(Table 1) Age determination of sediment cores CH07-98-22 and KNR140-2-59

Western subtropical North Atlantic oceanic and atmospheric circulations connect tropical and subpolar climates. Variations in these circulations can generate regional climate anomalies that are not reflected in Northern Hemisphere averages. Assessing the significance of anthropogenic climate change...

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Bibliographic Details
Main Authors: Saenger, Casey, Came, Rosemarie E, Oppo, Delia W, Keigwin, Lloyd D, Cohen, Anne L
Format: Dataset
Language:English
Published: PANGAEA 2011
Subjects:
Age
14C AMS
14C milieu/reservoir corrected
comment
dated
dated material
dated standard deviation
Calendar age
standard deviation
CH07-98-22
Depth
bottom/max
sediment/rock
top/min
Event label
GGC
Giant gravity corer
Knorr
KNR140
KNR140-2-59
Laboratory code/label
MUC
MultiCorer
North Atlantic
North Atlantic oscillation
Online Access:https://doi.pangaea.de/10.1594/PANGAEA.830724
https://doi.org/10.1594/PANGAEA.830724
Description
Summary:Western subtropical North Atlantic oceanic and atmospheric circulations connect tropical and subpolar climates. Variations in these circulations can generate regional climate anomalies that are not reflected in Northern Hemisphere averages. Assessing the significance of anthropogenic climate change at regional scales requires proxy records that allow recent trends to be interpreted in the context of long-term regional variability. We present reconstructions of Gulf Stream sea surface temperature (SST) and hydrographic variability during the past two millennia based on the magnesium/calcium ratio and oxygen isotopic composition of planktic foraminifera preserved in two western subtropical North Atlantic sediment cores. Reconstructed SST suggests low-frequency variability of ~1°C during an interval that includes the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA). A warm interval near 1250 A.D. is distinct from regional and hemispheric temperature, possibly reflecting regional variations in ocean-atmosphere heat flux associated with changes in atmospheric circulation (e.g., the North Atlantic Oscillation) or the Atlantic Meridional Overturning Circulation. Seawater d18O, which is marked by a fresher MCA and a more saline LIA, covaries with meridional migrations of the Atlantic Intertropical Convergence Zone. The northward advection of tropical salinity anomalies by mean surface currents provides a plausible mechanism linking Carolina Slope and tropical Atlantic hydrology.

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