Rare earth elements and Neodymium isotopic analysis from ODP Site 130-807

DOI

This study reports neodymium isotopic (e-Nd) variability at a time resolution of 0.5 to 3 Ma since the Late Cretaceous as recorded in a marine sedimentary core from the Western Pacific (ODP 807; 3°36'N, 156°3?E; Ontong Java Plateau). Our core is mainly fine-grained and composed of continuous sequences of nannofossil oozes. The e-Nd measured in the carbonate fraction was used as a proxy of e-Nd of seawater of the Western Pacific. On a long term, our results indicate a general increase in e-Nd of seawater by 4.5 e-Nd units from the Late Cretaceous (e-Nd = - 6) to modern times (e-Nd = - 1.7). This pattern was related to the emergence of the West Pacific margin and the progressive isolation of the Pacific Ocean from the other oceanic basins, resulting in its progressive shift to more radiogenic values through the Cenozoic. This long-term pattern is in accordance with previously published Fe-Mn crusts data from the same study area. Nonetheless, by being at higher time resolution, our data records additional sharp and pseudo-cyclic variations (~ 7?11 Ma periods) superimposed on this long-term pattern from ~ 40 Ma to modern times. These oscillations might reflect the alternating dominance of the two main deep water masses (NPDW and UCDW) bathing our study area. In the same core, we also measured the e-Nd in the detrital fraction in order to trace back the local terrigenous inputs. The terrigenous record shows a significant variability up to + 12 e-Nd units. This was linked to the emergence of the west Pacific subduction zone ~ 50 Ma ago causing a higher input of radiogenic isotopes. In conclusion, the large variability observed in both seawater and detrital e-Nd records most probably result from a major tectonic and oceanic circulation reorganization of the Pacific Ocean.

Supplement to: Le Houedec, Sandrine; Meynadier, Laure M; Allègre, Claude J (2016): Seawater Nd isotope variation in the Western Pacific Ocean since 80Ma (ODP 807, Ontong Java Plateau). Marine Geology, 380, 138-147

Identifier
DOI https://doi.org/10.1594/PANGAEA.871963
Related Identifier https://doi.org/10.1016/j.margeo.2016.07.005
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.871963
Provenance
Creator Le Houedec, Sandrine ORCID logo; Meynadier, Laure M; Allègre, Claude J
Publisher PANGAEA
Publication Year 2017
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Language English
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 2 datasets
Discipline Earth System Research
Spatial Coverage (156.625 LON, 3.607 LAT)
Temporal Coverage Begin 1990-02-26T00:00:00Z
Temporal Coverage End 1990-03-02T00:00:00Z