Physical properties of sediment cores from the Labrador Sea

• Main Authors: Weber, Michael E, Mayer, Larry A, Hillaire-Marcel, Claude, Bilodeau, G, Rack, Frank R, Hiscott, Richard N, Aksu, Ali E
• Format: Dataset
• Language: English
• Published: PANGAEA 2001
• Subjects: 45F; CALYPSO; Calypso Corer; Fogo Sea Mount; Greenland Rise; IMAGES; IMAGES I; IMAGES V; International Marine Global Change Study; Laurentian fan; Marion Dufresne (1995); MD101; MD114; MD952024; MD95-2024; MD952025; MD95-2025; MD952026; MD95-2026; MD952028; MD95-2028; MD952029; MD95-2029; MD952031; MD95-2031; MD952033; MD95-2033; MD99-2242; Narwhal; Orphan Knoll; Sackville spur; upper Laurentien Island; Fogo; Greenland; Hudson; Hudson Strait; Labrador Sea; narwhal*; Neogloboquadrina pachyderma; North Atlantic Deep Water; North Atlantic
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.778950; https://doi.org/10.1594/PANGAEA.778950

Sediment core logs from six sediment cores in the Labrador Sea show millennial-scale climate variability during the last glacial by recording all Heinrich events and several major Dansgaard-Oeschger cycles. The same millennial-scale climate change is documented for surface-water d18O records of Neogloboquadrina pachyderma (left coiled); hence the surface-water d18O record can be derived from sediment core logging by means of multiple linear regression, providing a paleoclimate proxy record at very high temporal resolution (70 yrs). For the Labrador Sea, sediment core logs contain important information about deep-water current velocities and also reflect the variable input of IRD from different sources as inferred from grain-size analysis, benthic d18O, the relation of density and p-wave velocity, and magnetic susceptibility. For the last glacial, faster deep-water currents which correspond to highs in sediment physical properties, occurred during iceberg discharge and lasted for a several centuries to a few millennia. Those enhanced currents might have contributed to increased production of intermediate waters during times of reduced production of North Atlantic Deep Water. Hudson Strait might have acted as a major supplier of detrital carbonate only during lowered sea level (greater ice extent). During coldest atmospheric temperatures over Greenland, deep-water currents increased during iceberg discharge in the Labrador Sea, then surface water freshened shortly after, while the abrupt atmospheric temperature rise happened after a larger time lag of >=1 kyr. The correlation implies a strong link and common forcing for atmosphere, sea surface, and deep water during the last glacial at millennial time scales but decoupling at orbital time scales.