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This work presents the results of a multidiscipinary study carried out in the southern branch of the Larderello geothermal field (Travale–Montieri area), which was based on the integration of field data with information on the deeper structures as derived from interpretation of seismic reflection profiles and the P – T – t history of the metamorphic substratum as reconstructed from borehole data. Our data document that the structural and metamorphic signature of the metamorphic substratum is chiefly related to a prograde HT–LP metamorphic overprint, ranging in age from c . 2.8 to 0.7 Ma. The metamorphic climax was attained within the K-feldspar zone and equilibrated at P – T conditions of about 0.2 GPa and 650 °C. We interpret these new findings as evidence of Pliocene–Pleistocene thermal metamorphism associated with multiple granite intrusions at shallow levels in the crust. These results (1) add strength to the interpretations emphasizing the contribution of Neogene thermal metamorphism to the tectonometamorphic signature of the basement rocks found at depth in the Larderello geothermal field, and (2) provide insights on the thermal structures of the crustal section hosting the geothermal field and on the modes through which the long-lived positive thermal anomaly operated in southern Tuscany.

The possible effect of pre-deformational, along-strike sedimentary tapers on the structural architecture of thrust wedges accreted above viscous materials has been commonly underestimated or neglected. We illustrate results of an experimental programme specifically designed to study the impact of this parameter on thrust wedge evolution using sandbox analogue modelling. Two series of experiments were performed: the first series was designed to investigate the sensitivity of wedge growth to the along-strike sedimentary taper variability; the second was designed to investigate the sensitivity of a growing along-strike tapered wedge to the convergence rate. Our experimental results indicate that even gentle pre-deformational along-strike thickness variations in foredeep clastic sequences overlying viscous materials, such as evaporites or overpressured shales, can produce dramatic changes in the first-order structural architecture and kinematic evolution of accreting thrust wedges.

The Lanterman Fault is one of the subvertical, NW–SE-striking intraplate shear zones that bound the major Proterozoic to Early Palaeozoic tectono-metamorphic blocks constituting north Victoria Land, Antarctica. This fault zone, several kilometres wide and with an onshore along strike length of about 400 km from the Southern Ocean to the Ross Sea, records almost entirely brittle deformation, producing complex, NW–SE- to north–south-trending, anastomosing dextral fault strands. Brittle faulting is subparallel to the regional subvertical schistosity, indicating that it was superimposed in a broad region that has earlier experienced ductile-dominated deformation. The regional-scale brittle deformation fits into a general kinematic model involving progressive NW–SE dextral simple shear. Two major onshore age constraints exist for brittle faulting along the Lanterman Fault system: (i) involvement of Triassic Beacon and Jurassic Ferrar rocks in faulting; and (ii) the intimate link between right-lateral faulting and Cenozoic magmatism along the southern onshore termination of the fault. We infer that final terrane assembly in northern Victoria Land was the response to late-stage (Cenozoic) right-lateral movements along NW–SE inherited structures, rather than being the result of accretion during the Early Palaeozoic Ross Orogeny.