Basement-involved thrusting, salt migration and intramontane conglomerates: a case from the Southern Pyrenees

The northern margin of the Organyà basin (Southern Pyrenees) has a complex structure in which syn-rift Lower Cretaceous carbonates flank wide Keuper evaporite province, featuring leading edges basement-involved thrust sheets Pyrenean antiformal stack. Recent studies show that diapirs and salt walls grew during extensional episode, conditioning development differentiated depocenters minibasins. role tectonics orogeny not been addressed previous structural studies, but present-day cross-sections indicate evaporite-bearing vertical thickness up to 3000 m Senterada-Gerri de la Sal area. We infer migration was determinant mechanism triggering gentle northward tilting Eocene-Oligocene, recorded La Pobla Segur Gurp syn-tectonic conglomerates large north-directed onlap, opposite main sedimentary influx direction. Contemporaneously, we interpret migration, promoted by conglomerate differential loading, enabled sinking rotation unrooted Nogueres units ( têtes plongeantes ). use new published data for basin, combined with clast provenance from Cenozoic alluvial fan Gurp, understand Lutetian late Oligocene evolution Central South-Pyrenean Unit. tectono-sedimentary this area evacuation patterns are closely related exhumation history stacked Paleozoic hinterland north. In study, correlate movements over mobile substratum paleogeographic changes conglomeratic basins at toe an exhuming orogenic interior.