Late Eocene to present isotopic (Sr–Nd–Pb) and geochemical evolution of sediments from the Lomonosov Ridge, Arctic Ocean: Implications for continental sources and linkage with the North Atlantic Ocean - 09/11/15
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Abstract |
New geochemical and isotopic (Sr, Nd, Pb) data are presented for a composite sedimentary record encompassing the past 50Ma of history of sedimentation on the Lomonosov Ridge in the Arctic Ocean. The sampled sediments encompass the transition of the Arctic basin from an enclosed anoxic basin to an open and ventilated oxidized ocean basin. The transition from anoxic basin to open ventilated ocean is accompanied by at least three geochemical and isotopic shifts and an increase in elements (e.g., K/Al) controlled by detrital minerals highlighting significant changes in sediment types and sources. The isotopic compositions of the sediments prior to ventilation are more variable but indicate a predominance of older crustal contributions consistent with sources from the Canadian Shield. Following ventilation, the isotopic compositions are more stable and indicate an increased contribution from younger material consistent with Eurasian and Pan-African crustal sources. The waxing and waning of these sources in conjunction with the passage of water through Fram Strait underlines the importance of the exchange of water mass between the Arctic and North Atlantic Oceans.
Le texte complet de cet article est disponible en PDF.Keywords : Arctic Ocean, Lomonosov Ridge, Radiogenic isotopes, Basin evolution, Sediment provenance, Anoxic environments
Plan
Vol 347 - N° 5-6
P. 227-235 - septembre 2015 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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