Latest Pleistocene and Holocene paleoenvironments of the Franz Josef Land region, northern Barents Sea, Arctic Russia
Scholarly Edition
Overview
abstract
New marine and terrestrial geologic data from the Franz Josef Land Archipelago in the high Russian Arctic (80°N) are used to test theoretical reconstructions of the northern margin of the Barents Sea Ice Sheet and constrain Holocene climate changes in this seldom studied region. In agreement with the theoretical reconstructions, the ice sheet probably grounded at the shelf edge in the deep trough to the west of the archipelago. In disagreement with the theoretical reconstructions, deglaciation may have begun in this trough as late as 13,000 14C yr B.P. Foraminiferal assemblages and stable isotopic measurements show that Atlantic-derived intermediate water was present in this trough intermittently during deglaciation, associated with melting of the ice sheet and/or icebergs. The retreating ice-sheet margin reached the present shoreline by 10,300 14C yr B.P. During much of the early and middle Holocene (c. 9400 to c. 4400 14C yr B.P.) local glaciers were behind their present margins, probably due to higher-than-present summer temperatures. Foraminifera in marine sediments further suggest that this period had a relatively high and stable salinity and a longer-than-present summer sea-ice-free season. These foraminifera combined with an interval of absent Bowhead whalebones on the raised beaches show that the longest summer sea-ice-free season occurred between c. 9000 and 7500 14C yr B.P. Subsequently, the duration of the sea-ice-free season decreased and glaciers expanded, reaching near-present margins by c. 2000 14C yr B.P. This Holocene climatic record shows similarities with much of the Eurasian Arctic, suggesting similar climate forcings and responses. Both the Franz Josef Land paleoenvironmental data and global climate model simulations imply that decreasing summer solar radiation was the dominant climate forcing in the Eurasian Arctic during the Holocene. Lesser forcings include changes in Atlantic water inflow to the Arctic, flooding of some of the shallow Eurasian shelves with global sea-level rise, changes in boreal forest cover, and melting of the residual Laurentide Ice Sheet.
