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dc.contributor.authorHayes, Christopher T.  Concept link
dc.contributor.authorAnderson, Robert F.  Concept link
dc.contributor.authorFleisher, Martin Q.  Concept link
dc.contributor.authorHuang, Kuo-Fang  Concept link
dc.contributor.authorRobinson, Laura F.  Concept link
dc.contributor.authorLu, Yanbin  Concept link
dc.contributor.authorCheng, Hai  Concept link
dc.contributor.authorEdwards, R. Lawrence  Concept link
dc.contributor.authorMoran, S. Bradley  Concept link
dc.date.accessioned2015-07-09T19:45:32Z
dc.date.available2015-07-09T19:45:32Z
dc.date.issued2014-07
dc.identifier.urihttps://hdl.handle.net/1912/7377
dc.descriptionAuthor Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part II: Topical Studies in Oceanography 116 (2015): 29-41, doi:10.1016/j.dsr2.2014.07.007.en_US
dc.description.abstractThe long-lived uranium decay products 230Th and 231Pa are widely used as quantitative tracers of adsorption to sinking particles (scavenging) in the ocean by exploiting the principles of radioactive disequilibria. Because of their preservation in the Pleistocene sediment record and through largely untested assumptions about their chemical behavior in the water column, the two radionuclides have also been used as proxies for a variety of chemical fluxes in the past ocean. This includes the vertical flux of particulate matter to the seafloor, the lateral flux of insoluble elements to continental margins (boundary scavenging), and the southward flux of water out of the deep North Atlantic. In a section of unprecedented vertical and zonal resolution, the distributions of 230Th and 231Pa across the North Atlantic shed light on the marine cycling of these radionuclides and further inform their use as tracers of chemical flux. Enhanced scavenging intensities are observed in benthic layers of resuspended sediments on the eastern and western margins and in a hydrothermal plume emanating from the Mid-Atlantic Ridge. Boundary scavenging is clearly expressed in the water column along a transect between Mauritania and Cape Verde which is used to quantify a bias in sediment fluxes calculated using 230Th-normalization and to demonstrate enhanced 231Pa removal from the deep North Atlantic by this mechanism. The influence of deep ocean ventilation that leads to the southward export of 231Pa is apparent. The 231Pa/230Th ratio, however, predominantly reflects spatial variability in scavenging intensity, complicating its applicability as a proxy for the Atlantic meridional overturning circulation.en_US
dc.description.sponsorshipFunding for ship time, sampling operations, and hydrographic 552 data was provided by the U. S. National Science Foundation to the US GEOTRACES North Atlantic Transect Management team of W. Jenkins (OCE-0926423), E. Boyle (OCE-0926204), and G. Cutter (OCE-0926092). Radionuclide studies were supported by NSF (OCE-0927064 to L-DEO, OCE-0926860 to WHOI, OCE-0927757 to URI, and OCE-0927754 to UMN). LFR was also supported by Marie Curie Reintegration Grant and the European Research Council.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.relation.urihttps://doi.org/10.1016/j.dsr2.2014.07.007
dc.subjectGEOTRACESen_US
dc.subjectNorth Atlantic Oceanen_US
dc.subjectThoriumen_US
dc.subjectProtactiniumen_US
dc.subjectScavengingen_US
dc.subjectVentilationen_US
dc.titleTh-230 and Pa-231 on GEOTRACES GA03, the US GEOTRACES North Atlantic transect, and implications for modern and paleoceanographic chemical fluxesen_US
dc.typePreprinten_US


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