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.