The genesis and evolution of karstic conduit systems in the Chalk

Abstract The Upper Cretaceous Chalk Group is renowned as a major aquifer, but the development of secondary porosity due to karstic conduits poorly understood. Hydrogeological data and evidence from boreholes, sections, tracer tests indicate that dissolutional occur throughout aquifer. Here, we assess for karst, combine it with theoretical models dissolution cave formation produce conceptual model conduits. Dissolution mixing saturated waters contrasting chemistry along key lithostratigraphical inception horizons form extensive isolated conduit networks. These significant proportion enhance permeability. They prime aquifer more integrated networks formed by focused recharge unsaturated surface derived water. However, porous, well-fractured nature means time needed large systems often longer than timescales landscape change. Continued evolution water table lowering halts before they can enlarge into except where geological geomorphological settings are favourable. Groundwater need consider karst permeability this has influence on groundwater flow.