Reconstructing Atlantic water advection into Rijpfjorden, Northern Svalbard during Holocene

Glacio-marine sediments were retrieved from Northern Nordaustlandet, Svalbard, during an expedition with the R/V Helmer Hanssen in the autumn of 2017. Gravity cores HH17-04-GC and HH17-05-GC were recovered from Rijpfjorden (a poorly studied, remote fjord). The oldest radiocarbon date obtained from HH17-05-GC core is 10.5 cal ka BP. This study analyses variations of Atlantic water advection into Rijpfjorden captured by changes in benthic foraminiferal faunal distribution and in the isotopic composition of calcareous foraminiferal tests during the Holocene. Core HH17-05-GC collected in the inner fjord at a water depth of 217 meters shows glacier-proximal and nearshore Arctic benthic foraminiferal assemblages.Core HH17-04-GC obtained at the mouth of the fjord at a water depth of 273 meters reflects an early appearance of benthic species of foraminifera with more affinity to warmer and more saline water masses. Gravity cores HH17-05-GC and HH17-05-GC show that perennial sea ice quickly decayed and Atlantic water (AW) rapidly resumed its flow across the shelf into the fjord during the early Holocene. Foraminifera faunal assemblages reveal that by 9800 cal ka BP. warmer water foraminifera species dominated the inner fjord. The peak of AW advection occurred between 8900 and 4900 cal ka BP, resulting in warm stable climate and high productivity. A sharp climatic deterioration took place about 4900 cal ka BP, faunal assemblages uncover a drastic decrease of warmer water foraminifera species signaling a reduction of the AW influx into the Arctic basin. Atlantic water advection is the predominant heat transfer mechanism in the northern high latitudes and a key factor in the growth and destabilization of sea ice and intertidal glaciers. A better understanding of the AW advection in Rijpfjorden will contribute to multidisciplinary investigations related to the distribution and decay of sea ice and the oscillation of ocean-atmospheric circulation.