OR/17/042 Conclusions

Lee, J R, and Hough, E. 2017. A conceptual geological model for investigating shallow sub‐surface geology, Cheshire energy research field site. British Geological Survey Internal Report, OR/17/042.

• This study of the superficial geology of the Ince Marshes area employs a conceptual approach to predicting the range of geological features that may be recorded in the geology. The approach is underpinned by the known range of large‐scale geological processes and environments that have affected the area. The approach also employs a measure of uncertainty to quantify the likely occurrence of a geological feature.
• Weathering of buried bedrock strata (Sherwood Sandstone Group) should be considered ‘virtually certain’ beneath the study area although its distribution and thickness could be variable. Any zone of weathering is likely to contain strata in various states of conversion to soil. The occurrence of weathered bedrock strata within buried valleys is likely to be more limited due to erosion by fluvial and meltwater processes.
• The sub‐drift (rockhead) surface regionally is highly‐irregular and this is also likely to be apparent beneath the search area. Rockhead could be influenced by depth of weathering as well as buried valleys produced by meltwater and glacial erosion which are ‘about as likely as not’ to be present.
• Bedrock strata are likely to be buried beneath a sequence of glacial (till and sorted sediments) and non‐glacial (fluvial and estuarine) deposits. On a regional scale, glacial sediments are likely to form a broad layer‐cake succession comprising a till sheet(s) and associated meltwater deposits. At the local scale, deformation structures including faults, folds, joints and hydrofractures may also be present and penetrate down into and deform the bedrock.
• Non‐glacial deposits probably form the cap to the sequence beneath the study site and were deposited following deglaciation. These are also likely to be heterogeneous.
• Fully understanding the complexity of the natural superficial sequence beneath the study area and its relationship to the modern ground surface and bedrock will require the integration of numerous datasets (borehole, shallow geophysics, site investigation), interpreted within the regional understanding of the conceptual geological model and processes that have been active at the Cheshire Energy Research Field Site.