Unraveling the oceanographic history of the Arctic Ocean and the evolution of weathering inputs from the surrounding continents, which have responded sensitively to local and global environmental changes (e.g.Moran et al., 2006), is of major importance for understanding the mechanisms driving global climatic changes. While there is evidence for extended periods of time with a perennial sea ice cover of the Arctic Ocean since 44 Ma and continuous perennial sea ice since about 36 Ma (Darby, 2014) the onset of Northern Hemisphere Glaciation (NHG) and its intensification in the late Pliocene between 2.4 and 2.9 Ma (e.g., Shackleton et al., 1984, Raymo, 1994 and Zachos et al., 2001; Flesche Kleiven et al., 2002) was accompanied by the build-up of major ice sheets on the continents surrounding the Arctic Ocean (Polyak et al., 2001 and Moran et al., 2006). As a consequence of enhanced glacial conditions a transition of the weathering regimes on land towards increased mechanical denudation occurred (e.g. Riebe et al., 2004).

Previous studies have invoked regional tectonic forcing (Matthiessen et al., 2009; Knies et al., 2014) and changes in ocean circulation in the North Atlantic linked to the closure of the Isthmus of Panama (Driscoll and Haug, 1998) as well as moisture export from the subarctic Pacific (Haug et al., 2005) as possible triggers for the onset of Plio-Pleistocene circum-Arctic glaciation. However, the exact temporal and spatial evolution of this pronounced climatic change is not well constrained from the marine sedimentary record in the Arctic Ocean as a consequence of the paucity of long sedimentary records. The only available record covering the past 55 million years was recovered during IODP Leg 302, the Arctic Coring Expedition (ACEX), from an intermediate water depth of 1200 m on the Lomonosov Ridge and is interrupted by a short and a long hiatus between 9.4 and 11.6 Ma and 18.2 and 44.4 Ma, respectively (Moran et al., 2006,Backman et al., 2006 and Backman et al., 2008). Several studies have analyzed climatically driven changes in the provenance of the sediments supplied to the core location. Haley et al. (2008b) for example applied radiogenic isotopes to demonstrate that detrital inputs in the central Arctic Ocean have been linked to climatic forcing of weathering on the Eurasian continental margin, whereas März et al. (2010) defined geochemical units (based on major and trace elements) representing changes in detrital provenance, as well as in paleoenvironmental and diagenetic processes. Other than that only Pliocene Arctic sediments have been accessible from some very low sedimentation rate locations such as in the vicinity of the Alpha Ridge (e.g. Winter et al., 1997), for which the age models are, however, not well constrained due to the absence of carbonate microfossils. Recent evidence suggested that the true maximum ages of these records are much younger than initially published (e.g. Jakobsson et al., 2000) but there is still debate on the age models of sediments in the western Arctic Ocean (e.g. Sellén et al., 2009).

Here we present the first combined seawater-derived radiogenic isotope records of Nd, Hf, and Pb obtained from three hydrogenetic Fe–Mn crusts from the Northwind Ridge in the Canada Basin, which are condensed chemical sediments and reflect the continuous evolution of weathering regimes and erosional inputs for the period from the late Miocene (7 Ma) to the present.