South Wales

Carboniferous rocks in this region occur in a broadly east-west trending syncline, the core of which includes the South Wales and Pembrokeshire coalfields (Fig. 5.1). Tournaisian and Visean strata (Avon and Pembroke Limestone groups) represent deposition on a southward prograding carbonate ramp evolving into a carbonate shelf (Wright 1987), in a succession which shows similarities to that of the Bristol and Mendips areas (Chapter 6). The main outcrops, in south Pembrokeshire, Gower and the Vale of Glamorgan, occur along the southern periphery of the coalfields and are commonly affected by Variscan thrusting and folding. Thinner successions occur along what is termed the East Crop and North Crop of the South Wales Coalfield, where much of the Visean succession is absent due to sub-Namurian and intra-Visean unconformities. Namurian fluvio-deltaic deposits (Marros Group) flank the South Wales and Pembrokeshire coalfields. Much of the lower and middle Namurian succession is absent across the region, except in the west of the South Wales Coalfield where only small parts are absent beneath an intra-Namurian unconformity. Westphalian fluvio-lacustrine deposits (South Wales Coal Measures Group) form the South Wales and Pembrokeshire coalfields, located to the east and west of Carmarthen Bay, respectively. Westphalian to Stephanian Pennant alluvial facies (Warwickshire Group) occur in the core of the South Wales Coalfield syncline. Deposition of the South Wales Coal Measures and Warwickshire groups was probably laterally contiguous with those in the Bristol and Somerset coalfields (Chapter 6), but the Usk-Cowbridge High controlled and restricted sedimentation for much of the Carboniferous, with pre-Namurian uplift and erosion removing the Tournaisian and Visean succession. Later uplift is also believed to have caused attenuation of the Warwickshire Group in the east of the South Wales Coalfield. The lithostratigraphical nomenclature for the region is that of Waters et al. (2007; 2009)

Cumbria and the northern Pennines

Carboniferous rocks within the Cumbria and northern Pennines region are bound by the Maryport–Stublick–Ninety Fathom Fault System, which forms the northern boundary of the Lake District and Alston blocks (Fig. 12.1). In the Pennines, the succession occupies the Alston and Askrigg blocks and the intervening Stainmore Trough, a broadly east-west trending graben. Carboniferous strata also flank the Lake District High, occurring at outcrop in north Cumbria, Furness and Cartmel (south Cumbria) and the Vale of Eden, and in the subsurface in west Cumbria. The Askrigg Block succession is separated from that of the Craven Basin (Chapter 11), to the south, by the Craven Fault System

Craven Basin and southern Pennines

Carboniferous rocks within this area occupy the region contiguous with the northern Pennines to the north (Chapter 12) and the Peak District to the south (Chapter 10). All of the stages of the Carboniferous are present at outcrop, with the exception of Stephanian strata, which are absent. The oldest Tournaisian strata crop out within the Craven Basin, and are represented by ramp carbonate rocks (Bowland High Group) deposited on the Bowland High and adjacent Lancaster Fells and Bowland sub-basins. These carbonate rocks are overlain by mainly Visean hemipelagic mudstone and carbonate turbidites (lower part of Craven Group). To the south of the Pendle Fault System (Fig. 11.1), further platform carbonate rocks are proved in the subsurface above the Central Lancashire High (Trawden Limestone Group) and the Holme High and Heywood High (Holme High Limestone Group). These carbonate rocks, which developed during the Tournaisian to late Visean, are known only from well records and geophysical information and are not divided into formations. During the Visean, the platform carbonate rocks pass laterally into more basinal successions in the Harrogate, Rossendale and Huddersfield sub-basins (Craven Group). The lithostratigraphical nomenclature for the Tournaisian and Visean strata is that of Waters et al. (2009), adapted from Riley (1990)

Model metadata report for Swansea-Neath-Port-Talbot

This report describes the creation of city-wide 3D geological of the natural and artificial superficial deposits of the Swansea-Neath-Port-Talbot area. It includes the glacigenic, coastal, estuarine, aeolian and organic deposits of Swansea Bay and the Tawe and Neath Valleys. The 3D geological model does not include bedrock units or geological faults. The construction of the model formed part of a wider study that investigated risks associated with land contamination from past industrial activity including metal processing. The 3D geological model includes ten geological units and thirty one primary cross-sections. Cross-sections were constructed in a northeast-southwest orientation, parallel to the trend of the Tawe and Neath Valleys and northwest-southeast, perpendicular to them to a maximum depth of approximately 60 m below OD. Cross-sections were constructed by considering 752 borehole records that had been manually processed, interpreted and recorded in the British Geological Survey’s Single Onshore Borehole Index and Borehole Geology databases. The distribution of buried units in the Lower Tawe Valley and Neath Valley is defined by geological correlations that determine the geometry of the buried rock basins. Glaciolacustrine deposits and basal till are confined entirely within the buried valleys. Glaciolacustrine deposits are interpreted to be present in the lower part of the Neath Valley although they are only proved west of Briton Ferry (borehole SS79SW65). The presence of these deposits within the remainder of the Neath Valley in the study area is uncertain. Glaciofluvial sand and gravel is present beneath alluvium in the Lower Tawe Valley and is interpreted to underlie tidal flat deposits in the Neath Valley. The presence of glaciofluvial deposits in the shallow offshore area is uncertain and an arbitrary southern limit was taken. Similarly, the presence of till in the offshore area is uncertain and may extend further offshore

A geological background for planning and development in the 'Black Country'

This study, carried out between 1989 and 1992, was commissioned by the Department of the Environment and funded jointly by the Department and the British Geological Survey. Its principal aim was to produce a synthesis of geological information relevant to the planning of land-use and development in that part of the West Midlands conurbation known as the ‘Black Country’. This report is aimed at those involved in planning and development. The results are presented in a style which, it is hoped, will meet the needs of both those with and without previous geological knowledge. Much of the information is provided on a series of ten thematic maps, each of which concentrates on a specific aspect of the geology relevant to the use of land. In addition to the information contained in the report, sources of other more detailed data are indicated

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

Modelling complex geological circular data with the projected normal distribution and mixtures of von Mises distributions

Circular data are commonly encountered in the earth sciences and statistical descriptions and inferences about such data are necessary in structural geology. In this paper we compare two statistical distributions appropriate for complex circular data sets: the mixture of von Mises and the projected normal distribution. We show how the number of components in a mixture of von Mises distribution may be chosen, and how one may choose between the projected normal distribution and the mixture of von Mises for a particular data set. We illustrate these methods with a few structural geological data, showing how the fitted models can complement geological interpretation and permit statistical inference. One of our data sets suggests a special case of the projected normal distribution which we discuss briefly

The Millstone Grit Group (Pennsylvanian) of the Northumberland-Solway Basin and Alston Block of northern England

In the Northumberland–Solway Basin and Alston Block of northern England, some aspects of the stratigraphical and sedimentological relationships between the Millstone Grit Group, the Stainmore Formation (Namurian part of the Yoredale Group) and the Westphalian Pennine Coal Measures Group are uncertain. Also, confusion has resulted from discontinuation of Millstone Grit as a formal lithostratigraphical term north of the Stainmore Basin. This paper presents the evidence for, and describes the nature of, a Kinderscoutian (early Pennsylvanian) abrupt transition from typical ‘Yoredale cyclicity’, characterized by marine limestones in a dominantly siliciclastic succession but including marked fluvial channels, to a sandstone-dominated fluvial succession recognizable as the Millstone Grit Group. Sandbodies present in this region are probably the fluvial feeder systems to many of the fluvio-deltaic successions recorded farther south in the Central Pennine Basin. However, onset of the Millstone Grit Group occurs much earlier to the south, during the Pendleian (late Mississippian), despite the entry of fluvial systems into the Central Pennines Basin from the north. In addition to explaining this counter-intuitive relationship, the paper also recognizes continuation of the fluvial regime into the lowermost part of the Pennine Coal Measures Group

A geological fence diagram for England and Wales

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 construction of a bedrock geology model for the UK: UK3D_v2015

This report is available for download on the BGS UK3D web page to allow the reader to better understand the context and development of UK3D, a national network, or ‘fence diagram model’, of bedrock geology cross-sections. It also explains the development of the metadata underpinning the model and therefore supports use and understanding of UK3D. The pre-existing BGS GB3D model provided the only nationally consistent representation of the bedrock geology of Great Britain to depths of at least 1 km. The latest version of this model was released in 2014 as the GB3D_v2014 and accompanying report (Mathers et al. 2014b). However, the existing GB3D_v2014 model lacked equivalent scale presentation of a fence diagram model for Northern Ireland. It was recognised that in order to provide comparable geological information across the United Kingdom it was necessary to upgrade the model to a UK3D fence diagram model incorporating Northern Ireland, with rigorous peer review performed to enable an enhanced dataset. The objective of this study was therefore to further develop the GB3D model, outlined by Mathers et al. (2014a and b), into a UK3D model by the incorporation of 36 deep boreholes and a framework of 15 cross-sections for Northern Ireland. The appropriate applications for the revised model are for geoscience communication and education to illustrate the national and regional bedrock geology of the United Kingdom to a depth of at least 1 km with an intended resolution of use in the 1:250 000 to 1:1 million scale range. Limitations inherent in the model preclude such applications as detailed geological assessments, resource-reserve estimation and exploration, and any representation or use outside the intended resolution range. The new model produced by this study UK3D_v2015 supersedes the earlier 2014 version for England and Wales, for which areas of the fence diagrams remain the same. The Scottish portion of the model remains unchanged from the earlier 2012 version. The new dataset is a wholly owned BGS product and as with its forerunners it is freely available from the BGS website http://bgs.ac.uk as downloads in a variety of formats