Nd isotope date from Southern Ocean seawater and sediments

We present Nd isotope records from authigenic and detrital phases as well as from foraminifera in four Southern Ocean sediment cores (ODP Site 1091, PS69/607, PS2606, and PS2610). In addition, we include seawater Nd isotope data from station PS118_24 in the Powell Basin. Together, these datasets constrain the spatiotemporal distribution of Antarctic Bottom Water (AABW) in the Atlantic and Indian sectors of the Southern Ocean over the past 32 kyr. The results show that glacial AABW was strongly contracted, with much of the deep Southern Ocean filled by carbon-rich Circumpolar Deep Water derived from the Pacific. During the last deglaciation, AABW expanded in two distinct steps that coincided with Antarctic warming. This expansion promoted Southern Ocean destratification and likely contributed to the contemporaneous rise in atmospheric CO2.