Late Pleistocene to holocene palaeoclimates and palaeoenvironments inferred from palynofacies and dinoflagellates cysts in Santos Basin, offshore Brazil

We analyse Late Pleistocene to Holocene palynofacies and dinoflagellates in a sedimentary core (PC PRIMA 4), collected on the northern offshore shelf of the Santos Basin of Brazil, which covers the last 29,429 cal yrs BP. The aim of this study is to better understand changes in climate and oceanographic circulation that affected this region since the Last Glacial Maximum (LGM), and the 120 m rise in sea level that followed. The organic matter in the core shows characteristics consistent with an oxygenized proximal shelf with incursions of continental elements, which evolved into a more distal dysaerobic-anoxic environment over the studied time interval. An increase in phytoclast (opaque and non-opaque) abundance during the Last Glacial Maximum interval suggests enhanced river supply, driven by the increase in the hydrological cycle resulting from cold and humid climatic conditions. The increase of Amorphous Organic Matter from 16,437 cal yrs BP suggests the onset of anoxic bottomwater conditions that resulted of an increase in water depth. Together with the percentage increase of Operculodinium centrocarpum and the fall in Tuberculodinium vancampoae abundance, this implies the postglacial development of warmer currents. In summary, our results better document the climatic and oceanographic changes that occurred in this area during and following the LGM.