VIENNE LE CHATEAU, FRANCE–There is one strong geological control of warfare in northern France: the high areas are often thick, resistant Upper Cretaceous chalk while the valleys and plains below are usually poorly-consolidated greensands and clays. We’ve already seen these remarkable chalks this summer in Mississippi, Israel, and Germany. Cretaceous Chalk is nearly global in its extent (The White Cliffs of Dover in England and the Chalk Buttes of Kansas are made of it) and it tells us that there was something very different in oceanic chemistry and biology compared to today.
The Argonne Massif is a range of chalk hills running roughly north-south with the Aisne and Aire Rivers cutting through it, along with many smaller streams. The Champagne-Ardenne/Lorraine regional boundary runs through the long axis of the massif. In World War I the Germans occupied most of the highlands in the north since capturing them in 1914. They built relatively spacious and dry bunkers and trenches in the chalk, whereas the French and then later the Americans were mostly confined to the unstable clay-rich lowlands. The most bitter battles here were over the possession of key high points, and the geology of the rocks and soils was a critical factor in success or failure.