Cld-St-And-Bearing Assemblages in the Central Southalpine Basement: Markers of an Evolving Thermal Regime during Variscan Convergence

Multiscale structural analysis is carried out to explore the sequence of superposed pre-Alpine chloritoid–staurolite–andalusite metamorphic assemblages in polydeformed Variscan basement upper Val Camonica, central Southalpine domain. The dominant fabric Camonica late-Variscan S2 foliation, marked by greenschist facies minerals and truncated base Permian siliciclastic sequences. intersection with sedimentary strata defines a age limit on tectono–metamorphic evolution exhumation basement. detailed survey revealed that older S1 foliation was locally preserved low-strained domains. composite resulting from combining S1a S1b: metapelites, supported chloritoid, garnet, biotite developed before S1b, which staurolite, biotite. S1b at intermediate pressure amphibolite conditions during convergence, T = 520–550 °C P ≃ 0.8 GPa, 550–650 0.4–0.7 GPa. special feature metapelites andalusite, formed between late D1b early D2 tectonic events. Andalusite 520–580 0.2–0.4 GPa pre-Permian times, after peak collision subsequent deposition covers. It follows andalusite has different significance as compared other occurrences Alps, where mostly high-temperature rocks Permian–Triassic times.