U and Th isotope constraints on the duration of Heinrich events H0-H4 in the southeastern Labrador Sea

• Published in: Paleoceanography
• Main Authors: C. Veiga-Pires, C., Hillaire-Marcel, C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union 1999
• Subjects: Last-glacial-maximum; Atlantic deep-water; Ice-Rafted Debris; North-Atlantic; Boundary undercurrent; Iceberg discharges; Climate-change; Younger dryas; Ocean; Sediments; Hudson; Hudson Strait; Irminger Basin; Orphan Knoll; Labrador Sea; North Atlantic
• Online Access: http://hdl.handle.net/10400.1/11112; https://doi.org/10.1029/1998PA900003

The duration and sequence of events recorded in Heinrich layers at sites near the Hudson Strait source area fbr ice-rafted material are still poorly constrained, notably because of the limit and uncertainties of the C-14 chronology. Here we use high-resolution Th-230-excess measurements, in a 6 m sequence raised from Orphan Knoll (southern Labrador Sea), to constrain the duration of the deposition of the five most recent Heinrich (H) layers. On the basis of maximum/minimum estimates for the mean glacial Th-230-excess flux at the studied site a minimum/maximum duration of 1.0/0.6, 1.4/0.8, 1.3/0.8, 1.5/0.9, and 2.1/1.3 kyr is obtained for H0 (similar to Younger Dryas), H1, H2, H3, and H4, respectively. Thorium-230-excess inventories and other sedimentological features indicate a reduced but still significant lateral sedimentary supply by the Western Boundary Undercurrent during the glacial interval. U and Th series systematics also provide insights into source rocks of H layer sediments (i.e., into distal Irminger Basin/local Labrador Sea supplies). info:eu-repo/semantics/publishedVersion