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Evidence for an additional Heinrich event between H5 and H6 in the Labrador Sea

2003; American Geophysical Union; Volume: 18; Issue: 4 Linguagem: Inglês

10.1029/2003pa000913

1944-9186

Harunur Rashid, Reinhard Hesse, David J. W. Piper,

Isotope Analysis in Ecology

An additional Heinrich ice‐rafting event is identified between Heinrich events 5 and 6 in eight cores from the Labrador Sea and the northwest Atlantic Ocean. It is characterized by sediment rich in detrital carbonate (40% CaCO 3 ) with high concentration of floating dropstones, high coarse‐fraction (% > 150 μm) content, and has a sharp contact with the underlying but grades into the overlying hemipelagic sediment. It also shows lighter δ 18 O Npl values, indicating freshening due to iceberg rafting and/or meltwater discharge. This event is correlated with Dansgaard‐Oeschger event 14 and interpreted as an additional Heinrich event, H5a. The thickness of H5a in the Labrador Sea reaches up to 220 cm. This additional Heinrich event has also been reported in cores PS2644 and SO82‐5 from the northern North Atlantic. With the recognition of H5a the temporal spacing between Heinrich events 1 to 6 becomes more uniform (∼7 ka).