Age determination of sediment core SO75-26KL, Portuguese margin ...

• Main Authors: Zahn, Rainer, Schönfeld, Joachim, Kudrass, Hermann-Rudolph, Park, M-H, Erlenkeuser, Helmut, Grootes, Pieter Meiert
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 1997
• Subjects: Piston corer BGR type; SO75/3; Sonne; North Atlantic
• Online Access: https://dx.doi.org/10.1594/pangaea.734077; https://doi.pangaea.de/10.1594/PANGAEA.734077

A benthic isotope record has been measured for core SO75-26KL from the upper Portuguese margin (1099 m water depth) to monitor the response of thermohaline overturn in the North Atlantic during Heinrich events. Evaluating benthic delta18O in TS diagrams in conjunction with equilibrium deltac fractionation implies that advection of Mediterranean outflow water (MOW) to the upper Portuguese margin was significantly reduced during the last glacial (< 15% compared to 30% today). The benthic isotope record along core SO75-26KL therefore primarily monitors variability of glacial North Atlantic conveyor circulation. The 14C-accelerator mass spectrometry ages of 13.54±.07 and 20.46±.12 ka for two ice-rafted detritus (IRD) layers in the upper core section and an interpolated age of 36.1 ka for a third IRD layer deeper in the core are in the range of published 14C ages for Heinrich events H1, H2, and H4. Marked depletion of benthic delta13C by 0.7-1.1 per mil during the Heinrich events suggests reduced thermohaline ... : Supplement to: Zahn, Rainer; Schönfeld, Joachim; Kudrass, Hermann-Rudolph; Park, M-H; Erlenkeuser, Helmut; Grootes, Pieter Meiert (1997): Thermohaline instability in the North Atlantic during meltwater events: Stable isotope and ice-rafted detritus records from core SO75-26KL, Portuguese margin. Paleoceanography, 12(5), 696-710 ...