Piotrowski, A. M.; Noble, T. L.; McCave, I. N. (2011): Reconstructing Southern and Pacific Ocean deep circulation using Nd isotopes. Mineralogical Society, London, United Kingdom, In: Anonymous, Goldschmidt 2011 abstract volume, 75 (3), 1646, georefid:2012-096646

The southwestern Pacific is an important region to reconstruct past ocean circulation since it is the entry point for Southern Ocean waters into the Deep Western Boundary Current of the Pacific. The relationship between deep water neodymium and carbon isotopes in the southwestern Pacific, and their comparison to records from the South Atlantic [1] and Indian Ocean [2], have the potential to provide new information about changes in water mass sourcing and nutrient generation along different deep water flow paths in the Southern Hemisphere [3]. Here we present a new Nd isotope record from ODP Site 1123 on the Chatham Rise (42 S, 172 W, 3.3 km-bsl), and glacial-interglacial Nd isotope changes from Chatham Rise transect of four cores, ranging from 1.4 to 4.8 km-bsl. Nd isotopes were measured by three methods, acid-reductive leaching of bulk detritus, mixed planktonic foraminifera which have authigenic coatings, and those which have been reductively cleaned. The foraminifera with authigenic coatings yield the expected deep seawater Nd isotopic composition, matching nearby water and Fe-Mn nodules measurements, while bulk detrital leachates do not. Reductively cleaned and uncleaned planktonic foraminifera have Nd isotopic compositions within error of each other, suggesting that the host phase of Nd is difficult to remove. The Nd isotopic composition of ODP Site 1123 changes on glacial-interglacial timescales, recording a deglacial Nd isotopic shift from -5 epsilon (sub Nd) during the Last Glacial Maximum (LGM) to -7 epsilon (sub Nd) during the Holocene. The "Pacific-like" Nd isotopic compositions during the LGM suggests reduced Atlantic-sourced water, and is also replicated at the deeper CHAT transect cores. The intermediate depth (1 to 2 km-bsl) cores have a more constant Pacific-like sourcing of waters of -4 epsilon (sub Nd) during the deglaciation. The ODP Site 1123 Nd isotope record appears to track, but is offset from, the South Atlantic [1] and Equatorial Indian Ocean [2] Nd isotope records, suggesting that Atlantic-sector deep water changes are propagated through the Southern Ocean.
West: -171.2956 East: -171.2956 North: -41.4710 South: -41.4710
Expedition: 181
Site: 181-1123
Data access:
Provider: SEDIS Publication Catalogue
Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=2012-096646 (c.f. for more detailed metadata)
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