Orogen‐Parallel Migration of Exhumation in the Eastern Aar Massif Revealed by Low‐T Thermochronometry

New and published (U-Th)/He data on zircon, apatite, zircon fission track ages constrain the thermal overprint cooling history of eastern Aar Massif, Switzerland. The timing pattern is in agreement with independent kinematic age constraints from exposed shear zones. This suggests that mainly reflect exhumation long-term exhumation-dynamics were controlled by crustal-scale tectonic processes. Results a statistical inverse model reveal significant diachrony along-strike direction. Maximum rates (1 mm/yr) initially located central Massif (from 22 to 10 Ma), then gradually migrated east between Ma present, while continued exhume at slower (0.5 mm/yr). may be explained lateral variations inherited thickness or density accreted European crust. We attribute increase 2 present enhanced glacial erosion. Nevertheless, post reflects continuation noncylindrical massif “growth” eastward orogen-parallel indicates that—although slow rates—thick-skinned buoyancy-driven compressional deformation, likely presence easily erodible flysch units surface, might still ongoing especially Massif. Noncylindrical massif-growth also affect other External Crystalline Massifs orogens, but overlooked because studies often focus single orogen-perpendicular transects.