Pleistocene Glaciation: A Criterion for Recognition of Its Onset

The various biostratigraphic boundaries proposed for the base of the Pleistocene are not necessarily synchronous with the onset of continental glaciation. Electron-microscopic examination of surface textures of sand grains suggests a widely applicable rock-stratigraphic and geologic-climate boundary that may mark the point at which glaciers of continental proportions began to launch debris-carrying icebergs into the world's oceans.