Distribution of 230Th in the Labrador Sea and its relation to ventilation

Measurements of dissolved and particulate230Th and232Th by thermal ionization mass spectrometry were made on samples collected from the Labrador Sea and the Denmark Strait and Iceland-Scotland overflow waters. The large-scale feature of low and invariant230Th evident in deep waters of the Labrador Sea and previously observed in the deep northern Atlantic can be reproduced using a reversible scavenging model that includes the effect of ventilation. Advective transport also must be important in the redistribution of230Th in other regions of the Atlantic and for other long-lived tracers, such as231Pa,26Al and10Be.