Decomposing infinite matroids into their 3-connected minors

Generalizing a well-known theorem for finite matroids, we prove that for every (infinite) connected matroid M there is a unique tree T such that the vertices of T correspond to minors of M each of which is either a maximal 3-connected minor of M, a circuit or a cocircuit, and the edges of T correspond to certain 2-separations of M. In addition, we show that the decomposition of M determines the decomposition of its dual in a natural manner.