BGS Geology 50k version 9

The BGS Geology 50k datasets are a digital representation of the geological maps of Great Britain at 1:50 000 scale. The data is presented at 1:50 000 scale. Onshore coverage is provided for England, Scotland, Wales and the Isle of Man. Approximately 99% coverage is available and BGS is committed to completing the coverage, and ongoing updates as part of its national survey activities. BGS Geology 50k V9 dataset includes 4 geological themes: bedrock, superficial deposits, mass movement and artificial ground. An additional map component detailing Linear features is also provided. The Bedrock theme describes the main mass of solid rocks forming the earth's crust. Bedrock is present everywhere, whether exposed at surface in outcrops or concealed beneath superficial deposits or water bodies. Geological names are based on lithostratigraphic or lithodemic hierarchy. The lithostratigraphic scheme arranges rock bodies into units based on rock-type and geological time of formation. Where rock-types do not fit into the lithostratigraphic scheme, for example intrusive, deformed rocks subjected to heat and pressure resulting in new or changed rock types; then their classification is based on their rock type or lithological composition. This assesses visible features such as texture, structure, mineralogy. The Superficial theme describes the youngest geological deposits formed during the Quaternary period. They lie on top of older deposits or rocks referred to as bedrock. Superficial deposits were laid down by various natural processes and as such, the deposits are denoted by their BGS lexicon name, which classifies them based on mode of origin (lithogenesis) i.e., 'glacial deposits', 'river terrace deposits' or based on their composition i.e., 'peat'. Most are unconsolidated sediments. The Mass movement theme describes areas where deposits have moved down slope under gravity to form landslips. These landslips can affect bedrock, superficial or artificial ground. Mass movement deposits are described in the BGS Rock Classification Scheme Volume 4. However, the data also includes foundered strata, where ground has collapsed due to subsidence (this is not described in the Rock Classification Scheme). Caution should be exercised with this data; whilst mass movement events are recorded in this layer, due to the dynamic nature of occurrence significant changes may have occurred since the data was released, as such it should be viewed as a snapshot in time (the time frame being defined by the date of survey, not the date of digital map publication). The Artificial theme describes areas where the ground surface has been significantly modified by human activity. Whilst artificial ground may not be considered as part of the 'real geology' of bedrock and superficial deposits it does affect them. Due to the constantly changing nature of land use and re-use/redevelopment, caution must be exercised when using this data as it represents a snapshot in time (the time frame being defined by the date of survey, not the date of digital map publication). The Linear map layer describes linear features that are associated most closely with the bedrock theme, either as an intrinsic part of it (for example, depiction of marine bands) or affecting it (for example depiction of faults between bedrock object). However, landform elements are associated with both bedrock and superficial deposits. The linear features are organised into seven main categories i.e., Alteration Area”, “Bedrock”, “Faults”, “Fold Axis”, “Fossil Horizon”, “Landform”, and “Mineral Vein”, some having additional applicable attribution, for example a LEX-RCS code, or a fault name. All data are available in vector format (containing the geometry of each feature linked to a database record describing their attributes) as ESRI shapefiles and are available under BGS data licence.