Lead isotopes of feldspar in North Atlantic Ocean sediments ...

• Main Authors: Gwiazda, Roberto H, Hemming, Sidney R, Broecker, Wallace S
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 1996
• Subjects: Hudson Bay; Ice Sheet; Labrador Sea; North Atlantic
• Online Access: https://dx.doi.org/10.1594/pangaea.786112; https://doi.pangaea.de/10.1594/PANGAEA.786112

The provenance of ice-rafted debris (IRD) deposited in the North Atlantic before, during, and after Heinrich event 2 has been determined through measuring the lead isotopic composition of single feldspar grains and multiple-grain composites from the larger than 150-µm size fraction, from cores from the eastern and western North Atlantic and from the Labrador Sea. Single-grain analyses are used to identify the specific continental sources of the IRD, whereas composite samples are used to assess the relative IRD contributions from different sources. All single grains from Heinrich layer 2 (H 2) as well as H 2 composites plot along a correlation line on a 207Pb/204Pb versus 206Pb/204Pb diagram characteristic of the Churchill province of the Canadian shield. This is yet another strong piece of evidence that this Heinrich event was dominated by a massive iceberg discharge of the Laurentide ice sheet lobe located over Hudson Bay. In contrast, single grains from the ambient glacial sediment (above and below H 2) ... : Supplement to: Gwiazda, Roberto H; Hemming, Sidney R; Broecker, Wallace S (1996): Tracking the sources of icebergs with lead isotopes: The provenance of ice-rafted debris in Heinrich layer 2. Paleoceanography, 11(1), 77-93 ...