New data on Upper Carboniferous-Lower Permian deposits of Bol'shevik Island, Severnaya Zemlya Archipelago

Abstract

We present here a detailed study of the Upper Carboniferous-Lower Permian stratigraphy of Bol'shevik Island in the Severnaya Zemlya Archipelago, consisting of the analysis of sedimentary structures and lithostratigraphy, U/Pb detrital zircon dating and structural studies. The preserved sedimentary structures suggest that the studied strata were deposited in a relatively small meandering fluvial system. U/Pb dating of detrital zircons reveals that theUpperCarboniferous- Lower Permian sandstones contain a primary age population ranging from 450 to 570 millions of years, with a predominance of Early-Middle Ordovician zircons. This detrital zircon distribution indicates that the studied formations were derived locally from the erosion of Lower Ordovician deposits of Bol'shevik Island or elsewhere in the archipelago. Our structural studies suggest that Upper Carboniferous-Lower Permian deposits are deformed into a series of west- north-west verging open asymmetric folds, suggesting a west-north-west direction of tectonic transport and that deformation across the island is post-Early Permian in age.