The provenance evolution of the Permo-Triassic fill of the Korotaikha Basin and its constraints for the timing of the Pai-Khoi fold-and-thrust-belt (Russian Arctic)

This study provides insights into the Permo-Triassic evolution of the Pai-Khoi fold-and-thrust-belt in Arctic Russia. The NW-SE trending Pai-Khoi fold-and-thrust-belt (PKFB) is a key feature of the Arctic Uralides, linking the Polar Urals with Novaya Zemlya (see Figure 1). The initiation of deformation along the PKFB is poorly constrained to sometime in the Triassic. Determining the timing of its evolution is essential to better understand the spatial and temporal tectonic differences exhibited along the Arctic Uralides, as well as, the wider tectonic evolution of the South Kara Sea region and its petroleum system.

The Permo-Triassic Korotaikha Basin (KB) located to the south of the PKFB, is widely accepted to be its foreland basin, but its depositional history also spans Uralian orogenesis within the Polar and Subpolar Urals to the east. CASP carried out field work in the central and eastern parts of the remote Korotaikha Basin. Sedimentological studies (facies, palaeocurrent and clast-count) were integrated with subsequent multi-technique sediment provenance analyses on 34 sandstone samples to provide a powerful tool for unravelling changes in sediment provenances. Provenance analyses included petrographic, conventional heavy mineral and single-grain geochemistry (apatite-REE, garnet major element and chrome-spinel) determinations.

Evidence will be presented for the presence of three main sand types. Two compositionally and temporally distinct sand types are characteristic of Permian and Early Triassic strata, and are consistent with derivation from the Polar and Subpolar Urals. The third sand type, typical of late Early to Middle Triassic strata, is interpreted to contain a significant recycled component of Permian to Early Triassic age strata. Deposition of the third sand type is coincident with a fundamental reconfiguration of palaeocurrent directions.

This combination of sedimentological and sediment provenance data is interpreted to constrain the onset of deformation and uplift along the PKFB to the late Early Triassic. PKFB uplift resulted in the formation of a topographic barrier that obstructed sediment transport into the South Kara Basin.