Acquisition of the neodymium isotopic composition of the North Atlantic Deep Water

摘要: The North Atlantic Deep Water (NADW) neodymium isotopic composition (Nd IC) is increasingly used in oceanography and paleoceanography to trace large-scale circulation weathering processes, notably investigate past variations of the global thermohaline circulation. Although present-day NADW Nd IC well characterized at e = A13.5, acquisition this signature (in other words, causes value) has so far been very sparsely documented. Such an understanding is, however, fundamental interpretation paleo records. rare earth element concentrations were measured 9 stations within Subpolar Gyre (SIGNATURE cruise, summer 1999). comparison data set with our water mass provides a description how three layers constituting NADW, Labrador Sea (LSW, A13.9 ± 0.4), East (NEADW, A13.2 West Bottom (NWABW, A14.5 acquire their through distinct mixings lithogenic inputs. These different mechanisms, acting upon masses from diverse sources, seem bring values close together similar that NADW. It suggested sediment/seawater interactions significantly lower NEADW NWABW along South Greenland margin. Since these do not modify content masses, sediment remobilizations leading are probably associated removal fluxes toward sediment, process called boundary exchange. On hand, LSW seems its Mode Waters which it formed by deep convection, no mechanism needs be invoked. Its unradiogenic could ultimately linked fresh runoff Canadian Shield. conclusions should allow more precise interpretations paleoceanographic records, taking into account histories layers, including Components: 12,506 6 figures, 4 tables.