A Hercynian suture zone in Sardinia : geological and geochemical evidence

Deformation during exhumation of medium‐ and high‐grade metamorphic rocks in the Variscan chain in northern Sardinia (Italy)

“…In this paper, we examine a system of regional-scale shear zones in northern Sardinia (in Anglona and SW Gallura regions; Figures 1 and 2), known to be a system of dextral strike-slip shear zones developed in Late Variscan times ). Carosi and Palmeri (2002), Carosi and Oggiano (2002), Carosi et al (2005) and Iacopini et al (2008) documented the presence of a wide dextral transpressional belt (the Posada-Asinara Line, PAL: Cappelli et al 1992) active around 315-320 Ma (Di . Moreover, we document in the strongly foliated boudins of metabasite have been documented, which generally preserved a complex metamorphic evolution from eclogitic, granulitic, amphibolitic to greenschist facies (Ricci and Sabatini 1978;Ghezzo et al 1979;Cappelli et al 1992;Oggiano and Di Pisa 1992;Franceschelli et al 1982Franceschelli et al , 2005 with references therein; Cortesogno et al 2004;Palmeri et al 2004;Giacomini et al 2005Giacomini et al , 2006.…”

Structural map of Variscan northern Sardinia (Italy)

“…The phase of shortening is associated with nearisothermal decompression and partial melting of UMC in the kyanite stability field (Ferrara, Ricci, & Rita, 1978;Giacomini, Bomparola, & Ghezzo, 2005). The limit between UMC and the lower grade, mainly amphibolitic, LMC, is marked by a 1 -3 km-thick lithospheric shear zone known as the Posada-Asinara Line (PAL) (Cappelli et al, 1991). Metamorphic rocks are widely intruded by a network of late Variscan plutons belonging to the Corsica-Sardinia Batholith (Rossi & Cocherie, 1991).…”

“…The final convergence between the continental blocks was characterized by the development of a wide network of lithospheric strike-slip shear zones, which accommodated the northeastward displacement of Laurussia and Avalonia relative to stable Gondwana from late Visean to Early Permian (Faure, Lardeaux, & Ledru, 2009;Gutiérrez-Alonso et al, 2008;Muttoni, Kent, & Channell, 1996). The pre-Mesozoic basement of north Sardinia is a section of the Variscan orogen equivalent to the Moldanubian domain ( Figure 1) of central Europe (Edel et al, 2013;Matte, 2001;Rossi, Oggiano, & Cocherie, 2009 (Buzzi, Gaggero, & Oggiano, 2008;Casini et al, 2012;Oggiano, Gaggero, Funedda, Buzzi, & Tiepolo, 2010), and a Lower Metamorphic Complex (LMC), made of paragneisses, micaschists, quartzites and subordinate amphibolite boudins (Cappelli et al, 1991;Carmignani et al, 1994).The Visean collisional evolution is testified by exhumation of HP rocks and southward thrusting of UMC onto LMC. The phase of shortening is associated with nearisothermal decompression and partial melting of UMC in the kyanite stability field (Ferrara, Ricci, & Rita, 1978;Giacomini, Bomparola, & Ghezzo, 2005).…”

Petrogenesis of post – orogenic Lower Permian andesites in southern Europe: insights into the collapse of the Variscan range

“…The high-grade complex includes eclogite relics of MORB affinity, whose protolith is dated at 457 ± 2 Ma with peak metamorphism at 403 ± 4 Ma [33], and has thus been interpreted as a Variscan suture [34][35]. The Sardinia-Corsica batholith intruded the Lower Palaeozoic polymetamorphic basement between 340 Ma (northern Corsica; [36]) and 287 Ma (U-Pb SHRIMP method on zircon from A-type granites; [37]).…”

“…% of quartz, and 10 vol. % of garnet (Alm 56-60 Py [34][35][36][37][38][39][40][41][42] ). Mixing and fractional crystallization (MFC) were modelled in a closed system under isobaric, isenthalpic conditions (P = 0.3 GPa).…”