Citizen Science in Archaeology : Developing a Collaborative Web Service for Archaeological Finds in Finland

Peer reviewe

Minimal erosion of Arctic alpine topography during late Quaternary glaciation

The alpine topography observed in manymountainous regions is thought to have formed during repeated glaciations of the Quaternary period1,2. Before this time, landscapes had much less relief1–3. However, the spatial patterns and rates of Quaternary exhumation at high latitudes—where cold-based glaciers may protect rather than erode landscapes—are not fully quantified. Here we determine the exposure and burial histories of rock samples from eight summits of steep alpine peaks in northwestern Svalbard (79.5 ◦ N) using analyses of 10Be and 26Al concentrations4,5. We find that the summits have been preserved for at least the past one million years. The antiquity of Svalbard’s alpine landscape is supported by the preservation of sediments older than one million years along a fjord valley6, which suggests that both mountain summits and low-elevation landscapes experienced very lo

Der Cartansche Parameter auf den Flächen, die keine Regelflächen sind

Theory and climate modelling suggest that the sensitivity of Earth’s climate to changes in radiative forcing could depend on the background climate. However, palaeoclimate data have thus far been insufficient to provide a conclusive test of this prediction. Here we present atmospheric carbon dioxide (CO2) reconstructions based on multi-site boron-isotope records from the late Pliocene epoch (3.3 to 2.3 million years ago). We find that Earth’s climate sensitivity to CO2-based radiative forcing (Earth system sensitivity) was half as strong during the warm Pliocene as during the cold late Pleistocene epoch (0.8 to 0.01 million years ago). We attribute this difference to the radiative impacts of continental ice-volume changes (the ice–albedo feedback) during the late Pleistocene, because equilibrium climate sensitivity is identical for the two intervals when we account for such impacts using sea-level reconstructions. We conclude that, on a global scale, no unexpected climate feedbacks operated during the warm Pliocene, and that predictions of equilibrium climate sensitivity (excluding long-term ice-albedo feedbacks) for our Pliocene-like future (with CO2 levels up to maximum Pliocene levels of 450 parts per million) are well described by the currently accepted range of an increase of 1.5 K to 4.5 K per doubling of CO2