2026-10-15T09:08:57Z https://oai.datacite.org/oai

doi:10.1594/pangaea.711291 2024-07-20T18:43:33Z PANGAEA PANGAEA.REPOSITORY

Neodymium isotope composition of planktonic foraminifera from ODP Hole 121-758A Burton, Kevin W Vance, Derek PANGAEA 2009 Issued: 2009 doi:10.1016/s0012-821x(00)00011-x Drilling/drill rig Leg121 Joides Resolution Ocean Drilling Program (ODP) This study presents neodymium isotope and elemental data for cleaned planktonic foraminifera from ODP site 758 in the southernmost reaches of the Bay of Bengal in the north-east Indian Ocean. Cleaning experiments using oxidative-reductive techniques suggest that diagenetic Fe-Mn oxyhydroxide coatings can be effectively removed, and that the measured Nd isotope composition reflects the composition of seawater from which the foraminiferal calcium carbonate was precipitated. Modern core-top Pulleniatina obliquiloculata and Globorotalia menardii give epsilon-Nd values of 310.12 +/- 0.16 and 310.28 +/- 0.16, respectively, indistinguishable from recent direct measurements of surface seawater in this area. A high-resolution Nd isotope record obtained from G. menardii for the past 150 kyr shows systematic variations (Delta epsilon-Nd = 3) on glacial-interglacial timescales. The timing of those variations shows a remarkable correspondence with the global oxygen isotope record, which suggests a process controlling the Nd isotope composition that responds in phase with global climate cycles. Palaeoclimate reconstruction indicates that during the last glacial maximum changes in monsoon circulation resulted in a reduction in rainfall over the Indian subcontinent, and a decrease in the flux of river water delivered to the Bay of Bengal. Thus, changes in the riverine input of Nd, a change in either flux or composition, most likely caused the isotope variations, although changes in dust source or local ocean circulation may have also played a role. These results clearly establish a link between climate change and variations in radiogenic isotopes in the oceans, and illustrate the potential of Nd isotopes in foraminifera for highresolution palaeoceanographic reconstruction. Supplement to: Burton, Kevin W; Vance, Derek (2000): Glacial-interglacial variations in the neodymium isotope composition of seawater in the Bay of Bengal recorded by planktonic foraminifera. Earth and Planetary Science Letters, 176(3-4), 425-441 en Collection Supplementary Publication Series of Datasets application/zip Creative Commons Attribution 3.0 Unported https://creativecommons.org/licenses/by/3.0/legalcode