ABSTRACT
In this chapter, we consider a particular category of folds: detachment folds. As their name suggests, they are the result of complete separation of the detached cover from the underlying basement, illustrating the concept of thin-skinned tectonics. The development of these structures in compression mode requires two conditions: (1) the existence of a “detachment level” (some authors keep the French word “décollement”), that is, a sufficiently thick layer of low strength, and (2) the existence above of more competent strata that are likely to fold. These concepts are very simple at first sight, and we immediately think of them when we mentally try to imagine a fold. However, we will see that they have some surprises and special counterintuitive features in store.
