4 High latitude paleoceanographic discoveries from Scientific Ocean Drilling (IODP, ODP, DSDP)

Scientific Ocean Drilling has retrieved thousands of meters of sediment cores from the high latitude oceans.  This session provides the opportunity to present the results of work to understand Cenozoic climate and oceanographic changes.

Sunday, 22 March 2026
8:00 AM - 12:00 PM
CCC, Room 27

Five Million Years of North Atlantic Deep Water Flow Variability from IODP Site U1564, Gardar Drift

Paper number: 4-4
Program: Technical Sessions
Time: 9:05 AM – 9:25 AM

Authors

Abstract

North Atlantic Deep Water (NADW) is a key component of the Atlantic Meridional Overturning Circulation (AMOC), and its variability influences the distribution of heat and tracers in the North Atlantic. A major pathway of NADW export is the Iceland–Scotland Overflow Water (ISOW), which flows along the Gardar Drift on the eastern flank of the Reykjanes Ridge. Despite its climatic importance, the long-term behavior of ISOW remains incompletely constrained.

Here, we present a ~5 Ma reconstruction of ISOW variability using sediment cores from IODP Expedition 395, Site U1564 (59.9°N, 23.3°W; 2208 m water depth) on the Gardar Drift. Our multi-proxy approach integrates discrete wavelength-dispersive XRF (WDXRF) measurements and sortable silt (SS) grain-size data with high-resolution XRF core-scanner measurements. WDXRF data calibrate the scanner record via multivariate log-ratio transformation, and SS measurements are used to convert ln(Zr/Rb) ratios to relative bottom-current velocities.

This high-resolution, near-continuous record reveals coherent shifts in ISOW strength across major Plio-Pleistocene climate transitions, including intervals of both enhanced and reduced bottom-current flow. These results refine our understanding of deep-water export from the Nordic Seas and offer new constraints on long-term AMOC variability.

Geological Society of America Abstracts with Programs. Vol. 58, No. 2

doi: 10.1130/abs/2026NE-411295

© Copyright 2026 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.