A peculiar feature of the Himalaya is the occurrence of a system of low‐angle normal faults and shear zones, the South Tibetan Detachment System (STDS), at the mountain crests. The STDS was active during synconvergent tectonics. We describe the STDS‐related sheared rocks along the Dhauli Ganga valley, in the Garhwal Himalaya (NW India), where the Malari granite, reported as an undeformed igneous body crosscutting the STDS, occurs. A detailed multidisciplinary study, integrating field‐based, microstructural, petrographic, and geochronological analyses, was carried out on rocks along this valley. We demonstrate how the noncoaxial ductile portion of the STDS affected the upper part of the Greater Himalaya Sequence migmatite, which experienced peak pressure (P)‐temperature (T) conditions of 0.9–1.1 GPa and ≥750°C at ≥24 Ma. This migmatite has been reworked structurally upward leading to the formation of high‐T sillimanite‐bearing mylonites. Further upward, medium‐T shearing deformed the Malari granite and leucogranite dykes, forming medium‐T mylonites. Ductile shearing was temporally constrained, based on new in situ monazite datings and previously published Ar‐Ar geochronology, between ~20 and 15 Ma. We demonstrate that a preserved ductile to brittle spatial and temporal transition of the STDS deformation exists, with the brittle features overprinting ductile ones. Our data shed new light on the geological evolution of the STDS in the NW Himalaya with implications for the relationship and relative timing of partial melting, granite emplacement, and deformation along low‐angle normal faults.

Despite the Mediterranean sector of the Variscan Belt being fragmented and reworked during Alpine orogenesis, evidence for the activity of a right‐lateral strike‐slip shear zone has been reported in Paleozoic fragments of the belt such as the Sardinian Variscan Basement, the Maures Massif of southern France, and in the Western Alps. To improve this correlation with new structural data, we performed a structural and microstructural analysis incorporating study of the kinematics of flow and petrochronology of a high‐strain zone in the Aiguilles Rouges Massif (External Crystalline Massifs, Western Alps). The results higlight a dextral pure‐shear dominated transpression initiated under amphibolite‐facies metamorphic conditions (~630°C, 0.4 GPa) during Variscan time. The structural evolution of the high‐strain zone is similar to the Ferriere‐Mollières shear zone in the Argentera Massif; both are transpressive shear zones active at the same time (~320 Ma) under similar metamorphic conditions. These two high‐strain zones represent well‐preserved segments of a system of ductile shear zones in the External Crystalline Massifs. The data presented in this study provide improved constraints on the extent, kinematics, and timing of the East Variscan Shear Zone in the Variscan basement of the Western Alps, with implications for refining the correlation between structures in fragments of the southern Variscan Belt. The data also better constrain a segment of a major pre‐Alpine shear zone which may have played an important role during post‐Variscan tectonics as an inherited discontinuity.

Joining geological mapping, structural analysis, petrology and geochronology allowed the internal architecture of the Greater Himalayan Sequence (GHS) to be unraveled. Several top-to-the-south/SW tectonic–metamorphic discontinuities developed at the regional scale, dividing it into three main units exhumed progressively from the upper to the lower one, starting from c. 40 Ma and lasting for several million years. The activity of shear zones has been constrained and linked to the pressure–temperature–time–deformation ( P – T – t – D ) evolution of the deformed rocks by the use of petrochronology. Hanging wall and footwall rocks of the shear zones recorded maximum P – T conditions at different times. Above the Main Central Thrust, a cryptic tectonometamorphic discontinuity (the High Himalayan Discontinuity (HHD)) has been recognized in Central-Eastern Himalaya. The older shear zone, that was active at c. 41–28 Ma, triggered the earlier exhumation of the uppermost GHS and allowed the migration of melt, which was produced at peak metamorphic conditions and subsequently produced in abundance at the time of the activation of the HHD. Production of melt continued at low pressure, with nearly isobaric heating leading to the genesis and emplacement of andalusite- and cordierite-bearing granites. The timing of the activation of the shear zones from deeper to upper structural levels fits with an in-sequence shearing tectonic model for the exhumation of the GHS, further affected by out-of-sequence thrusts.