U–Th–Pb (LA-ICP-MS) Dating of Detrital Zircons from Jurassic Deposits of the Franz Josef Land Archipelago (Russian Arctic) and the Evolution of Their Provenance

We present the results of U–Pb dating of detrital zircon from Lower to Middle Jurassic sedimentary rocks, sampled from natural outcrops during fieldwork on Hooker, Hayes, Ziegler, Jackson, and Graham Bell islands of the Franz Josef Land archipelago. Considering the geographic distribution of the studied samples, we characterize the spatial distribution of detrital zircon ages from Early Jurassic (Pliensbachian) and Middle Jurassic (Bajocian–Bathonian) strata across the archipelago. Based on this, we reconstruct the evolution of sediment source areas in both time and space. The data show that during the Pliensbachian and Bajocian, the main provenance areas were uplifts composed of metamorphic (Meso- to Neoproterozoic), magmatic (Cambrian and Late Devonian–Carboniferous), and Cambrian–Triassic sedimentary rocks, which were exposed during Late Triassic to Early Jurassic uplift in the northeastern Barents Sea region. By the Bajocian–Bathonian boundary, most of these uplifts had been significantly eroded. A major transgression, initiated in the Toarcian, culminated at the end of the Bajocian, leading to an expansion of marine sedimentation and a substantial reduction in the extent of continental landmasses. The dominant sediment sources at that time were likely limited to small land areas composed of Permian and/or Lower to Middle Triassic strata.