Research Spotlight: Interpreting 231Pa/230Th observations and changes in ocean circulation



[1] Understanding past changes in ocean circulation is important, because the ocean transports heat and changes in ocean circulation can affect climate. To better understand past ocean circulation changes, some researchers have used the ratio of two isotopes, protactinium-231 (231Pa) and thorium-230 (230Th), in sediments as a proxy to infer changes in the Atlantic meridional overturning circulation (AMOC). Some studies have suggested that AMOC during the climate fluctuations of the Last Glacial Maximum (LGM; ∼21,000–18,000 years ago) and Heinrich Event 1 (H1; ∼17,000–15,000 years ago) was different from modern AMOC.