Boundary Sources and Sink of 230Th, 232Th, and 231Pa n the NW Pacific

Lead PI: Dr. Robert F. Anderson , Mr. Martin Q. Fleisher

Unit Affiliation: Geochemistry, Lamont-Doherty Earth Observatory (LDEO)

September 2010 - August 2013
Pacific Ocean
Project Type: Research

DESCRIPTION: The proposal will address the new body of evidence that suggests spatial variability in the chemical fractionation between Th and Pa may influence sedimentary 231Pa/230Th ratios as much as or more than enhanced scavenging at margins by measuring concentration profiles of dissolved 230Th, 232Th, and 231Pa in samples from seven stations in the North Pacific Ocean.

OUTCOMES: Found that dissolved 230Th distributions are consistent with expectations from reversible scavenging but not with boundary scavenging theory. It is believed this is due to different biogeochemical processes in two different gyres, suggesting that marine ecosystems play a larger role in regulating scavenging. Also found that comparing 230Th with 232Th can quantify the supply of other trace elements.