Radiolarian-based Quaternary palaeoclimate reconstructions of the Sabrina Coast, East Antarctica

Understanding past Southern Ocean climate is important for predicting future climate scenarios. Siliceous microfossil tests preserved in seafloor sediment can be used as proxies to investigate and reconstruct the timing of glacial/interglacial cycles and to estimate past sea-surface temperature. Well-preserved radiolarian tests were sampled from two 2.5 m sediment cores obtained from the continental slope of the Sabrina Coast region, East Antarctica, during RV Investigator voyage IN2017-V01. The radiolarian assemblages were used to verify that the microfossil record can be used as a proxy to reconstruct palaeoclimatic parameters in this region and to estimate summer sea-surface palaeotemperatures using the Imbrie-Kipp transfer function. This research demonstrates that the timing of glacial/interglacial cycles can be identified in Sabrina Coast sediment using the fossil radiolarian record. The Holocene and previous glacial period (i.e. Marine isotope stages 1 and 2) are clearly differentiated with Holocene oceanographic conditions being conducive to biosiliceous sedimentation, whilst conditions during glacial periods are not. Holocene summer sea-surface palaeotemperature estimates range between -3.26 °C and 3.26 °C. Future research will include a Ph.D. project using radiolarians from longer Sabrina Coast cores for palaeoclimate reconstruction over multiple glacial/interglacial cycles.