Sm-Nd isotope systematics in deep-sea sediments: clay-size versus coarser fractions

• Published in: Marine Geology
• Main Authors: Innocent, C., Fagel, Nathalie, Hillaire-Marcel, C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier Science 2000
• Subjects: clay minerals; deep-sea sediments; Last Glacial maximum; Northwest Atlantic; Nd-144/Nd-143; Physical; chemical; mathematical & earth Sciences; Earth sciences & physical geography; Physique; chimie; mathématiques & sciences de la terre; Sciences de la terre & géographie physique; Labrador Sea
• Online Access: https://orbi.uliege.be/handle/2268/24758; https://orbi.uliege.be/bitstream/2268/24758/1/CI%20Sm%20Nd%20labrador%20margo%202000%20ocr.pdf; https://doi.org/10.1016/S0025-3227(00)00052-9

peer reviewed 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.