Evolution of the Global Overturning Circulation since the Last Glacial Maximum based on marine authigenic neodymium isotopes ...

The Global Overturning Circulation is linked to climate change on glacial-interglacial and multi-millennial timescales. The understanding of past climate-circulation links remains hindered by apparent conflicts among proxy measures of circulation. Here we reconstruct circulation changes since the La...

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Bibliographic Details
Main Authors: Du, Jianghui, Haley, Brian A., Mix, Alan C.
Format: Text
Language:English
Published: ETH Zurich 2020
Subjects:
Ocean circulation
Last glacial maximum
Last deglaciation
Paleoceanography
Paleoclimate
Neodymium isotopes
Marine Nd Cycle
Authigenic phase
Detrital sediments
North Atlantic
Online Access:https://dx.doi.org/10.3929/ethz-b-000423888
http://hdl.handle.net/20.500.11850/423888
Description
Summary:The Global Overturning Circulation is linked to climate change on glacial-interglacial and multi-millennial timescales. The understanding of past climate-circulation links remains hindered by apparent conflicts among proxy measures of circulation. Here we reconstruct circulation changes since the Last Glacial Maximum (LGM) based on a global synthesis of authigenic neodymium isotope records (εNd). We propose the bottom-up framework of interpreting seawater and authigenic εNd considering not only conservative watermass mixing, but also the preformed properties and the non-conservative behavior of εNd, both subject to sedimentary influences. We extract the major spatial-temporal modes of authigenic εNd using Principal Component Analysis, and make a first-order circulation reconstruction with budget-constrained box model simulations. We show that during the LGM, the source region of North Atlantic overturning shifted southward, which led to more radiogenic preformed εNd of glacial Northern Source Water (NSW). ... : Quaternary Science Reviews, 241 ...

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