Increased sedimentation rates and grain sizes 2±4 Myr ago due to the in ̄uence of climate change on erosion rates

Around the globe, and in a variety of settings including active and inactive mountain belts, increases in sedimentation rates as well as in grain sizes of sediments were recorded at ,2±4 Myr ago, implying increased erosion rates. A change in climate represents the only process that is globally synchronous and can potentially account for the widespread increase in erosion and sedimentation, but no single processÐlike a lowering of sea levels or expanded glaciationÐcan explain increases in sedimentation in all environments, encompassing continental margins and interiors, and tropical as well as higher latitudes. We suggest that climate affected erosion mainly by the transition from a period of climate stability, in which landscapes had attained equilibrium con®gurations, to a time of frequent and abrupt changes in temperature, precipitation and vegetation, which prevented ̄uvial and glacial systems from establishing equilibrium states.