In collisional orogens, distinguishing the thermal signature of early orogenesis from the preceding rift or from subsequent thermal events is a major challenge. We present an integrated geological and low‐temperature thermochronology study of the Paleozoic Agly‐Salvezines crustal block in the retrowedge of the eastern Pyrenees (France). The northern Pyrenees preserves one of the best geological records of a rift‐to‐collision transition. The Agly‐Salvezines block represents the inverted distal European margin of an Aptian–Cenomanian rift system. Seventeen samples were collected throughout the external orogenic massif and analyzed for low‐temperature thermochronology: zircon (U‐Th)/He dating documents the cooling history of the massif during the initiation and early phase of Pyrenean convergence, while apatite (U‐Th)/He dating completes the record of plate collision. Using inverse and forward modeling of new low‐temperature thermochronology data, we show that the Pyrenean retrowedge records two clear phases of orogenic cooling, Late Campanian–Maastrichtian and Ypresian–Bartonian, which we relate to early inversion of the distal rifted margin and main collision, respectively. An earlier, late Aptian–Turonian cooling history is detected, possibly related to rifting and/or postrift. No cooling is evidenced during the Paleocene during which tectonic quiescence is recorded in the adjacent Aquitaine retroforeland basin. Using our low‐temperature thermochronology data and geological constraints, we propose a crustal‐scale sequentially restored model for the tectonic and thermal transition from extension to peak orogenesis in the eastern Pyrenees, which suggests that both thrusting and underplating processes contributed to early inversion of the Aptian–Cenomanian rift system.

The North Pyrenean Zone represents a fossil hyperextended passive margin, with limited orogenic overprinting, where the thermal and structural patterns associated with crustal thinning and mantle exhumation can be studied on rocks exposed at the surface. The Agly Massif is a tilted ~10‐km‐thick crustal section of Paleozoic and upper Proterozoic magmatic and greenschist to granulitic metamorphic rocks in the easternmost North Pyrenean Zone. We applied multi‐mineral geochronometry and thermochronometry on structural/crustal transects across the massif to understand the exhumation history of the upper and lower continental crust during extreme crustal thinning and mantle exhumation. Integration of zircon and apatite U‐Pb ages provides unprecedented constraints to understand the decoupled versus coupled extensional evolution, exhumation timing of the middle‐lower crust, and the age of juxtaposition of the upper crust granitic pluton with high‐grade gneisses. The Saint Arnac pluton was emplaced and cooled in the upper crust during the Carboniferous and remained at temperatures between 450 and 180 °C until the Late Cretaceous. The middle to lower crust was metamorphosed during the Carboniferous and remained at temperatures >450 °C until the Aptian, when it was rapidly exhumed along a midcrustal shear zone. Deformation was initially decoupled along a midcrustal ductile shear zone until the whole massif was in the brittle field, with structural juxtaposition of the units, and exhumation was coupled and controlled by a major southward dipping detachment fault at the southern border of the massif. The basement massif and synrift sedimentary rocks record significantly different thermal histories during rifting.

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