Late Pleistocene Glacial-Paleosol-cosmic record of the Viso Massif—France and Italy: New evidence in support of the Younger Dryas boundary (12.8 ka)

Mount Viso (3841 m asl), one of the highest mountains in the Western European Alps carries not only a glacial record following the end of the last glacial (Late Glacial-LG), but also a cosmic airburst record at approximately ~ 12.8 ka, presumably the black mat, that adds to a worldwide record of biomass burning which is considered to have triggered the Younger Dryas (YD) cooling episode. We combine the stratigraphic evidence of staggered Late Glacial retreat on both sides of the continental divide—faster in the upper Guil, possibly slower in the upper Po valleys—followed by superposed YD moraine overlapping LG in France, and stillstand of LG with overlapping YD in Italia with recovered cosmic evidence. Previously, we studied selected areas on the Viso massif, but here we expand on newly combined stratigraphic-cosmic airburst evidence, the latter lying in an uneven distribution of welded, melted and air-quenched clasts of pebble to sand-silt size in paleosols, all of which carry variable high to low REEs, high base metals, partial Pt and Ir coated surfaces indicative of nuclear-cosmic events. One of the outstanding conclusions of this research is the indisputable close correspondence of widespread cosmic airburst evidence with the YDB (Younger Dryas boundary) and onset of the YD. Thus, a test of catastrophism, firmly embedded in surficial sediment, yields some important underpinnings of Earth’s climatic history.