Abstract We present the first detailed stratigraphic and structural geological map of offshore north Cornwall and Devon, SW England, based on freely available bathymetric data. Although the bathymetry is often spectacular, revealing fold and fault structures exposed on the seabed at a range of scales and with high resolution, interpretation is not as straightforward as it might appear and depends critically upon both accuracy and knowledge of the onshore geology. Unfortunately, onshore stratigraphic controls are limited and restricted to several thin ‘named shales’ whose coastal outcrops are not always well constrained. In addition, the structure is markedly non-cylindrical on local to regional scales, making seaward projection problematic, while the impact of early thrusting on the stratigraphy has often been previously neglected. We therefore developed a workflow to handle the problems we encountered, including: recognition of vertical to horizontal and 3D to 2D projections; variations in bathymetric data characteristics; prediction of expected seabed outcrop geometries based on coastal structures; incorporation of non-cylindrical effects; and problems with quantitative GIS terrain profiles and structural measurements that result in an absence of such measurements. The geological map produced should therefore be viewed as a step forward, but as forming a base for further detailed bathymetric mapping.

Abstract The use of soil evidence to identify an unknown location is a powerful tool to determine the provenance of an item in an investigation. We are particularly interested in the use of these indicators in nuclear forensic cases, whereby identification of locations associated with, for example, a smuggled nuclear material, may be used to indicate the provenance of a find. The use of soil evidence to identify an unknown location relies on understanding and predicting how soils vary in composition depending on their geological/geographical setting. In this study, compositional links between the mineralogy of 40 soils and the underlying bedrock geology, as documented in local-scale geological maps, were established. The soil samples were collected from locations with broadly similar climate and land use across a range of geological settings in a ‘test bed’ 3500 km 2 area of SW England. In this region, the soils formed through chemical weathering of the bedrock, representing a worst case scenario for this type of forensic geolocation owing to the high degree of alteration of the parent rock during soil formation. The mineralogy was quantified using automated scanning electron microscopy–energy dispersive X-ray spectrometry analysis based on QEMSCAN technology. Soil mineralogy and texture as measured using this technique are consistent with the underlying geology as indicated by regional-scale geological mapping. Furthermore, differences between individual units of the same bedrock lithology, such as different granites, were identified by examining trace mineralogical signatures. From an investigative viewpoint, this demonstrated that rapid automated mineral profiling of soil samples could be used, in conjunction with readily available geological mapping or similar datasets, to provide indication of the areas from which a soil sample of unknown origin could, or could not, have been sourced.

Abstract The largest UNESCO World Heritage Site in the UK is found in Cornwall and west Devon, and its designation is based specifically on its heritage for metalliferous mining, especially tin, copper and arsenic. With a history of over 2000 years of mining, SW England is exceptional in the nature and extent of its mining landscape. The mining for metallic ores, and more recently for kaolin, is a function of the distinctive geology of the region. The mining hazards that are encountered in areas of metallic mines are a function of: the Paleozoic rocks; the predominant steeply dipping nature of mineral veins and consequent shaft mining; the great depth and complexity of some of the mines; the waste derived from processing metallic ores; the long history of exploitation; and the contamination associated with various by-products of primary ore-processing, refining and smelting, notably arsenic. The hazards associated with kaolin mining are mainly related to the volume of the inert waste products and the need to maintain stable spoil tips, and the depth of the various tailings’ ponds and pits. The extent of mining in Cornwall and Devon has resulted in the counties being leaders in mining heritage preservation and the treatment and remediation of mining-related hazards.