A 3D geological model of the superficial deposits of the Holderness area

This report and accompanying 3D geological model were produced for the Environment Agency. The report describes the Quaternary geology of the study area, from Hull in the south to Flamborough Head in the north (Figure 1), and supersedes a previous study carried out in 2008 for the Hull area. The description and spatial distribution of each geological unit is based on interpretations from a 3D geological model, which was constructed using digital geological map data and 1398 boreholes taken from the BGS Borehole Geology database, plus borehole data supplied by the Environment Agency. The data from the EA were included in the 3D model where they fell along lines of cross-section and were particularly useful where gaps occurred in the BGS records. The 3D model was constructed using GSI3D® software and methodology (described in more detail at http://en.wikipedia.org/wiki/GSI3D). The 3D model comprises 74 cross-sections (plus additional ‘helper sections), it includes 26 geological units and covers a total area of approximately 1280 km2. A NEXTMap 100m cell size DTM was used to cap the 3D model, which was combined with bathymetry data of the Humber Estuary, supplied by ABP Marine Environmental Research. The 3D model has revealed extensive sand and gravel units both beneath and within the main till sequence, plus a deep sand and gravel-filled buried channel that cuts into the Chalk bedrock in the Holderness coastal area. A morainic deposit, consisting of intermixed sand and gravel with till, in places extending down to bedrock, was identified in the previous study carried out for the Hull area. These more permeable units are likely to impact on groundwater in the area.