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

• 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

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 ...