Foraminifera as a proxy for seawater neodymium: Core-top calibration and down-core application for reconstructing Holocene variability in the Indonesian Throughflow (ITF)

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This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This research will assess the utility of Nd-isotopes(defined as εNd) measured in foraminifera as a water mass proxy. The first component of the work is a calibration study that takes advantage of a large set of surface sediments and overlying water samples collected on several cruises worldwide over the past few years to assess the applicability of foraminifera as recorders of deep ocean and thermocline εNd. Rare earth element patterns will be measured on the same samples to test their utility for paleoceanographic research.The new method will then be used to reconstruct Holocene variability in the relative contributions of North Pacific Intermediate Water (NPIW) and South Pacific Water (SPW) to the ITF. Seawater εNd will be measured in three vertical profiles from key locations within the ITF route and south Pacific in order to document the εNd signatures of water masses within the ITF and its end-members. The PIs will generate a low-resolution foraminiferal record of εNd throughout the Holocene in a core located in the Makassar Straits as a proxy for water mass variability, and combine it with measurements of sortable silt mean size as proxy for bottom current velocity. The work will improve understanding of Holocene changes in water mass variability and thermocline flow through the Indonesian Seas. This award supports a postdoctoral researcher.