Description: The Plio-Pleistocene intensification of Northern Hemisphere continental ice-sheet development is known to have profoundly affected the global climate system. Evidence for early continental glaciation is preserved in sediments throughout the North Atlantic Ocean, where ice-rafted detritus (IRD) layers attest to the calving of sediment-loaded icebergs from circum-Atlantic ice sheets. So far, Early-Pleistocene IRD deposition has been attributed to the presence of high-latitudinal ice sheets, whereas the existence and extent of ice accumulation in more temperate, mid-latitudinal regions remains enigmatic. Here we present results from the multiproxy provenance analysis of a unique, Pleistocene-Holocene IRD sequence from the Irish NE Atlantic continental margin. There, the Challenger coral carbonate mound (IODP Expedition 307 site U1317) preserved an Early-Pleistocene record of 16 distinctive IRD events, deposited between ca 2.6 and 1.7 Ma. Strong and complex IRD signals are also identified during the mid-Pleistocene climate transition (ca 1.2 to 0.65 Ma) and throughout the Middle-Late Pleistocene interval. Radiogenic isotope source-fingerprinting, in combination with coarse lithic component analysis, indicates a dominant sediment source in the nearby British-Irish Isles, even for the oldest, Early-Pleistocene IRD deposits. Hence, our findings demonstrate, for the first time, repeated and substantial (i.e. marine-terminating) ice accumulation on the British-Irish Isles since the beginning of the Pleistocene. Contemporaneous expansion of both high- and mid-latitudinal ice sheets in the North Atlantic region is therefore implied at the onset of the Pleistocene. Moreover, it suggests the recurrent establishment of (climatically) favourable conditions for ice sheet inception, growth and instability in mid-latitudinal regions, even in the earliest stages of Northern Hemisphere glacial expansion and in an obliquity-driven climate system.

Description: Presence-absence records for four cold-water coral (CWC) taxa (Enallopsammia rostrata, Acanella arbuscula, Metallogorgia spp. and Paramuricea spp.) were gathered to conduct distribution models on seamounts (Cadamosto, Nola, Senghor and Cabo Verde) of the Cabo Verde archipelago (NW Africa), covering a bathymetric range from 2100 to 750 m water depth. Data were extracted from video footage collected with Remotely Operated Vehicles during the M80/3 Meteor (2010) and the iMirabilis2 (2021) research expeditions. Video data from the iMirabilis2 expedition was analysed, quantitively, using the open-source software BIIGLE (Langenkämper et al. 2017). Observations from five continuous 1 to 2 km-long video transects between 2000 and 1400 m depth at Cadamosto Seamount were converted into presence-absence data points. Similar data were not available for the seamounts explored during M80/3 Meteor. However, all the available images and short video clips from that expedition were analysed to identify presence and absence points for each of the four target CWC taxa. All the available presence/absence data from the two expeditions was transformed into one point per grid cell of a 100 m resolution bathymetry grid, with the prevalence of the presence records over the absence records, in grid cells where both categories overlapped.