Multigrain concentrates of hornblende and muscovite together with whole-rock slate/phyllite samples have been dated Variscan deformation systematically prograded diachronously eastward across the orogen as new crustal material was added along the front of the developing orogenic wedge. However, the entire orogen remained tectonically active with different structural features forming at different times and at different places. An average propagation rate of ca. 5 kmlm.y. is suggested by consideration of a 20-25 Ma difference in correlative fabric ages and present separations.

The Cantabrian Zone constitutes the external zone of the Variscan orogenic belt in the northwest of the Iberian Peninsula. Within it a large number of thrusts and folds can be observed which define the form of the Asturian Arc. Tectonostratigraphically, two units can be distinguished: a pretectonic one and a syntectonic one. The time of the transition between the two units lies close to the Devonian‐Carboniferous boundary. The major allochthonous units of the Cantabrian Zone display varied geometries (duplexes, imbricated thrusts, out‐of‐sequence thrusts, etc.). The allochthonous units were emplaced in a foreland propagating sequence with movement age ranging from Westphalian B to Stephanian. Movement directions changed from one major unit. As a whole, the movement directions converge toward the core of the Asturian Arc, and are best interpreted in terms of a progressive series of rotational displacements, leading to a final disposition of major units similar to that of the leaves of a photographic iris. The folds were initiated at the same time as the motion of each nappe unit, and each type of structure represents the hanging wall adaptation to the development of a lateral and longitudinal staircase thrust surface topography. These folds suffered tightening after the emplacement of the thrust unit in which they occur, as a result of the different direction of movement of the next thrust unit propagating from beneath.

Cistus species are obligate seeding, early colonizers that follow disturbance, particularly fire, in Mediterranean ecosystems. We studied seed release, seed dispersal and soil seed populations in stands of Cistus ladanifer and C. libanotis. Seed release started in mid- to late summer (C. ladanifer) or in early autumn (C libanotis), and continued for a very extended period: 8-10 months in C. ladanifer, and for a mean of 16 months in C. libanotis. The xerochastic capsules of both species released seeds by successive dehiscence of the locules. All capsules begin to dehisce simultaneously at the start of the seed release period, but in C. libanotis capsule fragmentation replaced dehiscence early in the seed release period. In plants of both species, seed shadows were characterized by a peak of density beneath the plant canopy and a very short tail of much lower densities, indicating that seeds are concentrated beneath mother plants when dispersed. Nevertheless, in late May, at the onset of the fire season, soil seed densities beneath plant canopies were low compared with densities expected from seed shadows, but were apparently high enough to allow recovery of the stands if a disturbance, such as fire, had taken place. Seed-eating Bruchidae in summer and granivorous ants during the seed release period were apparently the main causes of seed losses. Results suggest that in both Cistus species, the staggered seed release could constitute an efficient risk-reducing trait. The plant pool of seeds existing throughout most of the year could be a relevant component of Cistus seed banks.

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