Wahlenbergfjord, eastern Svalbard: a glacier-surrounded fjord reflecting regional hydrographic variability during the Holocene?

Exceptionally high sedimentation rates in Arctic fjords provide the possibility to reconstruct environmental conditions in high temporal resolution during the (pre-)Holocene. The unique geographical location of Svalbard at the intersection of Arctic and Atlantic waters offers the opportunity to estimate local (mainly glacier-related) vs. regional (hydrographic) variabilities. Sedimentological, micropalaeontological and geochemical data from the very remote, glacier-surrounded Wahlenbergfjord in eastern Svalbard provides information on glacier dynamics, palaeoceanographic and sea-ice conditions during the Holocene. The present study illustrates a high meltwater discharge during the summer insolation maximum (c.11.3-7.7 ka) when the intrusion of upwelled relatively warm Atlantic-derived waters led to an almost open fjord situation with reduced sea ice in summer. Around 7.7 ka, a rapid hydrographic shift occurred: the dominance of inflowing Atlantic-derived waters was replaced by a stronger influence of Arctic Water reflecting regional palaeoceanographic conditions evident in the benthic foraminiferal fauna also at Svalbard's margins. Neoglacial conditions characterized the late Holocene (c.3.1-0.2 ka), when glaciers probably advanced as cold atmospheric temperatures were decoupled from the advection of relatively warm intermediate waters probably caused by an extending sea-ice coverage. Accordingly, our data show that even a remote, glacier-proximal study site reflects rapid as well as longer-term regional changes.