ABSTRACT Detrital zircon provenance studies of Precambrian metasedimentary rocks in Wedel Jarlsberg Land and Sørkapp Land, Svalbard’s Southwestern Caledonian Basement Province, were conducted to evaluate local stratigraphic correlations and the role of long-distance strike-slip displacements in assembling the basement of the Arctic Caledonides. The detrital zircon U-Pb age spectra of the late Mesoproterozoic to Neoproterozoic metasediments revealed mainly Mesoproterozoic to Paleoproterozoic age signatures characteristic for a Grenville–Sveconorwegian orogen provenance. These results confirmed a stratigraphic correlation between basement units of southern Sørkapp Land and the Isbjørnhamna Group of Wedel Jarlsberg Land and suggest relocation of the tectonic boundary between the Eimfjellet Complex and the Isbjørnhamna Group above the Eimfjellbreane Formation. Moreover, the results support the Vimsodden Kosibapasset Shear Zone (VKZ) as a major tectonic boundary and highlight the inhomogeneity in the Southwestern Caledonian Basement Province. The detrital zircon age signatures south of the VKZ bear similarities with coeval metasediments of the Northwestern Caledonian Basement Province of Svalbard and other localities in the Greenland and Scandinavian Caledonides. In contrast, the detrital zircon age spectra north of the VKZ are comparable with the high Arctic Neoproterozoic sediments of Baltican affinity. In conjunction with previous studies, the results suggest that the basement units may continue across the traditional boundaries of the Svalbard’s Caledonian basement provinces.

Abstract The metamorphic evolution of the Tjeliken eclogite, occurring within the Seve Nappe Complex of northern Jämtland (Swedish Caledonides), is presented here. The prograde part of the pressure and temperature ( P–T ) path is inferred from the mineral inclusions (pargasitic amphibole) in garnet and intracrystalline garnet exsolutions in omphacite. Peak metamorphic conditions of 25–26 kbar at 650–700 °C are constrained from geothermobarometry for the peak-pressure assemblage garnet+omphacite+phengite+quartz+rutile, using the garnet–clinopyroxene Fe–Mg exchange thermometer in combination with the net-transfer reaction (6 diopside+3 muscovite=3 celadonite +2 grossular+pyrope) geobarometer, the average P–T method of Thermocalc and pseudosection modelling. Quartz inclusions with well-developed radial cracks were identified within omphacite, which suggest that the studied rock could have been buried down to the coesite stability field. Post-peak P–T evolution is inferred from diopside–plagioclase symplectites and amphibole coronas around garnet. Previous studies in northern Jämtland suggest a substantial gap between the P–T conditions of the Lower and Middle Seve nappes: 14–16 kbar and 550–680 °C and 20–30 kbar and 700–800 °C, respectively. The Tjeliken eclogite has been considered previously to be a part of Lower Seve by most authors, but the new P–T data suggest that it may be an isolated klippe of Middle Seve.