Geological framework model and surface data for the area south of Ammanford

Background The original objective of this work was to a ssemble a 1:50 000 (50k) resolution 3D Geological Framework Model for an area south of Ammanfor d. The model was to have two main purposes: 1. To form the basis for a communication tool to present the 3D geological understanding of the area to a range of stakeholders; and 2. To support the reinterpretation of th e geological succession mapped at surface. This study specifically excludes the further development of th e Framework Model to include hydrogeology, hydrochemistry or rock mechanics and does not include any consideration of potentially suitable resources such as Coal Bed Methane. This report provides the explanation of the me thodology and how this model was generated. Additional outputs of the study include: 1. An ArcGIS project containing the da ta used to compile the model; and 2. Surface observations of the geology collected foll owing Sigma workflows, held in a GIS. Development of a 3D geological framework model A 1:50 000 resolution 3D geological framework model was successfully constructed for the study area using the Geological Surveying and Investigation in 3D (GSI3D) software package, developed partly in house at BGS, which can be used readily by geologists to construct a series of cross-sections that can more clearly display the geological succession. Models of this type have the potential to be accessible to members of the public and used by geologists to assess the potential location of resources , not evident from traditi onal 2D geological maps. The approach followed was to construct a fence diagram of 12 cross-sections using GSI3D. These sections encompass the entire study area and using the geologists’ expert knowledge to incorporate surface and subsurface data (24 deep boreholes and structural contour information from published geological maps) provide an inte rpretation of the geolog ical succession at Bed, Member and Formation level, consistent with BGS 1:50 000-scale (50k) geological maps of the area.