New U-Pb sensitive high-mass resolution ion microprobe (SHRIMP) data from detrital zircons within the Orlica-Śnieżnik Dome provide new insights into the stratigraphic and palaeogeographic position of assumed relict Precambrian basement preserved in the Variscan collisional orogen of the West Sudetes, SW Poland. Hitherto, the Młynowiec Formation and the Stronie Formation within the Orlica-Śnieżnik Dome were assumed to represent two metavolcano-sedimentary successions of Proterozoic and early Palaeozoic age, respectively. However, when previous U-Pb data and mapping data from the Orlica-Śnieżnik Dome are combined with the new detrital zircon isotopic ages both from paragneisses within the Młynowiec Formation and from light-coloured quartzites and mica schists within the Stronie Formation, the result strongly suggests that the protoliths of these two formations actually form a continuous succession. This continuous succession is herein designated the Młynowiec-Stronie Group. The rocks of this group were deposited during middle Cambrian-early Ordovician times (c. 520-470 Ma), presumably at the northern edge of West Gondwana after the 10-20 Ma period of tectonic quiescence that followed the terminal stage of the Cadomian collisions. Monotonous Młynowiec metagreywackes form the lower part of the succession, and the lithologically diverse schistose Stronie Formation forms its upper part. The change from greywacke (Młynowiec) to volcano-sedimentary (Stronie) facies coincided with the onset of rather short-lived volcanic activity which climaxed around 505-495 Ma and which supplied the volcanogenic components to the Stronie Formation. No 'Cadomian unconformity' has been observed in the region. Xenocrystic zircons from the Młynowiec-Stronie Group retain records of Archaean (3.0-2.3 Ga), Palaeoproterozoic (2.1-1.8 Ga) and Neoproterozoic to early Cambrian (660-530 Ma) zircon-forming events. These zircon ages, together with the lack of 1.7-1.2 Ga zircon ages, suggest that the source areas for the metasedimentary rocks may have been the West Africa craton, which therefore differs from the Amazonian affinity of the adjacent Brunovistulia Terrane. Nevertheless, two zircons, c. 1.0 and 1.1 Ga old, respectively, indicate that the Młynowiec-Stronie Group sedimentary basin must have still been within the delivery reach of detritus ultimately derived from the Grenvillian-age belt(s). The detrital components of the supracrustal formations of the Orlica-Śnieżnik Dome were mainly derived from Neoproterozoic zircon-bearing crystalline rocks that were accreted to, and included in, the Cadomian basement in several intrusive pulses that culminated at 660-640 Ma, 620 Ma and 570-530 Ma.

Quantitative analyses of garnet -bearing epidote amphibolite (hereafter garnet amphibolite) from the Funaokayama unit, western Kii Peninsula of the Sanbagawa belt reveal a previously unrecognized high -grade part of the Sanbagawa metamorphism. Petrographic observations suggest that the garnet amphibolite underwent three stages of metamorphism (M1, M2 and M3). Records of M1 are preserved as syn -tectonic prograde -zoned garnet and its inclusions. Pseudosection modeling reproduces the observed M1 assemblage garnet + amphibolite + epidote + phengite + quartz and the growth zoning of garnet records the pressure (P) -temperature (T) evolution from 0.8 GPa, 570 °C to 1.3 GPa, 590 °C. Therefore, this garnet growth and associated deformation (D1) took place during subduction up to eclogite facies conditions. The garnet rim compositions and inclusions of epidote, titanite, rutile and quartz (5titanite + 2clinozoisite = 5rutile + 3grossular + 2quartz + H 2 O) give consistent peak -P estimates of 1.3 -1.9 GPa. The garnet contains quartz inclusions retaining residual pressures of up to ~ 0.7 GPa, which is as high as the values reported in well -characterized eclogite samples in central Shikoku. The inferred peak -P conditions in the eclogite facies is further supported by the occurrence of aragonite in associated pelitic schist. The assemblage hornblende + epidote + titanite + quartz + albite in the matrix and its equilibrium conditions of ~ 0.8 GPa, 580 °C suggest decompression to the epidote -amphibolite facies (M2). The M2 minerals locally show replacement by the mineral assemblage actinolite + epidote + chlorite + titanite + calcite + quartz + albite, suggesting a partial re -equilibration in the greenschist facies (M3). M2 and M3 are synchronous with the main phase of ductile deformation during exhumation (D2). Despite the absence of the omphacite + quartz assemblage, it is likely that eclogite facies metamorphism in the Sanbagawa belt can be extended to western Kii Peninsula.