Abstract
For the first time tectonic and microtectonic structures observed in the pits of HUNOSA in the Central Coal Basin, subunity of the Cantabrian Zone, are described. They are classified according to their association with the phases of deformation of the coal field in agreement with the following scheme: Internal deformation of coal seams, parasitic flexural folds and faults (on a metric a decametric scale) associated to the main phases of the hercynian folding; vertical strike-slip faults and subhorizontal fractures on the coal field scale, and gravitational microtectonics related to the latest stages of deformation of the hercynian orogeny; tectonic structures probably associated with an initial alpine distending episode. The description of subhorizontal fractures as well as of those associated with the alpine episode are novel, no previous references having been reported.
