| Abstract |
Buried valleys are ancient sub-aerial (river) or subglacial drainage networks that are now abandoned and have become infilled by sediment so that they have little or no surface expression in the landscape. Their concealed occurrence can have significant and often unexpected implications for groundwater (e.g. Sandersen & Jorgensen, 2003; Cloutier et al., 2008; Seifert et al. 2008; Oldenborger et al., 2013), hydrocarbon (e.g. Huuse et al., 2012) and geothermal resources (e.g. Allen & Milenic, 2003; Allen et al., 2003). Buried valleys can also contain significant quantities of sand and gravel mineral resources which can act as traps for contaminants as well as pathways into groundwater aquifers._x000D_
The British Geological Survey (BGS) has recognised and identified buried valleys through its survey activities since the 1870's (Mellard Reade, 1873) although no compiled data set has ever been produced. Since the 2000's BGS has also published a Superficial Deposits Thickness Model (SDTM) which models variation in thickness of natural superficial deposits across Great Britain (Lawley and Garcia-Bajo, 2009). However, one limitation of this methodology is that it under-represents the spatial occurrence of linear features such as buried valleys (Kearsey et al., 2018). This work attempts to compile what is currently known about buried valleys from historic survey activities. It also employs a semi-automated method to identify areas of significant superficial deposits thickening based on our current onshore borehole dataset. It cannot be used to say where buried valleys are not present; but it does indicate the locations where based on the recorded evidence and expert knowledge a geologist has interpreted the presence of buried valley. |
