Ricarda Dziadek¹, Karsten Gohl¹, Norbert Kaul²

¹Alfred Wegener Institute – Helmholtz Centre For Polar And Marine Research, Bremerhaven, Germany, ²University of Bremen, Department of Geosciences, Bremen, Germany

Due to a complex tectonic and magmatic history of West Antarctica, the region is suspected to exhibit strong heterogeneous geothermal heat flux variations. Although the maximum ice extent has retreated from the shelf since the last glacial maximum, the trends of offshore GHF patterns and the overall order of magnitude are hypothetically related to those areas onshore where the West Antarctic Ice Sheet (WAIS) rests on geologically related structures. High-resolution GHF will aid the understanding of the paleo-retreat of the ice sheet in the Amundsen Sea Sector. This presentation builds on our previous studies in which we discussed geothermal heat flux based on 26 in-situ temperature measurements that were conducted in 2010 in the Amundsen Sea Embayment (ASE) in West Antarctica. We found, that the shallow (3 m) in-situ temperature measurements were likely influenced by inter-annual bottom-water temperature variability, leading to GHF estimates biased towards lower values (mean = 33 mWm-²). During RV Polarstern expedition PS104 in early 2017 we collected additional 28 in-situ temperature measurements in marine sediments (11 m) for deriving geothermal heat flux in the ASE, which will overall improve the spatial coverage of this region. Furthermore, we monitored the vertical temperature profile of the water column at these stations, which allows to map Circumpolar Deep Water (CDW) distributions across the inner Pine Island Shelf with greater detail.