45 research outputs found

    An index to represent lateral variation of the confidence of experts in a 3-D geological model

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    A Confidence Index is proposed that expresses the confidence of experts in the quality of a 3-D model as a representation of the subsurface at particular locations. The Confidence Index is based on the notion that the variation of the height of a particular geological surface represents general geological variability and local variability. The general variability comprises simple trends which allow the modeller to project surface structure at locations remote from direct observations. The local variability limits the extent to which borehole observations constrain inferences which the modeller can make concerning local fluctuations around the broad trends. The general and local geological variability of particular contacts are modelled in terms of simple trend surfaces and variogram models. These are then used to extend measures of confidence that reflect expert opinion so as to assign a confidence value to any location where a particular contact is represented in a model. The index is illustrated with an example from the East Midlands region of the United Kingdom

    A geological fence diagram for England and Wales

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    This report contains a brief description of the data and methodology used to compile the National Geological Fence Diagram (NGFD). The NGFD comprises a network of intersecting geological cross-sections covering England and Wales, to a minimum depth of 1 km and a total section length of approximately 5,500 km. It was compiled by the British Geological Survey (BGS) on behalf of the Environment Agency (EA) and is based upon lines of section agreed between both parties at the inception of the project. The model includes generalised bedrock strata based principally on the BGS 1:625 000 scale digital geological data and superficial deposits greater than 10m in thickness. Additional sources of model data were also considered, largely taken from published BGS data holdings. In total 41 cross-sections were constructed and geologically correlated within the GSI3D software

    The London Basin superficial and bedrock LithoFrame 50 Model

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    This report describes the methodology and datasets used in the construction of the 1:50 000 resolution superficial and bedrock geological model of the London Basin. The London Basin study area was divided into twelve 20 x 20 km tiles, with construction of the first tiles beginning in 2006 and completion of the combined model in 2014. This time period coincided with the ongoing development of GSI3D software which was used to construct much of the model. The GSI3D software was used to calculate a rockhead (base Quaternary and Anthropocene) surface that was then used as a capping surface for the modelling of the bedrock geology in the GOCAD® software. The model complements the corresponding DiGMapGB-50 tiles of the area and consists of about 80 modelled geological units, comprising mass movement (landslip), artificial, superficial, and bedrock. This report supersedes an earlier report detailing the construction of the superficial part of this model (Burke et al. 2013). A glossary of technical terms used is included at the end of this report

    A geological model of London and the Thames Valley, southeast England

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    Many geological survey organisations have started delivering digital geological models as part of their role. This article describes the British Geological Survey (BGS) model for London and the Thames Valley in southeast England. The model covers 4800 km2 and extends to several hundred metres depth. It includes extensive spreads of Quaternary river terraces and alluvium of the Thames drainage system resting on faulted and folded Palaeogene and Cretaceous bedrock strata. The model extends to the base of the Jurassic sedimentary rocks. The baseline datasets used and the uses and limitations of the model are given. The model has been used to generate grids for the elevation of the base of the Quaternary, the thickness of Quaternary deposits, and enabled a reassessment of the subcrop distribution and faulting of the Palaeogene and Cretaceous bedrock units especially beneath the Quaternary deposits. Digital outputs from the model include representations of geological surfaces, which can be used in GIS, CAD and geological modelling software, and also graphic depictions such as a fence diagram of cross-sections through the model. The model can be viewed as a whole, and be dissected, in the BGS Lithoframe Viewer. Spatial queries of this and other BGS models, at specific points, along defined lines or at a specified depth, can be performed with the new BGS Groundhog application, which delivers template-based reports. The model should be viewed as a first version that should be improved further, and kept up to date, as new data and understanding emerges

    Mineral resource information in support of national, regional and local planning : Suffolk

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    This report is one of a series prepared by the British Geological Survey for various administrative areas in England for the Office of the Deputy Prime Minister's research project Mineral Resource Information in Support of National, Regional and Local Planning. The accompanying map relates to the county of Suffolk and delineates the mineral resources of current, or potential, economic interest in the area and the sites where minerals are or have been worked. It also relates these to national planning designations, which may represent constraints on the extraction of minerals. Three major elements of information are presented: • the geological distribution and importance of mineral resources; • the extent of mineral planning permissions and the location of current mineral workings, and • the extent of selected, nationally-designated planning constraints. This wide range of information, much of which is scattered and not always available in a consistent and convenient form, is presented on a digitally-generated summary map on the scale of 1:100 000. This scale is convenient for the overall display of the data and allows for a legible topographic base on which to depict the information. However, all the data are held digitally at larger scales using a Geographical Information System (GIS), which allows easy revision, updating and customisation of the information together with its possible integration with other datasets. The information will form part of a Summary of the Mineral Resources of the East of England Region. The purpose of the work is to assist all interested parties involved in the preparation and review of development plans, both in relation to the extraction of minerals and the protection of mineral resources from sterilisation. It provides a knowledge base, in a consistent format, on the nature and extent of mineral resources and the environmental constraints, which may affect their extraction. An important objective is to provide baseline data for the long term. The results may also provide a starting point for discussions on specific planning proposals for mineral extraction or on proposals, which may sterilise resources. It is anticipated that the maps and report will also provide valuable background data for a much wider audience, including the different sectors of the minerals industry, other agencies and authorities (e.g. The Planning Inspectorate Agency, the Environment Agency, the Countryside Agency and English Nature), environmental interests and the general public. Basic mineral resource information is essential to support mineral exploration and development activities, for resource management and land-use planning, and to establish baseline data for environmental impact studies and environmental guidelines. It also enables a more sustainable pattern and standard of development to be achieved by valuing mineral resources as national assets. The mineral resources covered are sand and gravel, brick clay, hydrocarbons, building stone, chalk and peat

    Mesophyll porosity is modulated by the presence of functional stomata

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    The formation of stomata and leaf mesophyll airspace must be coordinated to establish an efficient and robust network that facilitates gas exchange for photosynthesis, however the mechanism by which this coordinated development occurs remains unclear. Here, we combine microCT and gas exchange analyses with measures of stomatal size and patterning in a range of wild, domesticated and transgenic lines of wheat and Arabidopsis to show that mesophyll airspace formation is linked to stomatal function in both monocots and eudicots. Our results support the hypothesis that gas flux via stomatal pores influences the degree and spatial patterning of mesophyll airspace formation, and indicate that this relationship has been selected for during the evolution of modern wheat. We propose that the coordination of stomata and mesophyll airspace pattern underpins water use efficiency in crops, providing a target for future improvement

    Defining the scope for altering rice leaf anatomy to improve photosynthesis: a modelling approach

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    Leaf structure plays an important role in photosynthesis. However, the causal relationship and the quantitative importance of any single structural parameter to the overall photosynthetic performance of a leaf remains open to debate. In this paper, we report on a mechanistic model, eLeaf, which successfully captures rice leaf photosynthetic performance under varying environmental conditions of light and CO2. We developed a 3D reaction-diffusion model for leaf photosynthesis parameterised using a range of imaging data and biochemical measurements from plants grown under ambient and elevated CO2 and then interrogated the model to quantify the importance of these elements. The model successfully captured leaf-level photosynthetic performance in rice. Photosynthetic metabolism underpinned the majority of the increased carbon assimilation rate observed under elevated CO2 levels, with a range of structural elements making positive and negative contributions. Mesophyll porosity could be varied without any major outcome on photosynthetic performance, providing a theoretical underpinning for experimental data. eLeaf allows quantitative analysis of the influence of morphological and biochemical properties on leaf photosynthesis. The analysis highlights a degree of leaf structural plasticity with respect to photosynthesis of significance in the context of attempts to improve crop photosynthesis

    Industrial minerals of Uganda : an interim report

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    This report contains scientific during a visit to the Uganda Department (GSMD) from 28 July - data gathered by S.J. Mathers Geological Survey and Mines 16 August 1992, together with the results of the laboratory evaluation of some of the samples collected, undertaken at BGS Keyworth by C.J. Mitchell. The study builds on the data already gathered by Morgan (1991) and Mitchell (1992) as part of the ODA/BGS Minerals for Development R&D project initiative in Uganda. The data will be incorporated in an industrial minerals inventory of Uganda which will be prepared in collaboration with the GSMD and the united Nations Development Programme (UNDP). The main aim is to publicize the potential of Uganda's industrial minerals, both for domestic consumption and export, in the hope of attracting the much needed investment for the mining sector
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