Basement?Cover Decoupling During the Inversion of a Hyperextended Basin: Insights From the Eastern Pyrenees

Deformation processes related to early stages of collisional belts, especially the inversion rifted systems remain poorly constrained, partly because evidence these is usually obliterated during subsequent collision. The Pyrenean belt resulting from a Cretaceous hyperextended margin associated with high-temperature and low-pressure metamorphism in Internal Metamorphic Zone (IMZ), good example for studying stage orogenic deformation. This study focused on Eastern Pyrenees where relation between inverted Mesozoic basins their basement are well-preserved. By using maximum temperatures (Tmax) estimated by Raman Spectroscopy Carbonaceous Materials geothermometer structural data, we describe spatial distribution various tectono-metamorphic units. Tmax recorded sedimentary cover exposed north south Paleozoic block (Agly massif), exceed 550°C, while metasediments autochthonous show < 350°C. metamorphic affected ductile deformation, only brittle Post-metamorphism breccias observed cover, which interpreted as décollement level Upper Triassic evaporites. Unlike previous models suggesting that separated two (Boucheville Bas Agly) rifting, propose large displacement single basin thrust above block. novel interpretation emphasizes general allochthonous position former rift (IMZ) thrusted along decoupling layer.