Articles | Volume 13, issue 12
Research article
30 Nov 2017
Research article |  | 30 Nov 2017

Atlantic Water advection vs. glacier dynamics in northern Spitsbergen since early deglaciation

Martin Bartels, Jürgen Titschack, Kirsten Fahl, Rüdiger Stein, Marit-Solveig Seidenkrantz, Claude Hillaire-Marcel, and Dierk Hebbeln

Abstract. Atlantic Water (AW) advection plays an important role in climatic, oceanographic and environmental conditions in the eastern Arctic. Situated along the only deep connection between the Atlantic and the Arctic oceans, the Svalbard Archipelago is an ideal location to reconstruct the past AW advection history and document its linkage with local glacier dynamics, as illustrated in the present study of a 275 cm long sedimentary record from Woodfjorden (northern Spitsbergen; water depth: 171 m) spanning the last  ∼  15 500 years. Sedimentological, micropalaeontological and geochemical analyses were used to reconstruct changes in marine environmental conditions, sea ice cover and glacier activity. Data illustrate a partial break-up of the Svalbard–Barents Sea Ice Sheet from Heinrich Stadial 1 onwards (until  ∼  14.6 ka). During the Bølling–Allerød ( ∼  14.6–12.7 ka), AW penetrated as a bottom water mass into the fjord system and contributed significantly to the destabilization of local glaciers. During the Younger Dryas ( ∼  12.7–11.7 ka), it intruded into intermediate waters while evidence for a glacier advance is lacking. A short-term deepening of the halocline occurred at the very end of this interval. During the early Holocene ( ∼  11.7–7.8 ka), mild conditions led to glacier retreat, a reduced sea ice cover and increasing sea surface temperatures, with a brief interruption during the Preboreal Oscillation ( ∼  11.1–10.8 ka). Due to a  ∼  6000-year gap, the mid-Holocene is not recorded in this sediment core. During the late Holocene ( ∼  1.8–0.4 ka), a slightly reduced AW inflow and lower sea surface temperatures compared to the early Holocene are reconstructed. Glaciers, which previously retreated to the shallower inner parts of the Woodfjorden system, likely advanced during the late Holocene. In particular, topographic control in concert with the reduced summer insolation partly decoupled glacier dynamics from AW advection during this recent interval.

Short summary
Multi-proxy analyses (i.a., benthic foraminiferal assemblages and sedimentary properties) of a marine record from Woodfjorden at the northern Svalbard margin (Norwegian Arctic) illustrate a significant contribution of relatively warm Atlantic water to the destabilization of tidewater glaciers, especially during the deglaciation and early Holocene (until ~ 7800 years ago), whereas its influence on glacier activity has been fading during the last 2 millennia, enabling glacier readvances.