Abstract :
[en] Sm-Nd studies were carried out on Last Glacial and Holocene sediments from the Labrador Sea. Three grain-size fractions were analyzed for each sediment: the clay-size fraction (<2 mu m), the fine cohesive silts (2-10 mu m) and the coarse silts (10-63 mu m) In most cases, Sm-Nd signatures are different from one grain-size to another. In addition, different Sm-Nd signatures are derived from the clay-size fractions compared to the cohesive silt fraction, indicating that the cohesive fraction is heterogeneous and that distinct origins in terms of source-areas are implied. Silt fractions record the influence of supplies from the North American Precambrian Shield, whereas clay-size fractions (<2 mu m) are more sensitive to sedimentary input from the Eastern Basins, in relation with deep currents. Coupling Sm-Nd studies on silt and clay fractions may be a powerful tool to unravel the evolution of deep circulations versus detrital supplies. (C) 2000 Elsevier Science B.V. All rights reserved.
Disciplines :
Earth sciences & physical geography
Physical, chemical, mathematical & earth Sciences: Multidisciplinary, general & others
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