Natural and anthropogenic halite karst subsidence in north Cheshire, UK; comparison of Rostherne Mere, Melchett Mere, Tatton Mere and their surroundings

Abstract

Most of the north Cheshire - Knutsford Group - of meres (lakes) in the UK formed naturally by dissolution of Triassic halite after the Devensian glaciation. Anthropogenic brine extraction in the 19 th and 20 th Centuries produced further subsidence that enlarged some meres and formed the new lake of Melchett Mere. The characteristic features of three meres, Rostherne, Melchett and Tatton are compared here by historical surveys, maps, photographs and LiDAR interpretations. These illustrate the similarities of the natural and anthropogenic subsidence features, which can only be separated by temporal evidence of their formation. Rostherne Mere and Tatton Mere are mainly natural, though deepened or made larger by anthropogenic salt dissolution; Melchett Mere is completely anthropogenic and mainly formed between 1927 and 2003. All three meres are surrounded by landslip scars related to the subsidence. Former brine pumping at Northwich, Plumley and possibly Agden is implicated in the formation of Melchett Mere and the reactivation of natural subsidence at Rostherne and Tatton meres plus The Mere along with Tabley, Pickmere and Budworth meres to the south west. The brine run linkages between these abstraction areas and the subsidence crosses the route of the proposed HS2 railway.

Experimental study of geophysical and transport properties of salt rocks in the context of underground energy storage

“…Natural dissolution is sensitive to climatic changes, as it is to groundwater. Salt karst formation in the United Kingdom was studied by Cooper (2002), who suggested that the karsting was related to changes in the groundwater regime, for example, during the last (Devensian) glaciation (Serridge & Cooper, 2022). Essentially, when the ice sheet melted, groundwater level increased and enabled the circulation of freshwater through salt units interbedded with more permeable units of siltstone, mudstone and gypsum, allowing access of fresher groundwaters to new areas of halite.…”