Two tectonic units have been distinguished in the southern part of the Central Iberian Zone, an allochthonous and a para-autochthonous one, separated by a thrust with hanging wall movement towards the NE. The Carboniferous sedimentation is different in the allochthonous and para-autochthonous units. The latter has a thick (6,000-7,000 m) depositional sequence of "Culm" facies essentially continuous with the pre-Carboniferous sedimentation. The allochthonous unit contains three Carboniferous depositional sequences, namely a lower "Culm" facies sequence, a middle paralic facies sequence, and an upper continental facies sequence. These three depositional sequences are arranged as wedges successively cropping out towards the northeast and separated by unconformities. The age, geometry, unconformable relationships and shallowing-upward tendency of the Carboniferous sedimentation in the allochthonous unit are related to the geometry and propagation towards the northeast of the thrust separating the two tectonic units.