniferous units. Regional facies variations for key time intervals in the Early Carboniferous are presented which highlight relationships between the Carboniferous basins of the Witch Ground Graben and Forth Approaches, and those of the Mid North Sea High and adjacent regions to the south. For example, fluvial channel systems have been interpreted within late Visean age coal-bearing, fluvial and lacustrine deposits of the Firth Coal Formation, that are potential feeder systems for Yoredale Formation fluvio-deltaic to marine deposits farther south. This report forms one of a series of outputs from the 21CXRM Palaeozoic project (Orcadian Area) and provides explanatory information for the associated digital datasets (spreadsheet). The Orcadian Area study follows previous work undertaken in the Mid North Sea High area of the Central North Sea (CNS area; Figure 1). Key elements of the regional petroleum geology of the Orcadian area are summarised in an accompanying synthesis report (Monaghan et al., 2016)

    Norham West Mains Farm borehole : operations report

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    A borehole was drilled to a total depth of 501.33 m by Drilcorp Ltd at Norham West Mains Farm, near the village of Norham, Berwick upon Tweed. Work was commenced on the 27th of March 2013 and completed on 7th Obtaining cores from the Norham West Mains Farm Borehole is a major task within the TW:eed Project, which is investigating how limbed vertebrates adapted to walk on land around 360 million years ago (see June 2013. The borehole was fully cored from 10.22 m to its total depth through rocks of the Lower Carboniferous Inverclyde Group. http://www.tetrapods.org/). This was a key stage in the evolution of life on Earth and shaped the future evolution of vertebrates, including the eventual appearance of humans. The project builds on some unique new fossil finds made recently in the Scottish Borders and adjacent areas. Analysis of the borehole will provide a framework upon which this research is to be pinned. This scientific research programme is being undertaken by a consortium of organisations led by the University of Cambridge, and including the universities of Southampton and Leicester, the National Museums of Scotland and the British Geological Survey, and funded through the Natural Environment Research Council

    Devonian and Carboniferous stratigraphical correlation and interpretation in the Central North Sea, Quadrants 25 – 44

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    This report details the stratigraphy and palaeogeography of Devonian and Carboniferous rocks of the UK Central North Sea for the 21CXRM Palaeozoic project. The 21CXRM Palaeozoic project results are delivered as a series of reports and digital datasets for each area. This report describes the stratigraphical correlation of Devonian and Carboniferous strata south of, and over, the Mid North Sea High (Quadrants 25-44) using both well and seismic data. It builds on the work of Cameron (1993a) and others, and uses lithostratigraphy to understand how facies vary across the area. A major outcome of this work is the detailed description of the Cleveland Group, the basinal correlative of the Scremerston, Yoredale and Millstone Grit formations within the offshore extension of the Cleveland Basin

    Model metadata report for Glasgow Geothermal Energy Research Field Site bedrock model

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    This report describes the creation of a 3D geological model developed by the British Geological Survey (BGS) for the UK Geoenergy Observatories (UKGEOS) Glasgow Geothermal Energy Research Field Site (GGERFS). The model represents the bedrock geology, fault network, and underground mine workings. The model has been used to aid borehole prognosis and initial hydrogeological modelling. The 3D geological model described here uses subsurface data held prior to the construction of the Observatory and represents our ‘pre-drill’ understanding of the bedrock and mine geometry. The pre-drill superficial deposits model is also available and is described in Arkley (2018)

    Buried Valleys (onshore) version 1 : scientific report and methodology

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    Buried valleys are ancient sub-aerial (river) or subglacial drainage networks that are now abandoned and have become infilled by sediment so that they have little or no surface expression in the landscape. Their concealed occurrence can have significant and often unexpected implications for groundwater (e.g. Sandersen & Jørgensen, 2003; Cloutier et al., 2008; Seifert et al. 2008; Oldenborger et al., 2013), hydrocarbon (e.g. Huuse et al., 2012) and geothermal resources (e.g. Allen & Milenic, 2003; Allen et al., 2003). Buried valleys can also contain significant quantities of sand and gravel mineral resources which can act as traps for contaminants as well as pathways into groundwater aquifers. The British Geological Survey (BGS) has recognised and identified buried valleys through its survey activities since the 1870’s (Mellard Reade, 1873) although no compiled data set has ever been produced. Since the 2000’s BGS has also published a Superficial Deposits Thickness Model (SDTM) which models variation in thickness of natural superficial deposits across Great Britain (Lawley and Garcia-Bajo, 2009). However, one limitation of this methodology is that it under-represents the spatial occurrence of linear features such as buried valleys (Kearsey et al., 2018). This work attempts to compile what is currently known about buried valleys from historic survey activities. It also employs a semi-automated method to identify areas of significant superficial deposits thickening based on our current onshore borehole dataset. It cannot be used to say where buried valleys are not present; but it does indicate the locations where based on the recorded evidence and expert knowledge a geologist has interpreted the presence of buried valley

    Model metadata report for Glasgow Observatory post-drill bedrock and mine model

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    This report describes the creation of a 3D geological model developed by the British Geological Survey (BGS) for the UK Geoenergy Observatories (UKGEOS) Glasgow Observatory. The model represents the bedrock geology, fault network, and underground mine workings. The model covers an area of 5 by 4 km with a grid resolution of 50 m and smooths out some of the metre scale variability cause by facies variation and faulting. The 3D geological model described here uses subsurface data that was collected during the construction of the Observatory, as well as legacy data, and represents our ‘post-drill’ understanding of the bedrock and mine geometry. A post-drill superficial deposits model is also available

    Urban geoscience report : capacity for 3D urban modelling

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    This report considers opportunities for future 3D urban geology modelling at the BGS. A total of 42 towns and cities in Great Britain were considered in this study, selected based on expected growth areas, e.g. Leeds, Oxford, and/or regionally important urban centres e.g. London, Glasgow. The selected areas also include 13 ‘Cohort 1’ towns identified by the UK Governments Towns Fund, such as Blackpool and Middlesbrough. The review reflects on recent and current 3D urban modelling approaches; considers the nature and complexity of the geology of British towns and cities; evaluates the availability of geological data for 3D modelling and suitable 3D modelling software; and highlights priority areas for innovation. It concludes by providing a series of recommendations for urban geology modelling

    Deep geothermal resource assessment of early carboniferous limestones for Central and Southern Great Britain

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    Early Carboniferous limestones (ECL) host active geothermal systems in Central and Southern Britain. Equivalent rocks have been successfully developed for geothermal energy in Belgium and the Netherlands, but the ECL has yet to be fully assessed as a geothermal resource in Britain. We use established statistical methods to assess the depth, distribution, and geothermal potential of the ECL in Central and Southern Britain. Total heat in place (HIP) resources of 1415 (P10)–1528 (P90) EJ may be present, with a tentative potential recoverable thermal power of 106–222 GW. Further work is needed to understand the resource by identifying areas with sufficient flow rates for successful development such as enhanced permeability zones around faults, fractures or karsts

    3D geological model report for Liverpool, Warrington and Irlam superficial and bedrock model

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    This report describes the data and methodology used to construct the 3D geological model of the artificially modified ground, superficial deposits and bedrock of Liverpool, Warrington and Irlam, NW England (Figure 1). These areas form part of the Lower Mersey Corridor linking Liverpool to Manchester. Historically this been an important transport connection in this region between these cities along the Manchester Ship Canal and more recently by rail and road. The 3D geological model was developed for the purpose of characterising lithological variability within superficial deposits and depth to rockhead. It is intended to be used for the assessment of engineering geological and geological ground conditions and their influence on aquifer vulnerability and recharge potential. The 3D geological model is not intended as a replacement for invasive ground investigation. It provides an additional tool for the development of a conceptual ground model in Liverpool, Warrington and Irlam. The model was constructed to be compatible with, and equivalent to, a detailed 1:10 000 scale geological map. The model therefore includes geological units that would normally be resolved at 1:10 000 scale. The total area of the BGS Liverpool, Warrington and Irlam 3D geological model is approximately 585 km2 and ranges in elevation from 400 mOD to -300 mOD and is suitable for use at scales of 1:10 000 to 1:50 000. The geological model includes the top, base and thickness for each natural and artificial superficial deposit within the area. The BGS Liverpool, Warrington and Irlam 3D geological model report has been separated into the following sections: • Bedrock and superficial geology (Sections 2, 3 and 4): provides the geological context of the Liverpool, Warrington and Irlam geological model areas • Model datasets (Section 5): a description of the data used to inform the BGS Liverpool, Warrington and Irlam 3D geological model and the processes used on these datasets. • Modelled surfaces and volumes (Section 6): a description of the surface horizons modelled for the BGS Liverpool, Warrington and Irlam 3D geological model. • Superficial and bedrock geology modelling workflows (Section 7): the methodology used to model the superficial and bedrock geology in 3D • 3D geological model quality assurance (QA), rules and assumptions and limitations (Sections 8, 9 and 10): a description of the 3D geological model QA procedures; the geological rules and assumptions that were applied to the 3D geological model, and the limitations around the use of the 3D geological model • Uncertainty (Section 11): a qualitative assessment of the uncertainty is described. • BGS Liverpool, Warrington and Irlam 3D geological model images (Section 12): 3D and cross-section images of the 3D geological outputs are provided for the horizons modelled

    UKGEOS: Glasgow Geothermal Energy Research Field Site (GGERFS): initial summary of the geological platform

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    The preferred second UKGEOS site is at Clyde Gateway, in the east end of Glasgow, Scotland. The focus of this, the Glasgow Geothermal Energy Research Field Site (GGERFS), is on characterising and monitoring the subsurface for minewater and hot sedimentary aquifer geothermal energy, and for cooling and heat storage. This report details BGS data and knowledge at late 2016, to define initial characterisation of the ‘geological platform’ relevant for the planning of a geothermal research facility and associated environmental baseline monitoring. The report covers knowledge of the bedrock and superficial deposits geology, abandoned coal mines, hydrogeology, geothermal datasets, geochemistry, remote sensed data, seismicity, stress fields, engineering geology and rock property datasets. BGS holds a great deal of legacy borehole, mining and geochemistry data and has updated existing bedrock and superficial deposits models of the area. However, deep borehole and seismic data are lacking to define the geology and structure of the area below a few hundred metres. Hydrogeological and temperature data are also lacking for the bedrock strata. Regional datasets and knowledge have (and can be further) used to reduce uncertainty and risk in these aspects of the geological characterisation
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