How did geology affect D-Day?

Deemed the most ambitious amphibious operation in human history, the Normandy Landings, known as 'D-Day', led to the liberation of France from German occupation and subsequently the end of the Second World War. Throughout the public consciousness, the term 'D-Day' is synonymous with unity and victory in the darkest times, but little is widely known of the role which geoscience played in the success of this operation.

Planning for D-Day began a year before the historic capture of the beaches, when Major (later Lieutenant Colonel) William Bernard Robinson King (1889–1963), the Staff Officer (Geology) of the invasion force pointed out that the region best geologically suited for rapid construction of Allied airfields was that of Normandy. King was released from the army in 1943, but his role was taken up by Captain (later Major) Fred Shotton (1906–1990) after his return from North Africa.

British military geologists, including those of the 21st Army Group, the team on which Shotton served, and the Inter-Service Topographical Department, went on to create specialist geologic maps of Normandy. These vital resources indicated several key features of the landing sites, including the locations of natural hazards which would hinder terrestrial and aquatic vehicle mobility; the suitability of ground for construction of storage depots; areas best suited to provide potable groundwater; and identification of quarrying material for road construction. 

Due to the clandestine nature of these operations, few of the geological maps were printed and even fewer survived the war. Those printed were once classified ‘Bigot’ (a high-level of security created for documents associated with the Normandy invasion) or ‘Top Secret’, but a selection of maps generated by the 21st Army Group became part of Shotton's personal collection post-war. As such, these accompanied him to the University of Sheffield in 1945 and to the University of Birmingham in 1949, and so the Lapworth Museum of Geology holds an extensive collection of these maps in its Shotton Archive.