Deep circulation changes in the central South Atlantic during the past 145 kyrs reflected in a combined231Pa/230Th, Neodymium isotope and benthic δ13C record

摘要: Abstract Previous work showed that South Atlantic sediments have lower glacial than Holocene 231Pa/230Th, which was attributed to a switch in the flow direction of deep-water. Debate exists, however as degree two processes – circulation and scavenging determine sedimentary making this interpretation contentious. Here we address issue using 145-kyr records paleocirculation proxies. Benthic foraminiferal δ C 13 , neodymium isotopes (eNd) 231Pa/230Th were all measured single sediment core from subtropical gyre. This site largely excludes influence local productivity changes on records. Measured ranges between ∼0.041 during glacials ∼0.055 interglacial periods is consistently production ratio, indicating export 231Pa central for entire duration record. The regionally consistent, suggesting basin-scale oceanographic cause decrease. In turn, less radiogenic eNd benthic confirm classical picture an increase Southern Component Water (SCW) point control observed decrease rather change. We suggest associated with change water mass distribution dominant sink shifted margins and/or Ocean interglacials, North periods. Indeed, elevated deep supports mechanism northward transport by SCW.