Influence of late Paleozoic Gondwana glaciations on the depositional evolution of the northern Pangean shelf, North Greenland, Svalbard, and the Barents Sea

Outcrop and subsurface data from the central northern margin of the Pangean shelf in North Greenland, Svalbard, and the Norwegian Barents Sea record the depositional response of a Northern Hemisphere subtropical shelf to Late Carboniferous-Early Permian (Bashkirian-Sakmarian) Gondwana glaciations. The dominant motif is that of meters to tens of meters of exposure-capped cycles of carbonates, mixed carbonates, and siliciclastics and, in older stratigraphic levels, siliciclastics and gypsum. Halite-gypsum-carbonate cycles developed in deeper, isolated basins. Individual cycles of carbonate and mixed carbonate-siliciclastics reflect deposition during the later stages of transgression, sea-level highstands, and high-frequency and high-amplitude glacio-eustatic sea-level fluctuations. The Moscovian sections in North Greenland are composed of 43 such cycles, each of which apparently reflects sea-level fluctuations linked to the 100 k.y. Milankovitch cycle. The stratigraphic distribution of subaerial exposure surfaces indicates that during Late Carboniferous-Early Permian time, the northern Pangea shelf repeatedly changed from being a shallow subtropical carbonate platform to a vast subaerially exposed carbonate plain, and it implies sea-level amplitudes in excess of 50 m. A major Gondwana deglaciation event is recorded in early Sakmarian shelf successions offshore northern Norway, where rapid flooding led to sediment starvation over an extended period of time, and when sedimentation finally resumed, the cyclic motif is absent.