The thick Ediacaran–Fortunian infill of a vast retroarc basin, developed as a result of the Cadomian arc accretion, is exposed in the Central Iberian, West Asturian-Leonese and Cantabrian Zones of the Iberian Massif. The vertical stacking patterns of the Cadomian retroarc basin has recorded the spatial-temporal evolution and migration of syn-orogenic depozones in front of a migrating orogenic fold-and-thrust belt. The forebulge depozone migrated from proximal to distal parts of the retroarc basin and was responsible for the onset of major unconformities associated with folding, uplift and generalized denudation. These unconformities are recognized as the contacts of (i) the Lower Alcudian-Domo Extremeño with the Ibor Group/Cíjara Formation in the Central Iberian Zone (gap between ca. 565 and 560 Ma) and (ii) the Mora Formation with the Herrería Formation (gap between ca. 550 and 530 Ma) in the Cantabrian Zone. In the Central Iberian Zone, a Cadomian orogenic collapse unconformity, also referred to as pre-rift unconformity, is intra-Fortunian in age and represented by chaotic megabreccias and olistostromes reflecting a drastic change from slope-related deposits, fed by the erosion and recycling of the Cadomian hinterland, to offshore-dominant substrates episodically punctuated by phoshogenetic processes.