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Syn‐rift extensional faults play a significant role during the early stage of rifting. Constraining the age of faulting, and how and when deformation shifts from the proximal to the distal margin areas, is crucial for the reconstruction of the rifting process. Previous assessments of the structural and temporal evolution of rift‐related faults of the Adria proximal margin have primarily relied on indirect biostratigraphic evidence. Additionally, the majority of rift‐related faults underwent tectonic inversion during the Alpine orogeny. In this study, in‐situ U‐Pb geochronology was applied on syn‐kinematic calcites to unravel the activity of the Amora Fault, a remarkable example of a Jurassic growth fault unaffected by the Alpine orogeny. The obtained ages, spanning from Hettangian to Callovian, extend the AF activity beyond the previously established Early Jurassic time. This chrono‐structural model has significant implications on the role of major extensional faults in focusing deformation throughout the rift system's evolution. [ABSTRACT FROM AUTHOR]

The Early Permian in the present-day Europe area was a time when a major tectonic shift occurred, leading from the tectonic collapse of the Variscan orogeny to the crustal extension and thinning that characterized the Early Permian times. Crustal extension was associated with extensive magmatism at different crustal levels: from gabbro in the lower crust or at the mantle/crust transition to subaerial high-SiO2 volcanic activity. In the whole Southalpine Domain, the Early Permian intrusive bodies occur from the west (e.g. Ivrea-Verbano Complex and "Graniti dei Laghi") to the east (Ifinger, Brixen and Cima d'Asta intrusive complexes). Among these, in the central Southern Alps (comprised between the Giudicarie Belt and the Lake Como), minor intrusive complexes also occur. The Val Biandino Intrusive Suite consists of two magmatic units: the Val Biandino Quartz-Diorite (VBQD) and the Valle di San Biagio Granite (VSBG). The first of them consists of gabbro-diorite to granodiorite bodies associated with leucocratic cordierite-bearing granitic dikes that intruded the pre-Permian basement. To the west, a W-dipping normal fault of Permian age represents the boundary between this unit and the Valle di San Biagio porphyric granite. All rock varieties of the Val Biandino Intrusive Suite display a high-K calc-alkaline affinity with metaluminous to peraluminous character. Field crosscutting relationships point to a late generation of the cordierite granites of the Val Biandino Quartz-Diorite unit with respect to the more mafic types. SHRIMP U–Pb zircon dating provided an age of 285.2 ± 1.9 Ma for a cordierite granite of the Val Biandino Quartz-Diorite unit and 283.2 ± 1.9 Ma for the porphyric Valle di San Biagio Granite. Geochemical data suggest that gabbro-diorite, quartz-diorite, granodiorite and leucogranite are not co-magmatic. The existing gaps in term of SiO2 wt% and the higher HREE contents in mafic and intermediate rocks with respect to granite coupled with similar LREE in all rocks support this hypothesis. The high Rb/Sr ratios (> 1) in leucogranite, together with the occurrence of white mica and cordierite point to a significant contribution of crustal partial melting in their genesis. The Val Biandino Intrusive Suite was likely formed through the interaction of magma genesis at the mantle/crust transition and partial melting of the heterogeneous pre-Permian basement of the Southalpine Domain. This scenario explains the strong heterogeneity displayed by the relatively small intrusive complex and the strong crustal signature exhibited by all the magmatic types of the Val Biandino Intrusive Suite. [ABSTRACT FROM AUTHOR]

The northern Adamello batholith (European Southern Alps) is crosscut by E-W trending pseudotachylyte-bearing paleoseismic fault zones composed of multiple subparallel fault strands. The main faults are the Gole Strette Fault Zone (GSFZ), here discussed in detail, and the Gole Larghe Fault Zone (GLFZ). The western ending of the GSFZ intersects the propagation of the Gallinera Thrust, a regional structure of Late Cretaceous age, which was truncated and dismembered by the late Eocene - early Oligocene emplacement of the Adamello batholith. Fault slip analysis and paleostress reconstruction suggest that the GSFZ and the Gallinera Thrust were both active during dextral transpression related with Oligocene orogen-parallel shearing along the Periadriatic Fault System. The remnants of the Gallinera Thrust within the Adamello were reactivated as dextral-reverse faults and do not include pseudotachylytes. The pseudotachylyte-bearing GSFZ shows changing structural features from west to east: the fault dip angle decreases from 80° to 45°, the slip vector passes from strike-slip (pitch of 20°) to oblique (pitch of 35° to 45°), and the fault zone thickness increases (> 800 m at the intersection with the GLFZ). The GSFZ is an immature and strong fault as indicated by (i) the local geometry controlled by precursor joints; (ii) the along-strike segmentation; and (iii) the spread of seismogenic faults into wide fault zones. • More than 20-km-long exhumed seismogenic faults mapped in the Adamello batholith. • Seismogenic faults record Oligocene NNW-SSE shortening in a transpressive regime. • Coseismic slip vectors and fault zone structural complexity vary along strike. [ABSTRACT FROM AUTHOR]