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

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, which are separated by an apparent offset of ~ 600 km. The initiation of deformation along the PKFB is poorly constrained, but is suspected to have occurred during the Triassic. Determining the timing of the evolution of the PKFB 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.

The Permo-Triassic Korotaikha Basin is widely accepted to be the foreland basin to the PKFB, but its depositional history also spans Uralian orogenesis within the Polar and Subpolar Urals to the east. CASP field work in the central and eastern parts of the Korotaikha Basin enabled sedimentological studies in both areas to be integrated with subsequent multi-technique sediment provenance analyses of 34 sandstone samples. Petrographic, conventional heavy mineral and single-grain geochemistry (apatite-REE, garnet major element and chrome-spinel) analyses were conducted.

Evidence will be presented for the presence of three main sand types. Two compositionally and temporally distinct sand types, corresponding to Permian and Early Triassic strata, 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.