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. The number of sedimentary records collected along theBrazilian continental margin has increased significantly in recent years,but relatively few are located in shallow waters and registerpaleoceanographic processes in the outer shelf–middle slope prior to 10–15 ka. For instance, the northward flow up to 23–24∘ S ofcold and fresh shelf waters sourced from the Subantarctic region is animportant feature of current hydrodynamics in the subtropical western SouthAtlantic Ocean, and yet limited information is available for the long-termchanges of this system. Herein, we considered a suite of organic andinorganic proxies – alkenones-derived sea surface temperature (SST),δD-alkenones, δ18O of planktonic foraminifera, andice-volume free seawater δ18OIVF−SW – in sediment fromtwo cores (RJ-1501 and RJ-1502) collected off the Rio de Janeiro Shelf (SEBrazilian continental shelf) to shed light on SST patterns and relativesalinity variations since the end of the last glacial cycle in the regionand the implications of these processes over a broader spatial scale. Thedata indicate that, despite the proximity (∼40 km apart) ofboth cores, apparently contradictory climatic evolution occurred at the twosites, with the shallower (deeper) core RJ-1501 (RJ-1502) showingconsistently cold (warm) and fresh (salt) conditions toward the Last Glacial Maximum (LGM) and last deglaciation. This can be reconciled by considering that the RJ-1501 core registered a signal from mid- to high latitudes on the upper slope off Rio de Janeiro represented by the influence of the cold and fresh waters composed of Subantarctic Shelf Water and La Plata Plume Water transported northward by the Brazilian Coastal Current (BCC). The data from core RJ-1502 and previous information for deep-cores from the same regionsupport this interpretation. In addition, alkenone-derived SST and δ18OIVF−SW suggest a steep thermal and density gradient formedbetween the BCC and Brazil Current (BC) during the last climate transitionwhich, in turn, may have generated perturbations in the air–sea heat fluxwith consequences for the regional climate of SE South America. In ascenario of future weakening of the Atlantic Meridional OverturningCirculation, the reconstructed gradient may become a prominent feature ofthe region.

Contrasting late-glacial paleoceanographic evolution between the upper and lower continental slope of the western South Atlantic