Abstract Mid-Palaeozoic assembly models for the Arctic Alaska–Chukotka microplate predict the presence of cryptic crustal sutures, the exact locations and deformational histories of which have not been identified in the field. This study presents data on the provenance of polydeformed and metamorphosed strata in the southern Brooks Range Schist Belt and Central Belt of presumed Proterozoic–Devonian depositional age, as well as for the structurally overlying strata, to help elucidate terrane boundaries within the Arctic Alaska–Chukotka microplate and to add new constraints to the palaeogeographical evolution of its constituent parts. The protoliths identified support correlations with metasedimentary strata in the Ruby terrane and Seward Peninsula and suggest a (peri-) Baltican origin in late Neoproterozoic–early Palaeozoic time. Proximity to Laurentia is only evident in what are inferred to be post-early Devonian age strata. By contrast, the North Slope and Apoon terranes originated proximal to Laurentia. The mid-Palaeozoic boundary between these (peri-) Baltican and (peri-) Laurentian terranes once lay between rocks of the Schist/Central belts and those of the Apoon terrane, but is obscured by severe Mesozoic–Cenozoic deformation. Whether this boundary represents a convergent or transform suture, when exactly it formed and how it relates to broader Caledonian convergence in the North Atlantic are still unresolved questions. Supplementary material: Details of the analytical methods together with zircon U-Pb and Lu-Hf isotopic data tables are available at https://doi.org/10.6084/m9.figshare.c.3805696

The Lausitz Group in the easternmost part of Saxo-Thuringia, Germany, forms the largest exposure of partly anchimetamorphic Cadomian basement in Germany. In common with adjoining units to the west, it was deposited in a convergent-margin basin of northern peri-Gondwana. Sedimentary features within the turbiditic graywacke successions suggest continuous accumulation during a deepening stage that followed basaltic-andesitic arc-volcanic activity. The turbidites are irregularly intercalated with tuffaceous graywacke, which was derived from reworked, but only slightly older, basic volcanic material. Petrological and geochemical data reveal a broadly uniform source area for the graywackes with a dissected magmatic arc signature containing exhumed pre-Cadomian basement. Graywackes of the Lausitz Group together with earlier Cadomian basin successions and parts of the pre-Cadomian basement became mobilized during Cadomian subduction-related anatexis. During basin closure, the graywackes were weakly folded with a northerly vergence. Subsequently, they were contact-metamorphic overprinted by granodioritic intrusions, which mark the end of the Cadomian orogeny and show both Cadomian and pre-Cadomian crustal signatures. Superimposed very low-grade S-C textures in gray-wackes of the eastern Lausitz area are due to Variscan processes.