Neodymium Isotope

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 2580 Experts worldwide ranked by ideXlab platform

Pöppelmeier Frerk - One of the best experts on this subject based on the ideXlab platform.

Gutjahr Marcus - One of the best experts on this subject based on the ideXlab platform.

  • An experimental investigation of the acquisition of Nd by authigenic phases of marine sediments
    'Elsevier BV', 2021
    Co-Authors: Patton, Genna M., Gutjahr Marcus, Frank Martin, Francois Roger, Weis Dominique, Hathorne, Ed C., Gordon Kathy
    Abstract:

    The Neodymium Isotope composition (ɛNd) of authigenic phases in marine sediment is widely used to reconstruct the origin and mixing of water masses of overlying seawater through time. However, at some locations in the modern ocean, the ɛNd of authigenic phases in surface sediment is not consistent with that of local seawater, raising concerns about its current interpretation as a paleotracer of water masses. To further investigate this question, we conducted a laboratory-based incubation experiment with a Mn-oxide phase placed at the sediment–water interface of multicores to assess the extent to which the authigenic phase records seawater ɛNd. Multicores were collected from the Strait of Georgia (SoG), which is a relatively deep coastal waterway with high sedimentation rates, oxygenated surface sediments, and active macrofauna, separating the mainland coast of British Columbia and Vancouver Island. Manganese oxide-coated XAD resin beads were placed at the sediment surface and the cores were incubated for 6 months in a tank filled with SoG seawater spiked with Nd. While the ɛNd of the Mn-oxide coated resin (−4.0) was similar to that of SoG seawater used for the incubation (−3.7), the Nd/Nd of the Mn-oxide phase measured after the incubation indicates that, under our experimental conditions, a minimum of 83% of the Nd associated with the Mn-oxide phase is not sourced from seawater, but from pore water. The Nd/Nd ratio of the Mn-oxide resin is necessary to determine the predominant source of Nd to the resin because the ɛNd of SoG pore water (−3.9) is within analytical error of seawater (−3.7). Using field data and constraints from the Nd mass balance during the incubation, we conclude that the similarity of ɛNd in pore water and seawater in the SoG is fortuitous and not a result of a top-down or bottom-up control. Although the setting of our sediments is not directly comparable to open ocean locations, this study raises concerns about the use of ɛNd in paleocirculation studies, and points to the necessity of elucidating the factors controlling local lithogenic dissolution in pore waters as a prerequisite for the correct interpretation of ɛNd in the authigenic phases of marine sediments

  • Authigenic Neodymium Isotope of IODP Site 306-U1313
    PANGAEA, 2021
    Co-Authors: Pöppelmeier Frerk, Blaser Patrick, Gutjahr Marcus, Schulz Hartmut, Süfke Finn, Lippold Jörg
    Abstract:

    This dataset includes authigenic Fe-Mn oxyhydroxide derived Neodymium (Nd) Isotope data of the North Atlantic IODP site U1313 (Leg 306) from the last glacial (25 - 93 ka). The authigenic sediment phase was extracted by weekly reductive leaching. The Isotope ratios are normalized to 146Nd/144Nd = 0.7219 and were analyzed on a Neptune Plus MC-ICP-MS at GEOMAR, Kiel, Germany. Aim of this study is the reconstruction of the Nd isotopic end member of northern-sourced water over the investigated timespan in order to facilitate reconstructions of the geometry of the Atlantic meridional overturning circulation

  • Holocene Neodymium Isotope data from site M45/5_90
    PANGAEA, 2020
    Co-Authors: Pöppelmeier Frerk, Scheen Jeemijn, Blaser Patrick, Lippold Jörg, Gutjahr Marcus, Stocker, Thomas F
    Abstract:

    This dataset includes authigenic Neodymium Isotope data from deep east Atlantic site M45/5_90 covering the Holocene

  • Holocene Neodymium Isotope data from ODP site 108-662
    PANGAEA, 2020
    Co-Authors: Pöppelmeier Frerk, Scheen Jeemijn, Blaser Patrick, Lippold Jörg, Gutjahr Marcus, Stocker, Thomas F
    Abstract:

    This dataset includes authigenic Neodymium Isotope data from deep east Atlantic ODP site 108-662 covering the Holocene

  • Holocene Neodymium Isotope data from ODP site 108-659
    PANGAEA, 2020
    Co-Authors: Pöppelmeier Frerk, Scheen Jeemijn, Blaser Patrick, Lippold Jörg, Gutjahr Marcus, Stocker, Thomas F
    Abstract:

    This dataset includes authigenic Neodymium Isotope data from deep east Atlantic ODP site 108-659 covering the Holocene

Lippold Jörg - One of the best experts on this subject based on the ideXlab platform.

Alexander M Piotrowski - One of the best experts on this subject based on the ideXlab platform.

  • Antarctic intermediate water circulation in the South Atlantic over the past 25,000 years
    Paleoceanography, 2016
    Co-Authors: Jacob N W Howe, Alexander M Piotrowski, Delia W Oppo, Kuo-fang Huang, Stefan Mulitza, Cristiano Mazur Chiessi, Jurek Blusztajn
    Abstract:

    Antarctic Intermediate Water is an essential limb of the Atlantic meridional overturning circulation that redistributes heat and nutrients within the Atlantic Ocean. Existing reconstructions have yielded conflicting results on the history of Antarctic Intermediate Water penetration into the Atlantic across the most recent glacial termination. In this study we present leachate, foraminiferal, and detrital Neodymium Isotope data from three intermediate-depth cores collected from the southern Brazil margin in the South Atlantic covering the past 25 kyr. These results reveal that strong chemical leaching following decarbonation does not extract past seawater Neodymium composition in this location. The new foraminiferal records reveal no changes in seawater Nd Isotopes during abrupt Northern Hemisphere cold events at these sites. We therefore conclude that there is no evidence for greater incursion of Antarctic Intermediate Water into the South Atlantic during either the Younger Dryas or Heinrich Stadial 1. We do, however, observe more radiogenic Nd Isotope values in the intermediate-depth South Atlantic during the mid-Holocene. This radiogenic excursion coincides with evidence for a southward shift in the Southern Hemisphere westerlies that may have resulted in a greater entrainment of radiogenic Pacific-sourced water during intermediate water production in the Atlantic sector of the Southern Ocean. Our intermediate-depth records show similar values to a deglacial foraminiferal Nd Isotope record from the deep South Atlantic during the Younger Dryas but are clearly distinct during the Last Glacial Maximum and Heinrich Stadial 1, demonstrating that the South Atlantic remained chemically stratified during Heinrich Stadial 1.

  • north atlantic deep water production during the last glacial maximum
    Nature Communications, 2016
    Co-Authors: Jacob N W Howe, Alexander M Piotrowski, Stefan Mulitza, Cristiano Mazur Chiessi, Taryn L Noble, Germain Bayon
    Abstract:

    Changes in deep ocean ventilation are commonly invoked as the primary cause of lower glacial atmospheric CO2. The water mass structure of the glacial deep Atlantic Ocean and the mechanism by which it may have sequestered carbon remain elusive. Here we present Neodymium Isotope measurements from cores throughout the Atlantic that reveal glacial–interglacial changes in water mass distributions. These results demonstrate the sustained production of North Atlantic Deep Water under glacial conditions, indicating that southern-sourced waters were not as spatially extensive during the Last Glacial Maximum as previously believed. We demonstrate that the depleted glacial δ13C values in the deep Atlantic Ocean cannot be explained solely by water mass source changes. A greater amount of respired carbon, therefore, must have been stored in the abyssal Atlantic during the Last Glacial Maximum. We infer that this was achieved by a sluggish deep overturning cell, comprised of well-mixed northern- and southern-sourced waters.

  • oscillating glacial northern and southern deep water formation from combined Neodymium and carbon Isotopes
    Earth and Planetary Science Letters, 2008
    Co-Authors: Alexander M Piotrowski, Hemming R Sidney, Richard G Fairbanks, David R Zylberberg
    Abstract:

    Abstract While ocean circulation is driven by the formation of deep water in the North Atlantic and the Circum-Antarctic, the role of southern-sourced deep water formation in climate change is poorly understood. Here we address the balance of northern- and southern-sourced waters in the South Atlantic through the last glacial period using Neodymium Isotope ratios of authigenic ferromanganese oxides in thirteen deep sea cores from throughout the South Atlantic. The data indicate that northern-sourced water did not reach the Southern Ocean during the late glacial, and was replaced by southern-derived intermediate and deep waters. The high-resolution Neodymium Isotope record (~ 300 yr sample spacing) from two spliced deep Cape Basin sites indicates that over the last glacial period northern-sourced water mass export to the Southern Ocean was stronger during the major Greenland millennial warming intervals (and Southern Hemisphere cool periods), and particularly during the major interstadials 8, 12, and 14. Northern-sourced water mass export was weaker during Greenland stadials and reached minima during Heinrich Events. The benthic foraminiferal carbon Isotopes in the same Cape Basin core reflect a partial control by Southern Hemisphere climate changes and indicate that deep water formation and ventilation occurred in the Southern Ocean during major Greenland cooling intervals (stadials). Together, Neodymium Isotopes and benthic carbon Isotopes provide new information about water mass sourcing and circulation in deep Southern Ocean waters during rapid glacial climate changes. Combining carbon and Neodymium Isotopes can be used to monitor the relative proportion of northern- and southern-sourced waters in the Cape Basin to gain insight into the processes which control the carbon isotopic composition of deep waters. In this study we show that deep water formation and circulation was more important than biological productivity and nutrient regeneration changes for controlling the carbon Isotope chemistry of Antarctic Bottom Water during millennial-scale glacial climate cycles. This observation also lends support to the hypothesis that ocean circulation is linked to interhemispheric climate changes on short timescales, and that ventilation in the glacial ocean rapidly switched between the northern and Southern Hemisphere on millennial timescales.

  • intensification and variability of ocean thermohaline circulation through the last deglaciation
    Earth and Planetary Science Letters, 2004
    Co-Authors: Alexander M Piotrowski, Steven L Goldstein, Sidney R Hemming, Richard G Fairbanks
    Abstract:

    Neodymium Isotope ratios in the authigenic ferromanganese oxide component in a southeastern Atlantic core reveal a history of the global overturning circulation intensity through the last deglaciation. From a minimum during the Last Glacial Maximum (LGM), North Atlantic Deep Water (NADW) began to strengthen between 18 and 17 kyr cal. BP, approximately 2000–3000 years before the Bolling warming. It exhibits a gradually increasing baseline intensity that plateaus in the early Holocene, tracks increasing Northern Hemisphere insolation and parallels atmospheric CO2 concentration. Millennial-scale fluctuations are superimposed on this baseline NADW increase, corresponding to events in Northern Hemisphere climate records. The millennial excursions show sharp increases associated with the pre-Bolling retreat of continental glaciers and the Bolling warming itself, a decrease with Allerod cooling, and a recovery through the Younger Dryas and early Holocene. The data confirm a close link between deep-ocean circulation and North Atlantic climate changes. There is no clear linkage with meltwater pulses, indicating that rapid meltwater additions did not trigger observable mode changes in NADW production. However, rapid changes in North Atlantic sea ice cover show a strong relationship with the millennial perturbations of NADW flux to the deep Southern Ocean. The data indicate that the baseline intensity of NADW reaching the Cape Basin is paced by Northern Hemisphere insolation and that North Atlantic sea ice coverage acts as a major amplifying link between the oceans and the atmosphere. D 2004 Elsevier B.V. All rights reserved.

Germain Bayon - One of the best experts on this subject based on the ideXlab platform.

  • Rare earth element and Neodymium Isotope tracing of sedimentary rock weathering
    Chemical Geology, 2020
    Co-Authors: Germain Bayon, Thibault Lambert, Nathalie Vigier, Patrick De Deckker, Nicolas Freslon, Kwangchul Jang, Christina Larkin, Alexander Piotrowski, Kazuyo Tachikawa, Maude Thollon
    Abstract:

    Chemical weathering plays an important role in sequestering atmospheric CO2, but its potential influence onglobal climate over geological timescales remains debated. To some extent, this uncertainty arises from thedifficulty in separating the respective contribution of sedimentary and crystalline silicate rocks to past weath-ering rates in the geological record; two types of rocks having presumably different impact on the long-termcarbon cycle. In this study, we investigate the use of rare earth element (REE) and Neodymium Isotopes (εNd)inleached iron oxide fractions of river sediments for tracing the origin of weathered rocks on continents. A newindex, called‘concavity index’(CI), is defined for measuring the degree of mid-REE enrichment in geologicalsamples, which enables the determination of the source of iron oxides in sediments, such as seawater-derived Fe-oxyhydroxide phases, ancient marine Fe oxides derived from the erosion of sedimentary rocks, and recentsecondary oxides formed in soils via alteration of crystalline silicate rocks or pyrite oxidation. Using this index,we demonstrate that theεNddifference between paired Fe-oxide and detrital fractions in river sediments (definedhere asΔεNd Feox-Det) directly reflects the relative contribution of sedimentary versus crystalline silicate rocksduring weathering. While rivers draining old cratons and volcanic provinces display near-zeroΔεNd Feox-Detvalues indicative of dominant silicate weathering (0.5 ± 1.1;n= 30), multi-lithological catchments hostingsedimentary formations yield systematically higher values (2.7 ± 1.2;n= 44), showing that sedimentary rockweathering can be traced by the occurrence of riverine Fe oxides having more radiogenic Nd Isotope signaturescompared to detrital fractions. This assumption is reinforced by the evidence that calculatedΔεNd Feox-Detvaluesagree well with previous estimates for carbonate and silicate weathering rates in large river basins.Examining the influence of climate and tectonics on measured Nd isotopic compositions, wefind thatΔεNdFeox-Detis strongly dependent on temperature in lowlands, following an Arrhenius-like relationship that reflectsenhanced alteration of silicate rocks and formation of secondary Fe oxides in warmer climates. In contrast, inhigh-elevation catchments,ΔεNd Feox-Detdefines striking correlation with maximum basin elevation, which wealso interpret as reflecting the intensification of silicate weathering and associated Fe oxide formation as ele-vation decreases, due to the combined effects of thicker soils and warmer temperature.Overall, our newfindings are consistent with previous assertions that the alteration of sedimentary rocksprevails in high-elevation environments, while silicate weathering dominates infloodplains. This novel approachcombining REE and Nd Isotopes opens new perspectives for disentangling the weathering signals of sedimentaryand crystalline silicate rocks in the geologic record, which could be used in future studies to reassess the causalrelationships between mountain uplift, erosion and climate throughout Earth's history.

  • north atlantic deep water production during the last glacial maximum
    Nature Communications, 2016
    Co-Authors: Jacob N W Howe, Alexander M Piotrowski, Stefan Mulitza, Cristiano Mazur Chiessi, Taryn L Noble, Germain Bayon
    Abstract:

    Changes in deep ocean ventilation are commonly invoked as the primary cause of lower glacial atmospheric CO2. The water mass structure of the glacial deep Atlantic Ocean and the mechanism by which it may have sequestered carbon remain elusive. Here we present Neodymium Isotope measurements from cores throughout the Atlantic that reveal glacial–interglacial changes in water mass distributions. These results demonstrate the sustained production of North Atlantic Deep Water under glacial conditions, indicating that southern-sourced waters were not as spatially extensive during the Last Glacial Maximum as previously believed. We demonstrate that the depleted glacial δ13C values in the deep Atlantic Ocean cannot be explained solely by water mass source changes. A greater amount of respired carbon, therefore, must have been stored in the abyssal Atlantic during the Last Glacial Maximum. We infer that this was achieved by a sluggish deep overturning cell, comprised of well-mixed northern- and southern-sourced waters.

Related terms

Neodymium Isotope - 15 days free trial to Access Experts & Abstracts